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In the context of intensive and sustainable agriculture, limiting soil degradation and the loss of organic matter has become an obligation to maintain food security. The use of organo-mineral fertilizer (OMF) products is an innovative technology that may solve the different challenges raised. This study aimed to evaluate the effect of various organo-mineral fertilizer (OMF) formulations on Zea mays agro-physiological traits, phosphorus (P)-related parameters, and water conservation during a 90-day pot experiment. The OMF formulations consisted of blending several doses of a stable OMWS compost (10 t /ha(OMF1), 50 t/ha (OMF2), or 100 t/ha (OMF3)) with different sources of mineral P, namely diammonium phosphate (DAP), rock phosphate (RP), or phosphate washing sludge (PWS), compared with separate applications. The results indicated that the effect of an OMF on the soil and plants was strongly dependent on the source of P used and the dose of OMWS compost. The best agronomic performance was attributed to OMF1-based DAP, which resulted in a significant improvement in the shoot and root biomass dry weight by more than 260% and 40%, respectively. However, using an OMF2 formulation was more optimal when using RP and PWS as mineral P sources. Independently of the type of P fertilizer, the addition of stable OM systematically improved multiple soil properties, including water availability, and the nutrient concentrations, such as the available P, exchangeable potassium, and magnesium. Furthermore, the plant’s respiration, photosynthetic activity, and nutrient assimilations were positively affected by the OMF formulations. Overall, our results demonstrate that organo-mineral fertilization is a promising solution for increasing the efficiency of low-P and high-P mineral fertilizers in alkaline soils through direct and indirect mechanisms involving improved soil properties and higher P solubilization.

Soil pH plays an important role in soil nutrient dynamics and plant uptake, but its role in affecting nitrogen (REN) and phosphorus fertilizer use efficiency (REP) remains unclear. I used two meta-analyses to investigate the overall importance of soil pH and other factors for REN and REP, respectively in rice, wheat and maize. I found an average REN of 39%, and an average REP of 12%, based on 261 and 82 global studies, respectively. There was large variation among crops, as a result of different genotypes, growing conditions, soil characteristics, and fertilization rate. For REN, relationships with pH depended on crop type, where REN increased with soil pH for wheat, but decreased with soil pH for rice, while an optimum REN was observed for maize at neutral soil pH. In contrast, the lowest REP was observed for all crops near neutral soil pH. A one-month soil incubation experiment was conducted to examine effects of lime (CaCO3) and calcium hydroxide (Ca(OH)2) on soil pH and soil N and P dynamics. Both Ca(OH)2 and CaCO3 increased soil pH, while adding Ca(OH)2 to basic soil pH reduced nitrification and enhanced available P compared with adding CaCO3. I then conducted a glasshouse experiment with N and P fertilizer and lime treatments to investigate the interactive effects of lime, N and P addition on REN and REP in wheat. REN decreased with increased liming rate, possibly because liming enhanced net N mineralization in the soil thereby reducing crop dependency on the N fertilizer. In contrast, REP increased with increasing liming rate, possibly because of reduced P fertilizer fixation in the soil. Overall, REN and REP could be improved by adjusting N and P fertilization to environmental and soil conditions and by synchronizing with crop N and P demand and thereby reducing N and P loss.

A pot experiment was conducted to investigate the effects of P and Fe application on the biomass production and nutrients partitioning of two soybeans (Glycine max. L. Merr) cultivars grown in carbonated chernoziom (low in Fe and P) under water stress conditions. P and Fe were applied at two levels (0 and 100 mg P kg-1soil; 0 and 5 mg Fe kg-1soil). Control plants were grown at 70% water holding capacity (WHC) while their counterparts were subjected to 35% WHC water stress at initial flowering stage for two weeks. Considerable variability was observed in leaves, roots dry mass accumulation and nodulation among the soybean cultivars (Zodiac, Licurici) at both P and Fe levels in relation to water regimes. The results showed that drought significantly reduced biomass production irrespective of nutrient supply and its adverse effect was more pronounced at low nutrient supply. Leaf development and nodules growth were the most sensitive to water deficit and insufficient nutrient supply. Adequate P and Fe supply increased dry matter production and nutrient concentrations for soybean cultivars. Phosphorus concentration in plant parts was significantly higher at nil Fe compared with Fe application. Phosphorus application decreased Fe allocation to the leaves. The experimental results demonstrated that there was a positive effect of P and Fe adequate nutrition on P use efficiency. Hence, the sufficient phosphorus and iron supply maintained growth at high level, improved P and Fe status and partially alleviated drought effect on soybean plants.

The improvement of phosphorus (P) use efficiency (PUE) is a critical problem in crop production because of phosphorus’ scarcity. Especially in strongly weathered soil with a high P fixation capacity, a low PUE generally limits plant growth. Here, in a 70-day pigeon pea cultivation pot experiment using Ultisols, we evaluated the effects of Rhizobium inoculation (−I/+I) on the plant growth, rhizosphere, bulk soil P dynamics, and plant root P acquisition characteristics, with or without P fertilization (0P: no P application; 50SSP:50 kg P ha−1 with single superphosphate). The combination of Rhizobium inoculation with P fertilization (50SSP + I) increased the plant growth, P uptake, and organic acid content per pot by 63%, 41%, and 130%, respectively, but not without P fertilization (0P + I). The labile and moderately labile inorganic P (NaHCO3-Pi and NaOH-Pi) contents were higher (55% and 44%, respectively) in the rhizosphere soil than those in the bulk soil in the 50SSP + I treatment, indicating the efficient solubilization of the applied P under the 50SSP + I treatment. The fertilized PUE was higher in the 50SSP + I treatment (26%) than that in the 50SSP−I treatment (15%). Thus, these results suggest that Rhizobium inoculation with 50SSP should stimulate plant root P acquisition characteristics, leading to the solubilization of applied P in the rhizosphere and efficient plant P uptake. In conclusion, the 50SSP + I treatment effectively improved the PUE of pigeon peas in strongly weathered soil.

Phosphorous (P) fixation in saline soils is a concern worldwide. To investigate optimization strategies for P fertilizer application that improve P use efficiency (PUE) and crop yield in saline soil, in terms of P sources and rates, we conducted a two year field experiment in the coastal saline area of China to investigate the effects of P rates and sources, including superphosphate (SSP), monoammonium phosphate (MAP) and ammonium polyphosphate (APP) on yield, aboveground P uptake, agronomy efficiency (AEP), and soil available P of winter wheat (Triticum aestivum L.). Wheat yield, under the three P sources, increased with P rates and reached a plateau under 20 kg P ha−1 SSP,18 kg P ha−1 MAP, and 17 kg P ha−1 MAP, respectively. The application of SSP increased the wheat yield by 9–11% compared to MAP and APP. The aboveground P uptake of winter wheat under SSP was 14% and 13% higher than MAP and APP, respectively, under the optimal P application rate. The AEP under SSP was higher than the other two P sources under the same P rate. SSP increased the soil Ca2+ concentration by 20–42%, but decreased the Na+ concentration by 14–18% at the P rate of 26 kg P ha−1 in all soil layers, including 0–20, 20–40, 40–60 cm, compared to CK (0 kg P ha−1). The soil Olsen-P concentration under APP was higher than the other P sources. This study suggests that optimizing P sources and rates can improve wheat yield, PUE, and soil quality in the coastal saline soil.

Scarce findings on phosphorus (P) uptake and its utilization under increased zinc (Zn) levels in organic fertilizers amended soil led to conducting research. The aim of the study was to determine the effect of increasing the application of zinc (200, 400, and 600 mg·kg−1 of soil) together with different organic fertilizers (bovine manure, chicken manure, and spent mushroom substrate) on the content and uptake of phosphorus by cocksfoot and the phosphorus use efficiency from organic fertilizers. The application of different amounts of zinc did not affect phosphorus content in the grass, but it significantly influenced its accumulation (p < 0.05). The most phosphorus uptake was accumulated by plants following zinc application at 200 mg·kg−1 of soil and the least following application of 600 mg·kg−1 of soil. The phosphorus use efficiency from organic fertilizers was increased by zinc application of 400 mg·kg−1 of soil and reduced by 600 mg·kg−1 of soil. Organic fertilizers did not significantly affect the phosphorus content in the grass but did increase its uptake. The highest phosphorus use efficiency was obtained for bovine manure. The study showed no antagonistic relationships between zinc and phosphorus, but increasing zinc application affected the coefficient of phosphorus utilization from organic fertilizers.

The extent of intra‐annual turnover in phytoplankton communities is directly associated with the overall diversity. However, our understanding of the underlying causes and effects of intra‐annual turnover remains limited. In this study, we performed a two‐season investigation of the phytoplankton composition in the lakes of the Yangtze River catchment in China in spring and summer 2012, which covered a regional spatial scale. We analyzed the Sørensen pairwise dissimilarity (βsor) between the two seasons, their driving factors, and effects on resource use efficiency in phytoplankton. The results showed that the changes in phytoplankton composition from spring to summer were not synchronous among these lakes. The spatial environmental characteristics, temporal changes in environmental variables and the initial phytoplankton composition together explained the variation in βsor for phytoplankton, and their explanatory powers and primary driving variables depended on the phytoplankton taxonomic groups. Among the driving variables, increased nitrogen level and seasonal temperature difference will promote spring–summer community turnover and then improve the phosphorus use efficiency of phytoplankton community. The species diversity of the initial community might increase its stability and slow the spring–summer shift in phytoplankton, especially in cyanobacteria and Chlorophyta. Our study highlights the understanding of the patterns and underlying causes of temporal beta diversity in freshwater phytoplankton communities., We quantified the contributions of the spatial environmental characteristics, temporal changes in environmental variables, and the initial phytoplankton composition, and deciphered their paths affecting temporal beta diversity. We assessed the difference in response to the three types of variables among taxonomic groups of phytoplankton. We found that increased nitrogen level and seasonal temperature difference will promote spring–summer community turnover and then improve the phosphorus use efficiency of phytoplankton community.

Increasing phosphorus (P) use efficiency in agricultural systems is urgent and essential to significantly reduce the global demand for this nutrient. Applying phosphate-solubilizing and plant growth-promoting bacteria in the rhizosphere represents a strategy worthy of attention. In this context, the present work aimed to select and validate bacterial strains capable of solubilizing phosphorous and promoting maize growth, aiming to develop a microbial inoculant to be used in Brazilian agriculture. Bacterial strains from the maize rhizosphere were evaluated based on their ability to solubilize phosphate and produce indole acetic acid. Based on these characteristics, 24 strains were selected to be further evaluated under laboratory, greenhouse, and field conditions. Among the selected strains, four (I04, I12, I13, and I17) showed a high potential to increase maize root growth and shoot P content. Strains I13 (Ag87) and I17 (Ag94) were identified by genomic sequencing as Bacillus megaterium and Lysinibacillus sp., respectively. These strains presented superior yield increments relative to the control treatment with 30% P. In addition, combining Ag87 and Ag94 resulted in even higher yield gains, indicating a synergistic effect that could be harnessed in a commercial inoculant for Brazilian agriculture.

Phosphorus (P) is a vital macronutrient required for soybean growth and development but is a finite resource in agriculture worldwide. Low inorganic P availability in soil is often a significant constraint for soybean production. However, little is known about the response of P supply on agronomic, root morphology, and physiological mechanisms of contrasting soybean genotypes at various growth stages and the possible effects of different P on soybean yield and yield components. Therefore, we conducted two concurrent experiments using the soil-filled pots with six genotypes (deep-root system: PI 647960, PI 398595, PI 561271, PI 654356; and shallow-root system: PI 595362, PI 597387) and two P levels [0 (P0) and 60 (P60) mg P kg−1 dry soil] and deep PVC columns with two genotypes (PI 561271 and PI 595362) and three P levels [0 (P0), 60 (P60), and 120 (P120) mg P kg−1 dry soil] in a temperature-controlled glasshouse. The genotype × P level interaction showed that increased higher P supply increased leaf area, shoot and root dry weights, total root length, shoot, root, and seed P concentrations and contents, P use efficiency (PUE), root exudation, and seed yield at different growth stages in both experiments. At the vegetative stage (Experiment 1), shallow-rooted genotypes with shorter life cycles had more root dry weight (39%) and total root length (38%) than deep-rooted genotypes with longer life cycles under different P levels. Genotype PI 654356 produced significantly higher (22% more) total carboxylates than PI 647960 and PI 597387 under P60 but not at P0. Total carboxylates positively correlated with root dry weight, total root length, shoot and root P contents, and physiological PUE. The deep-rooted genotypes (PI 398595, PI 647960, PI 654356, and PI 561271) had the highest PUE and root P contents. In Experiment 2, at the flowering stage, genotype PI 561271 had the greatest leaf area (202%), shoot dry weight (113%), root dry weight (143%), and root length (83%) relative to the short-duration, shallow-rooted genotype PI 595362 with external P applied (P60 and P120), with similar trends at maturity. PI 595362 had a greater proportion of carboxylates as malonate (248%), malate (58%), and total carboxylates (82%) than PI 561271 under P60 and P120 but no differences at P0. At maturity, the deep-rooted genotype PI 561271 had greater shoot, root, and seed P contents and PUE than the shallow-rooted genotype PI 595362 under increased P rates but no differences at P0. Further, the genotype PI 561271 had higher shoot (53%), root (165%), and seed yield (47%) than PI 595362 with P60 and P120 than P0. Therefore, inorganic P application enhances plant resistance to the soil P pool and maintains high soybean biomass production and seed yield.

Introduction: Phosphorus is the third most important nutrient in crop production after nitrogen and potassium. It is involved in all biochemical processes, energetic compounds, and energy transfer mechanisms. Phosphorus participates in the cellular proteins and cell membrane and nucleic acids. In addition, this element is essential for seed formation and root development. Also, this element recovery in the first year of application estimates to be 8 to 30%, and after 30 years rarely reaches to 50% and its rest is stabilized in the soil and accumulates inaccessibly for most plants. Therefore, in the last two decades, scientists have used various methods to improve the efficiency of phosphorus, including the selection and genetic modification of plants and the adopting agricultural practices such as determining the optimal amount of phosphorus, the right time and method of application and the right fertilizer source. In addition, due to the growing trend of vegetable oil consumption and the high cost of supplying the required oil through imports, the purpose of this study was to determine the optimal rate of phosphorus and selecting the appropriate efficient cultivar in order to extend oilseed crops cultivation. Materials and Methods: In order to study the response of safflower cultivars (Carthamus tinctorius L.), to phosphorus rates and their efficiency indices, a factorial experiment was conducted in a randomized complete block design with three replications during 2012-13 and 2014-15 at Safiabad Agricultural Research Center of Dezful, Khuzestan, Iran. The first factor included five phosphorus levels (0, 50,100, 150 and 200 kg ha-1 as Triple Super Phosphate "TSP"), and the second factor included two cultivars (Goldasht and Soffeh). Safflower seeds were planted by setting up a sugar beet planter, in a row with a distance of 50 cm between rows and a distance of 5 cm between plants. Urea and potassium sulfate were uses at 300 and 100 kg ha-1, respectively. One-third of nitrogen and all phosphorus and potassium were used pre planting. The rest of urea fertilizer was applied as top dressing in two equal splitting rates (beginning of stem and early flowering stages). Before harvesting in each replication, the number of fertile heads per square meter (in three boxes of one square meter per plot), and the number of full grains (counting full grains in 20 heads), and after harvesting the weight of 1000 seeds (with three times counts were calculated in three random groups of 1000 seeds per plot). Finally, number of fertile heads per square meter, number of seeds per heads, 1000-seed weight, seed and oil yields, seed phosphorus uptake, and phosphorus efficiency indices were measured. Results and Discussion: The results showed that the interaction of treatments was significant on the number of fertile heads per square meter and number of seeds per head. In both cultivars, with increasing phosphorus application, the mentioned traits increased significantly. The highest number of fertile heads (252 pieces), and the number of seeds per head (23.17 pieces), were obtained at the level of 150 kg phosphorus ha-1. The interaction between year and phosphorus on 1000-seed weight and seed yield and the interaction between year and cultivar on 1000-seed weight were significant. The highest 1000-seed weight (42.41 g), and seed yield (2184 kg ha-1), were obtained by application of 100 kg phosphorus ha-1. Seed and oil yields of Soffeh cultivar (1979 and 599 kg ha-1, respectively), was superior to Goldasht cultivar. Also, the results showed that Goldasht cultivar had higher utilization efficiency (248 kg kg-1), compared to Soffeh cultivar (218 kg kg-1). Phosphorus application significantly reduced use and uptake efficiency indices (69% and 85%, respectively). So that the treatment without phosphorus application had the highest use and uptake efficiency (1 kg kg-1). The difference between use and uptake efficiency at the level of 50 kg phosphorus ha-1 with other phosphorus levels was about 19% and 25%, respectively. Conclusions: In general, due to the highest benefit-to-cost ratio (35.51) and use and uptake efficiency indices (0.69 and 0.7 kg .kg-1, respectively), application of 50 kg ha-1 of phosphorus fertilizer and Soffeh cultivar is recommended.

Maintaining carbohydrate biosynthesis and C assimilation is critical under phosphorus (P) deficiency as inorganic P (Pi) is essential for ATP synthesis. Low available P in agricultural soils occurs worldwide and fertilizer P sources are being depleted. Thus, identifying biosynthetic traits that are favorable for P use efficiency (PUE) in crops is crucial. This study characterized agronomic traits, gas exchange, and chlorophyll traits of two wheat genotypes that differ in PUE. RAC875 was a P efficient genotype and Wyalkatchem was a P inefficient genotype. The plants were grown in pots under growth room conditions at two P levels; 10 mg P kg–1 soil (low P) and 30 mg P kg–1 soil (adequate P) and gas exchange and chlorophyll fluorescence were measured at the vegetative and booting stages using a portable photosynthesis system (LI-6800, LI-COR, United States). Results showed significant differences in some agronomic traits between the two wheat genotypes, i.e., greater leaf size and area, and a higher ratio of productive tillers to total tillers in RC875 when compared with Wyalkatchem. The CO2 response curve showed Wyalkatchem was more severely affected by low P than RAC875 at the booting stage. The relative ratio of the photosynthetic rate at low P to adequate P was also higher in RAC875 at the booting stage. Photochemical quenching (qP) in RAC875 was significantly higher when compared with Wyalkatchem at the booting stage. Maintaining CO2 fixation capacity under low P and higher qP would be associated with P efficiency in RAC875 and measuring qP could be a potential method to screen for P efficient wheat.

Phosphorus use efficiency (PUE) can be improved through cultivation techniques and breeding. However, little is known about rice (Oryza sativa L.) agronomic and physiological traits associated with high PUE. We characterized the agronomic and physiological traits of rice varieties with different tolerances to low phosphorus in nutrient solution. Two varieties with strong tolerance to low phosphorus (STVs) and two with weak tolerance (WTVs) were grown at normal (NP, control) and low phosphorus (LP, 1/20 of NP) concentrations. Plants grown at LP produced significantly lower grain yield than those grown at NP. WTVs yields were lower than STVs yields. Compared to NP, LP significantly increased phosphorus translocation efficiency (PTE), internal phosphorus efficiency (IPE) and phosphorus harvest index (PHI). Under the LP condition, PTE and IPE were higher for STVs than for WTVs. LP also reduced tiller number, shoot biomass, leaf area index (LAI), leaf photosynthetic rate, and mean root diameter of both kinds of varieties at the main growth stages, but to a lower extent in STVs. LP significantly increased the number of productive tillers, root biomass, root-shoot ratio, root bleeding rate, and root acid phosphatase (RAP) activity. Total root length, root oxidation activity (ROA), and root total and active absorbing surface areas for STVs were significantly increased under LP, whereas the opposite responses were observed for WTVs. Total root length, ROA, root bleeding rate, root active absorbing surface area, and RAP activity were positively and significantly correlated with grain yield, PTE, and IPE. These results suggest that the tolerance of rice varieties to a low-phosphorus growth condition is closely associated with root growth with higher biomass and activity.

Development of local P fertilizers using low-grade phosphate rock (PR) is expected to overcome the low-stagnated crop yield in Sub-Saharan Africa. Calcination and partial acidulation methods have been proposed to increase the phosphate (P) solubility of PRs. However, the effects of fertilization with calcinated PR (CPR) and partially acidulated PR (PAPR) on sorghum [Sorghum bicolor (L.)] and cowpea [Vigna unguiculata (L.) Walp.] cultivation are poorly understood. Therefore, we conducted a 2-year field experiment in Burkina Faso to identify the differences in sorghum and cowpea responses to CPR and PAPR application. The following eight treatments were applied with six replicates using a complete randomized block design: control without P fertilization, two types of CP (CPs), triple superphosphate (TSP) as a positive control for CPs, three types of PAPR with different degrees of acidulation (PAPRs), and single superphosphate (SSP) as a positive control for PAPRs. SSP mostly comprised of water-soluble P fraction (WP), TSP and PAPRs of WP and alkaline ammonium citrate-soluble P fraction (SP), and CPRs of SP and 2% citric acid-soluble P fraction (CP). Their solubility was in the order WP > SP > CP. The fertilization effects were evaluated by P use efficiency (PUE). In 2019, the biomass and P uptake of sorghum was decreased by the low available soil water at the early growth stage. On the contrary, cowpea survived the low available soil water because of its shorter growing period compared to sorghum. P fertilization significantly increased the grain yields. However, the effect size differed according to the crop and fertilizer types. The SP, along with WP, significantly contributed to the PUE and grain yield of sorghum, whereas only WP contributed to the PUE of cowpea. Therefore, CPs, mainly consisting of SP and CP, had a disadvantage compared to TSP, especially for cowpea. We thus concluded that PAPRs are effective for sorghum and would be effective for cowpea when the acidulation level is sufficiently high. We also conclude that the long growing period of sorghum is favorable for absorbing slow-release P, but is unfavorable for the variable rainfall often observed in this region.

When soils are phosphorus (P) deficient, external sources in the form of fertilisers have to be applied to increase crop yields. The world depends on mined sources for P fertilisers, and recent reports indicate that an increase in the human population has led to rising demand for P fertilisers, making its future supply uncertain. A low supply of chemical P fertilisers may lead to food insecurity. Although the efficacy of organic sources of P is unclear, organic waste materials containing P can potentially replace inorganic P sources. Previously, organic fertilisers have been used to supply N and even P, but the application rates were mostly N based, resulting in inconsistent and comparable results. This research was conducted to understand P mineralisation and the availability of the P-based organic fertilisers. The results showed that available P in the soil at 3 weeks accounted for 50%, 6 weeks accounted for 49%, and 9 weeks counted for 46% of the maize yield. The organic P sources maintained soil available P above the threshold available P value in Malawi. The P sources did not affect the maize P use efficiency (PUE). The results indicate that organic P sources could be used as an alternative fertiliser for maize production in Malawi., Resources, 11 (10), ISSN:2079-9276

Phosphorus (P) is an essential, non-renewable resource critical for crop productivity across the world. P is immobile in nature and, therefore, the identification of novel genotypes with efficient P uptake and utilization under a low P environment is extremely important. This study was designed to characterize eighty genotypes of different Lens species for shoot and root traits at two contrasting levels of P. A significant reduction in primary root length (PRL), total surface area (TSA), total root tips (TRT), root forks (RF), total dry weight (TDW), root dry weight (RDW) and shoot dry weight (SDW) in response to P deficiency was recorded. A principal component analysis revealed that the TDW, SDW and RDW were significantly correlated to P uptake and utilization efficiency in lentils. Based on total dry weight (TDW) under low P, L4727, EC718309, EC714238, PL-97, EC718348, DPL15, PL06 and EC718332 were found promising. The characterization of different Lens species revealed species-specific variations for the studied traits. Cultivated lentils exhibited higher P uptake and utilization efficiency as compared to the wild forms. The study, based on four different techniques, identified EC714238 as the most P use-efficient genotype. The genotypes identified in this study can be utilized for developing mapping populations and deciphering the genetics for breeding lentil varieties suited for low P environments.

Controlled release phosphorus (P) fertilizers and humic acid (HA) applications are two effective and significant techniques or measures for preventing P loss and enhancing maize development. However, the underlying physiological mechanism of how the controlled release P fertilizers combined with HA affect the maize production and P-use efficiency (PUE) remains unknown. The effects of applying coated diammonium phosphate (CDAP) and HA together on soil nutrient supply intensity, soil phosphatase activity, photosynthesis, endogenous hormone contents, and yield of maize, as well as PUE, were examined in this study. In a pot experiment, two types of P fertilizers—CDAP and diammonium phosphate (DAP)– as well as two HA application rates (0 and 45 kg ha–1) and two P levels (60 and 75 kg P2O5 ha–1) were utilized. Results showed that the key elements that influence the growth and yield of the maize were the availability of P content in soil, plant photosynthesis, and hormone levels. The combination of CDAP and HA had a greater impact on yield and PUE over the course of 2 years than either DAP alone or DAP combined with HA. Besides, using CDAP in combination with HA increased the yield and PUE by 4.2 and 8.4%, respectively, as compared to the application of CDAP alone at 75 kg P2O5 ha–1. From the twelve-leaf to milk stages, the available P content in the soil was increased by an average of 38.6% with the combination of CDAP and HA compared to the application of CDAP alone at 75 kg P2O5 ha–1. In addition, the application of CDAP combined with HA boosted the activities of ATP synthase, as well as the content of cytokinin (CTK), and hence improved the maize photosynthetic rate (Pn). When compared to the application of CDAP alone or DAP combined with HA, the Pn of CDAP + HA treatments was enhanced by 17.9–35.1% at the same P rate. In conclusion, as an environmentally friendly fertilizer, the combined application of CDAP and HA improved the intensity of the soil nutrient supply, regulated photosynthetic capabilities, and increased the yield and PUE, which is important for agricultural production, P resource conservation, and environmental protection.

Novel biotechnology on transgenic plants capable of metabolizing phosphite (Phi), a reduced form of P, could improve the effectiveness of P fertilizers and reduce the P footprint in agriculture with the benefit of suppressing weed growth. However, potassium Phi (K-Phi) salts used as fertilizer are highly soluble in water. At the same time, sandy soils of the Southern Coastal Plain are vulnerable to leaching losses resulting from long-term Pi fertilizer application. We performed a replicated leaching trial using five soil materials that included three surface and two subsurface layers from cultivated topsoil (Ap horizon) with contrasting Phi and Pi sorption capacities. Each soil received three treatments K-Phi at rates 0 (control), 24, and 49 kg P ha−1 and leached twice with de-ionized water. All K-Phi-treated soils leached Phi except for the controls. A phosphorus saturation ratio (PSR) calculated from P, Al, and Fe in acid extracts indicated increasing environmental risk of Phi leaching in soils with lower Phi and Pi sorption capacities at rising rates of applied K-Phi. Because plants rapidly absorb Phi, further studies on the environmental impact of K-Phi fertilizer use should include the interaction of plants with soil properties and soil microbial activity at optimal Phi application rates for growing transgenic plants able to use Phi as a nutrient source.

Crops with superior phosphorus (P) use efficiency (PUE) provide a financial advantage to growers and a reduced environmental burden. Progress is needed to breed winter wheat (Triticum aestivum L.) for PUE. The objectives of this thesis were to: 1) examine the P response of winter wheat genotypes across traits and environments; 2) improve methods for assessing PUE; 3) identify quantitative trait loci (QTL) for traits related to PUE; 4) assess winter wheat for root system architecture (RSA) traits important for PUE. Two-hundred winter wheat genotypes were assessed under differential P conditions over three environments. A subset with varied P response was phenotyped under controlled conditions for RSA traits, for which genetic variation was found. Genetic variation was found for P response, which was inconsistent across environments. Additionally, P treatment-specific QTL were found. Through this thesis, a PUE phenotyping method suitable for regions with historically high P inputs was developed. Natural Sciences and Engineering Research Council of Canada; Ontario Ministry of Agriculture, Food and Rural Affairs; University of Guelph

Phosphorus (P) deficiency is an important challenge the world faces while having to increase crop yields. It is therefore necessary to select maize (Zea may L.) genotypes with high phosphorus use efficiency (PUE). Here, we extensively analyzed the biomass, grain yield, and PUE-related traits of 359 maize inbred lines grown under both low-P and normal-P conditions. A significant decrease in grain yield per plant and biomass, an increase in PUE under low-P condition, as well as significant correlations between the two treatments were observed. In a genome-wide association study, 49, 53, and 48 candidate genes were identified for eleven traits under low-P, normal-P conditions, and in low-P tolerance index (phenotype under low-P divided by phenotype under normal-P condition) datasets, respectively. Several gene ontology pathways were enriched for the genes identified under low-P condition. In addition, seven key genes related to phosphate transporter or stress response were molecularly characterized. Further analyses uncovered the favorable haplotype for several core genes, which is less prevalent in modern lines but often enriched in a specific subpopulation. Collectively, our research provides progress in the genetic dissection and molecular characterization of PUE in maize.

Phosphorus is one of the second most important nutrients for plant growth and development, and its importance has been realised from its role in various chains of reactions leading to better crop dynamics accompanied by optimum yield. However, the injudicious use of phosphorus (P) and non-renewability across the globe severely limit the agricultural production of crops, such as rice. The development of P-efficient cultivar can be achieved by screening genotypes either by destructive or non-destructive approaches. Exploring image-based phenotyping (shoot and root) and tolerant indices in conjunction under low P conditions was the first report, the epicentre of this study. Eighteen genotypes were selected for hydroponic study from the soil-based screening of 68 genotypes to identify the traits through non-destructive (geometric traits by imaging) and destructive (morphology and physiology) techniques. Geometric traits such as minimum enclosing circle, convex hull, and calliper length show promising responses, in addition to morphological and physiological traits. In 28-day-old seedlings, leaves positioned from third to fifth played a crucial role in P mobilisation to different plant parts and maintained plant architecture under P deficient conditions. Besides, a reduction in leaf angle adjustment due to a decline in leaf biomass was observed. Concomitantly, these geometric traits facilitate the evaluation of low P-tolerant rice cultivars at an earlier stage, accompanying several stress indices. Out of which, Mean Productivity Index, Mean Relative Performance, and Relative Efficiency index utilising image-based traits displayed better responses in identifying tolerant genotypes under low P conditions. This study signifies the importance of image-based phenotyping techniques to identify potential donors and improve P use efficiency in modern rice breeding programs.

Made available in DSpace on 2019-10-06T16:12:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-02-07 Silicon (Si) can increase phosphorus (P) use efficiency (PUE) by increasing P availability in the soil and altering P metabolism in the plant, thus resulting in improved yield under low soil P conditions. The objective was to evaluate the effect of P (10, 50, 100, and 200 mg dm −3 ) and Si (0, 50, and 200 mg dm −3 ) interrelationship on P and Si uptake by plants, forms of P in leaves and tubers, plant growth, and tuber yield of potato plants. Silicon supply increased organic and inorganic P in the leaves. At low soil P rates, Si also increased organic P in the tubers. However, alterations in the P metabolism of potato plants with Si supply did not promote significant changes in dry matter (DM) production and tuber yield. Phosphate fertilization increased growth and yield of plants. Silicon uptake by the plants were also increased by phosphate fertilization with soil Si supply. Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP) Department of Crop and Soil Sciences University of Georgia Department of Crop Science College of Agricultural Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches São Paulo State University (UNESP)

Highlights • Five indicators for rice production and their gaps were assessed in 12 countries. • The indicators include yield, profit, labor productivity, N- and P-use efficiencies. • Mean yield varied: 2.5–5.6 t ha−1 in irrigated and 0.6–2.3 t ha−1 in rainfed. • There were yield gaps of 29–69 % and profit gaps of 10–89 %. • Less than 50 % of farmers had desirable ranges in N- or P-use efficiencies., The benchmarking and monitoring of rice production performance indicators are essential for improving rice production self-sufficiency, increasing profitability, reducing labor requirements, optimizing fertilizer inputs, engaging youths in rice production, and increasing the overall sustainability of smallholder rice production systems in countries in sub-Saharan Africa (SSA). In this paper, we quantified five sustainability performance indicators (grain yield, net profit, labor productivity, and nitrogen (N) and phosphorus (P) use efficiencies) to benchmark rice production systems in SSA. Data were collected between 2013–2014 from 2907 farmers from two rice production systems (irrigated and rainfed lowlands) across five agroecological zones (arid, semiarid, humid, subhumid and highlands) in 12 countries (Benin, Cameroon, Cote d’Ivoire, Ghana, Madagascar, Mali, Niger, Nigeria, Senegal, Sierra Leone, Tanzania and Togo). The exploitable gap for each indicator (the difference between the mean of 10 % highest-yielding farms and the mean-yielding farms) was calculated across the countries, the two production systems and agroecological zones. The mean yield varied widely between 2.5 to 5.6 t ha−1 and 0.6 to 2.3 t ha−1 in irrigated and rainfed lowlands, respectively, with an average yield of 4.1 and 1.4 t ha−1, respectively. Across the country-production system combinations, there were yield gaps of 29–69 %, profit gaps of 10–89 %, and labor productivity gaps reaching 71 %. Yield, profit, and labor productivity were positively correlated. They were also positively correlated with N and P fertilizer application rate, but not with N and P use efficiencies. Only between 34–44 % of farmers had desirable ranges in N- or P-use efficiencies in the two production systems. All sites for rainfed lowlands were characterized by low-yield and large gaps in yield, profit, and labor productivity, whereas irrigated lowlands in some countries (Madagascar, Mali, and Togo) have similar characteristics as rainfed ones. We conclude that there is an urgent need to disseminate precision nutrient management practices for optimizing nutrient use efficiency and enhancing rice performance indicators especially in rainfed lowlands as well as low-yielding irrigated lowlands. Furthermore, we propose recommendations for specific categories (i.e. farmer, rice production system, agroecological zone and country) to close performance indicator gaps and to allow the production at scale to achieve rice self-sufficiency in SSA.

Decomposed organic materials, in combination with plant growth-promoting bacteria (PGPB), are environmentally friendly and reduce synthetic fertilizer use in rice production. A bio-organic fertilizer (BoF) was prepared using kitchen waste (79%), chita-dhan (unfilled rice grain) biochar (15%), rock phosphate (5%), and a consortium of 10 PGPB (1%) to supplement 30% nitrogen and to replace triple superphosphate (TSP) fertilizer in rice production with an improvement of soil health. PGPB were local isolates and identified using 16S ribosomal RNA partial gene sequences as Bacillus mycoides, Proteus sp., Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Paenibacillus polymyxa, and Paenibacillus spp. Isolates could fix N2 by 0.7–1.4 g kg–1, solubilize 0.1–1.2 g kg–1 phosphate, and produce 0.1–40 g kg–1 indoleacetic acid. The performance of BoF was evaluated by 16 field experiments and 18 farmers’ field demonstration trials during the year 2017–2020 in different parts of Bangladesh. Performances of BoF were evaluated based on control (T1), full synthetic fertilizer dose of N, P, and K (T2), BoF (2 t ha–1) + 70% N as urea + 100% K as muriate of potash (T3), 70% N as urea + 100% P as TSP + 100% K as muriate of potash (T4), and 2 t ha–1 BoF (T5) treatments. At the research station, average grain yield improved by 10–13% in T3 compared with T2 treatment. Depending on seasons, higher agronomic N use efficiency (19–30%), physiological N use efficiency (8–18%), partial factor productivity (PFP)N (114–150%), recovery efficiency (RE)N (3–31%), N harvest index (HIN) (14–24%), agronomic P use efficiency (22–25%), partial factor productivity of P (9–12%), AREP (15–23%), and HIP (3–6%) were obtained in T3 compared with T2 treatment. Research results were reflected in farmers’ field, and significant (P < 0.05) higher plant height, tiller, panicle, grain yield, partial factor productivity of N and P were obtained in the same treatment. Application of BoF improved soil organic carbon by 6–13%, along with an increased number of PGPB as compared with full synthetic fertilizer dose. In conclusion, tested BoF can be considered as a green technology to reduce 30% synthetic N and 100% TSP requirements in rice production with improved soil health.

Bu çalışma, kireçli ve bazik reaksiyonlu bir toprakta 2 farklı formda (MAP-H2PO4- ve DAP-HPO4=) ve artan miktarlarda uygulanan fosfor, elementel (toz) kükürt ve K-Humat uygulamalarının ekmeklik buğday bitkisinin fosfor alım etkinliği üzerine etkilerini belirlemek için sera ve tarla koşullarında yürütülmüştür. Bu amaçla Bayraktar 2000 ekmeklik buğday çeşidine sera denemesinde bitkinin fosfor alım etkinliklerini belirlemek için saksılara fosfor (0, 30, 60 ve 90 mg P2O5 kg-1) ve K-Humat (0, 200 ve 400 mg HA kg-1) uygulanmıştır. Deneme tesadüf parselleri deneme desenine göre üç tekerrürlü olarak kurulmuş ve yürütülmüştür. Serada elde edilen bulgulara göre primer ortofosfat (H2PO4-) formunda fosfor uygulanmaları ile en yüksek PAE, PFE ve PGAO uygulamalara bağlı olarak değişmekle birlikte sırasıyla 1 kg toprağa 30 mg P2O5 (P30), K-Humat uygulanmadığında sadece 1 kg toprağa 30 mg P2O5 (P30*HA0) veya sadece 90 mg P2O5 (P90*HA0), 1 kg toprağa 30 mg P2O5 ile birlikte 400 mg K-Humat (P30*HA400) uygulamaları ile elde edilmiştir. Sekonder ortofosfat (HPO4--) formunda fosfor uygulanmaları ile en yüksek PAE ve PFE 1 kg toprağa 30 mg P2O5 ile birlikte 400 mg K-Humat (P30*HA400) uygulamaları ile belirlenirken PGAO 1 kg toprağa K-Humat uygulanmadığında 90 mg P2O5 (P90) uygulaması ile elde edilmiştir. Tarla denemeleri Bahri Dağdaş Uluslararası Tarımsal Araştırma Enstitüsü deneme alanında tesadüf bloklarında üç faktörlü faktöriyel deneme desenine göre 4 tekerrürlü olarak kurulmuş ve yürütülmüştür. Bayraktar 2000 ekmeklik buğday bitkisinin fosfor alım etkinliklerini belirlemek için fosfor (0, 4 ve 8 kg), kükürt (0 ve112.5 kg S da-1) ve K-Humat (0 ve 1.2 kg HA da-1) uygulanmıştır. Tarla koşullarında elde edilen bulgulara göre primer ortofosfat (H2PO4-) formunda fosfor uygulanmaları ile en yüksek PAE ve PFE uygulamalara bağlı olarak değişmekle birlikte en fazla dekara 4 kg P2O5, 112.5 kg S ve 1.2 kg K-Humat uygulamaları ile elde edilmiştir. PGAO ise dekara 4 kg P2O5 uygulaması ile belirlenmiştir. Sekonder ortofosfat (HPO4--) formunda fosfor uygulanmaları ile en yüksek PAE dekara 4 kg P2O, veya 1.2 kg K-Humat uygulamaları ile bulunurken, PPE 8 kg P2O5 veya 1.2 kg K-Humat uygulamaları ile bulunmuştur. En fazla PGAO ise dekara 4 kg P2O5 uygulaması ile belirlenmiştir., This study was carried out in a greenhouse and field conditions to determine the effects of increasing phosphorus, elemental (powder) sulfur, and K-Humat applications when phosphorus applied in 2 different forms (MAP-H2PO4- and DAP-HPO4=) on the phosphorus uptake efficiency of bread wheat in a calcareous and basic reaction soil. For this purpose, phosphorus (0, 30, 60, and 90 mg P2O5 kg-1) and K-Humat (0, 200, and 400 mg HA kg-1) were applied to Bayraktar 2000 bread wheat variety to determine the phosphorus uptake efficiency of the plant in the greenhouse experiment. The greenhouse experiments were established according to Completely Randomized Design within three replications. According to the results obtained in the greenhouse, the application of phosphorus in the form of primary orthophosphate (H2PO4-), the highest varies of the APUE, PPUE, and ARPUE determined on the application 30 mg P2O5 (P30) without K-Humat application to 1 kg of soil (P30*HA0), only 30 mg P2O5 (P30*HA0)or 90 mg P2O5 without K-Humat application to 1 kg of soil, and 30 mg P2O5 (P30) with 400 mg K-Humat application (P30*HA400) to 1 kg of soil respectively. Besides that, the highest APUE and PPUE are determined by the applications of 30 mg P2O5 with 400 mg K-Humate (P30*HA400) together to 1 kg of soil with the application of phosphorus in the form of secondary orthophosphate (HPO4--), while the highest ARPUE determined by 90 mg P2O5 (P90) without K-Humate application to 1 kg soil. Also, in the field experiments were established and carried out in the experimental area of Bahri Dağdaş International Agricultural Research Institute according to a three-factor factorial Randomized Complete Block Design in 4 replications. Phosphorus (0, 4, and 8 kg P2O5 da-1), sulfur (0 and 112.5 kg S da-1), and K-Humat (0 and 1.2 kg HA da-1) were applied on the soil to determine the effects of applications of them on the phosphorus uptake efficiency of Bayraktar 2000 bread wheat plant. According to the results obtained in dry field conditions, the phosphorus application in the form of primary orthophosphate (H2PO4-) with kükürt and K-Humat applications, the highest rate APUE and PPUE values obtained with 4 kg P2O5, 112.5 kg S, and 1.2 kg K-Humat applications per decare. Also, the ARPUE was determined by application of 4 kg P2O5 per decare. While with phosphor applications in the form of secondary orthophosphate (HPO4--), the highest APUE was found with 4 kg P2O5, or 1.2 kg K-Humat applications per decare, PPUE was found with 8 kg P2O5, or 1.2 kg K-Humat applications. Also, the highest ARPUE was determined by the application of 4 kg P2O5 per decare., Bu tez çalışması S.Ü. BAP Koordinatörlüğü tarafından 18201093 nolu proje ile desteklenmiştir

CONTEXT\ud Identifying the determinants of phosphorus (P) balance and use efficiency (PUE) is critical to improving the sustainability of dairy farming in countries operating diverse dairy farming systems because each system contributes to eutrophication through different pathways. However, information about P balance and PUE across diverse dairy farming systems is scarce.\ud \ud OBJECTIVE\ud The current study aimed to use a novel approach to determine P balance and PUE, and identify their key determinants across diverse dairy farming systems in GB.\ud \ud METHODS\ud Data from 29 dairy farms representing systems with differing feeding approaches and production levels was collected from farm records or generated by quantifying P concentration in feed, manure, and soil samples. The methodology of the nutrient management tool ‘Planning for Land Application of Nutrients for Efficiency and the environmenT (PLANET) and the principles of ‘Annual Nutrient Cycling Assessment’ (ANCA) were used to calculate farm-gate P balance (FPB) and soil-surface P balance (SPB), respectively. Differences in P balance and PUE between dairy farming systems were investigated using ANOVA. Determinants of P balance and PUE were identified using multiple stepwise linear regressions.\ud \ud RESULTS AND CONCLUSIONS\ud The current study demonstrated a novel approach of calculating FPB and SPB that captures differences in the P concentration of manure and milk between systems.\ud \ud Phosphorus surplus was higher and PUE was lower in housed systems compared to pasture-based systems (except for a Spring-calving system grazing ≥274 days/year) primarily because of greater import of concentrate feed, highlighting the importance of reducing concentrate feed import into housed systems to minimise P import. Farms with greater inclusion rate of home-grown feed (primarily forages) in their herds' diet had higher PUE and lower P surplus. Thus, pasture-based systems could improve PUE by increasing the inclusion rate of home-grown feeds in the herd diet only if they maintain a stocking rate that matches the feed demand of the herd to the availability of home-grown feeds. In conclusion, the assessment of PUE and strategies to improve it should consider system classification beyond strict housed and pasture-based systems.\ud \ud SIGNIFICANCE\ud The current study demonstrated the foundations of an approach to calculate FPB and SPB that could be more robust compared to using standard P coefficients particularly in countries that operate diverse dairy farming systems. With further development, this approach could be adopted and could change the way GB dairy farmers and advisers calculate P balances in diverse systems.

Due to the finite stocks of phosphate rock and low phosphorus (P) use efficiency (PUE) of traditional mineral P fertilizers, more sustainable alternatives are desirable. One possibility is to culture microalgae in wastewater to recover the P and then convert the microalgae biomass into slow-release fertilizers through hydrothermal carbonization (HTC). Therefore, this study aimed to recycle P from wastewater to agricultural field using microalgae and HTC technology. Chlorella vulgaris (CV) and Microcystis sp. (MS) were cultured in poultry farm wastewater with an initial concentration of 41.3 mg P kg−1. MS removed 88.4% P from the wastewater, which was superior to CV. CV- and MS-derived hydrochars were produced at 200 or 260 °C, in solutions using deionized water or 1 wt% citric acid. The MS-derived hydrochar using 1 wt% citric acid solution at 260 °C (MSHCA260) recovered the highest amount of P (91.5%) after HTC. The charring promoted the transformation of soluble and exchangeable P into moderately available P (Fe/Al-bound P), and using citric acid solution as feedwater increased the P recovery rate and formation of Fe/Al-bound P. With the abundant moderately available P pool, hydrochar amendment released P more slowly and enhanced the soil P availability more persistently than chemical fertilizer did, which helped to improve PUE. In a wheat-cultivation pot experiment, MSHCA260 treatment improved wheat PUE by 34.4% and yield by 21.6% more than chemical fertilizer did. These results provide a novel sustainable strategy for recycling P from wastewater to crop-soil systems, substituting the mineral P fertilizer, and improving plant PUE.

The nonrenewable nutrient phosphorus (P) has low mobility in soil and is often present in forms that are unavailable to crop plants. Alternate wetting and drying irrigation is one of the widely promoted water‐saving irrigation techniques and can increase mineral nutrient availability; however, its interaction with P in paddy fields remains unclear. We conducted a 4‐year field experiment to determine whether a specific regime of frequent alternate wetting and drying (FAWD15) irrigation and low P usage (P45) had synergistic effects on rice yield, rice growth, water use efficiency (WUE), agronomic P use efficiency (AEp), and soil residual fertilizer P. We found that compared to the continuously flooded (CF) irrigation, FAWD15 irrigation maintained rice yield under low P usage condition in a 4‐year field trial. Our results also showed that under low P usage, FAWD15 resulted in high AEp and WUE, and reduced residual fertilizer P. Further, FAWD15 irrigation increased labile P release and resulted in increased root growth by improving root sucrose distribution. These results suggest that FAWD15 irrigation can mitigate the effect of low P usage on rice grain yield by increasing soil P release and root growth in paddy fields.

Agriculture will face many challenges regarding food security and sustainability. Improving phosphorus use efficiency is of paramount importance to face the needs of a growing population while decreasing the toll on the environment. Pepper (Capsicum spp.) is widely cultivated around the world, hence, any breakthrough in this field would have a major impact in agricultural systems. Herein, the response to phosphorus low-input conditions is reported for 25 pepper accessions regarding phosphorus use efficiency, biomass and root traits. Results suggest a differential response from different plant organs to phosphorus starvation. Roots presented the lowest phosphorus levels, possibly due to mobilizations towards above-ground organs. Accessions showed a wide range of variability regarding efficiency parameters, offering the possibility of selecting materials for different inputs. Accessions bol_144 and fra_DLL showed an interesting phosphorus efficiency ratio under low-input conditions, whereas mex_scm and sp_piq showed high phosphorus uptake efficiency and mex_pas and sp_bola the highest values for phosphorus use efficiency. Phosphorus low-input conditions favored root instead of aerial growth, enabling increases of root total length, proportion of root length dedicated to fine roots and root specific length while decreasing roots&rsquo, average diameter. Positive correlation was found between fine roots and phosphorus efficiency parameters, reinforcing the importance of this adaptation to biomass yield under low-input conditions. This work provides relevant first insights into pepper&rsquo, s response to phosphorus low-input conditions.

The phosphorus nutrition status of European forests has decreased significantly in recent decades. For a deeper understanding of complementarity and competition in terms of P acquisition in temperate forests, we have analyzed &alpha, diversity, organic layer and mineral soil P, P nutrition status, and different concepts of P use efficiency (PUE) in Fagus sylvatica L. (European beech) and Picea abies (L.) H. Karst. (Norway spruce). Using a subset of the Second National Soil Survey in Germany, we correlated available data on P in the organic layer and soil with &alpha, diversity indices for beech and spruce forests overall and for individual vegetation layers (tree, shrub, herb, and moss layers). Moreover, we investigated &alpha, diversity feedbacks on P nutrition status and PUE of both tree species. The overall diversity of both forest ecosystems was largely positively related to P content in the organic layer and soil, but there were differences among the vegetation layers. Diversity in the tree layer of both forest ecosystems was negatively related to the organic layer and soil P. By contrast, shrub diversity showed no correlation to P, while herb layer diversity was negatively related to P in the organic layer but positively to P in soil. A higher tree layer diversity was slightly related to increased P recycling efficiency (PPlant/Porganic layer) in European beech and P uptake efficiency (PPlant/Psoil) in Norway spruce. The diversity in the herb layer was negatively related to P recycling and uptake efficiency in European beech and slightly related to P uptake efficiency in Norway spruce. In spruce forests, overall and herb species richness led to significantly improved tree nutrition status. Our results confirm significant, non-universal relationships between P and diversity in temperate forests with variations among forest ecosystems, vegetation layers, and P in the organic layer or soil. In particular, tree species diversity may enhance complementarity and hence also P nutrition of dominant forest trees through higher PUE, whereas moss and herb layers seemed to show competitive relationships among each other in nutrient cycling.

The traditional manure management strategy, based on crop N needs, results in accumulation of phosphorus (P) in soil due to the imbalance of N/P ratio between crop requirement and manure supply. This study was conducted from 2004 to 2013 to evaluate the effects of P-based liquid and solid swine manure (LMP and SMP, for P-based liquid and solid swine manure, respectively) application, in comparison with N-based application (LMN and SMN, for N-based liquid and solid swine manure, respectively), on crop yield and soil residual P under corn (Zea mays L.)–soybean (Glycine max L.) rotation in a Brookston clay loam soil of the Lake Erie basin, ON, Canada. Chemical fertilizer P (CFP) and non-P treatments were included as controls (CK). For liquid manure treatments, corn yield for LMN showed a lower annual corn yield (7.82 Mg ha−1) than LMP (9.36 Mg ha−1), and their differences were even statistically significant at p &lt, 0.05 in some cropping years. The annual corn yield of LMP was also higher than those of SMP (7.45 Mg ha−1) and SMN (7.41 Mg ha−1), even the CFP (8.61 Mg ha−1), although the corresponding yield differences were not significant (p &lt, 0.05) in some cropping years. For soybean, the plots with P application produced an average of 0.98 Mg ha−1 greater annual yields than CK. No significant differences were found between CFP and manure treatments. The annual corn yield of SMN was close to that of the CK (7.19 Mg ha−1). The grain P removal (GPR) of SMN (18.6 kg ha−1) for soybean was significantly higher than that of the other treatments. The above-ground-P uptake (AGPU) in SMN, for both corn and soybean, was significantly higher than that of the other five treatments. The soil test P (STP) presented clear stratification, concentrating in the top 30 cm soil depth after 10 years of application. The contents of STP with LMN and SMN increased from 7.1 mg P kg−1 to 12.4 and 45.5 mg P kg−1, respectively. The sum of STP mass (0–30 cm) with LMP (31.6 kg ha−1) was largely identical to that with CFP (30.1 kg ha−1), however, with SMN (173.7 kg ha−1), it was significantly higher than the rest of the treatments. Manure P source availability coefficients were averaged at 1.06 and 1.07 for LMP and SMP, respectively. The addition of phosphorus-based liquid or solid swine manure can overcome the drawback of traditional N-based applications by potentially reducing the adverse impact on water quality while sustaining crop agronomic production.

Mungbean (Vignaradiata L. Wilczek) is an early maturing legume grown predominantly in Asia for its protein-rich seeds. P deficiency can lead to several physiological disorders which ultimately result in a low grain yield in mungbean. The genetic dissection of PUpE (Puptake efficiency) and PUtE (P utilization efficiency) traits are essential for breeding mungbean varieties with a high P uptake and utilization efficiency. The study involves an association mapping panel consisting of 120 mungbean genotypes which were phenotyped for total dry weight, P concentration, total P uptake, and P utilization efficiency under low P (LP) and normal P (NP) conditions in a hydroponic system. A genotyping-by-sequencing (GBS) based genome-wide association study (GWAS) approach was employed to dissect the complexity of PUpE and PUtE traits at the genetic level in mungbean. This has identified 116 SNPs in 61 protein-coding genes and of these, 16 have been found to enhance phosphorous uptake and utilization efficiency in mungbeans. We identified six genes with a high expression (VRADI01G04370, VRADI05G20860, VRADI06G12490, VRADI08G20910, VRADI08G00070 and VRADI09G09030) in root, shoot apical meristem and leaf, indicating their role in the regulation of P uptake and utilization efficiency in mungbean. The SNPs present in three genes have also been validated using a Sanger sequencing approach.

In calcareous soils, phosphorus (P) availability to plant is impaired due to the formation of insoluble complexes with calcium and magnesium. Therefore, this study was executed to compare the P use efficiency (PUE) of four different P sources [rock phosphate (RP), acidulated rock phosphate (ARP), single super phosphate (SSP) and di ammonium phosphate (DAP)] alone or pre-treated with organic amendments (farm yard manure (FYM) enriched compost, simple compost and humic acid (HA)) along with control in maize crop under calcareous soils. All treatments irrespective of P sources received 90 kg P2O5 ha−1. Phosphorus application regardless of its sources and combination with organic amendments significantly improved maize growth, yield as well as P uptake and PUE. Rock phosphate when applied alone was recorded inferior but its performance significantly improved with compost or its pre-addition with FYM and HA, that further enhanced upon acidulation. Maize grain yield increased by 21, 22.2, 67.9 and 94% with RP, ARP, ARP enriched compost and ARP+ compost respectively, over control. Similarly, PUE of DAP improved from 31.7 to 43.1 and 39 with sample and enriched compost correspondingly. Post-harvest soil and grain P were at par for SSP, ARP and DAP alone or in conjugation with organic amendments when averaged across the amendments. These results suggested that pretreatment of P sources with organic amendments is an economical and more feasible approach to improve maize yield and PUE. Moreover, on-farm acidulation of RP may give at par results with SSP and DAP with cheaper rate and hence recommended for P management in maize in alkaline calcareous soils.

Summary The availability of orthophosphate (Pi) is a key determinant of crop productivity because its accessibility to plants is poor due to its conversion to unavailable forms. Weed's competition for this essential macronutrient further reduces its bio‐availability. To compensate for the low Pi use efficiency and address the weed hazard, excess Pi fertilizers and herbicides are routinely applied, resulting in increased production costs, soil degradation and eutrophication. These outcomes necessitate the identification of a suitable alternate technology that can address the problems associated with the overuse of Pi‐based fertilizers and herbicides in agriculture. The present review focuses on phosphite (Phi) as a novel molecule for its utility as a fertilizer, herbicide, biostimulant and biocide in modern agriculture. The use of Phi‐based fertilization will help to reduce the consumption of Pi fertilizers and facilitate weed and pathogen control using the same molecule, thereby providing significant advantages over current orthophosphate‐based fertilization.

Phosphorus (P) is a non-renewable resource highlighting the significance of developing and using alternative P sources for a sustainable agriculture. The work aims to compare the effects of different organic amendments (OA) and a mineral P fertiliser as reference on P use efficiency by the crop, and on P losses to runoff waters and eroded sediments. A two-year field trial was conducted in a Dystric Regosol with Lolium sp. Treatments were: cattle manure compost (CM), solid fraction of swine (SS) and duck (DS) slurries and triple superphosphate (TSP), each applied at 50 kg P ha−1 year−1. Olsen P (mg P kg−1) increased from ≈ 19 at the beginning to ≈ 30 (TSP, CM), 45 (SS) and 62 (DS) after the experiment. Most of applied P remained in soil, between 92% (SS) and 96% (TSP), plant uptake ranged from 5% (CM) to 3.5% (TSP) and total P loss in runoff and sediments ranged between 0.2% (CM) and 4% (SS). OA increased P-use efficiency by the ryegrass crop compared with mineral P fertilizer. Composted cattle man...

Changes in the levels of plant metabolites in response to nutrient deficiency is indicative of how plants utilize scarce resources. In this study, changes in the metabolite profile of roots and shoots of wheat genotypes differing in phosphorus use efficiency (PUE) was investigated. Under low P supply and at 28 days after sowing (DAS), the wheat breeding line, RAC875 (P efficient) produced 42% more shoot biomass than the wheat variety, and Wyalkatchem (P inefficient). Significant changes in the metabolite profile in leaves and roots were observed under low P supply and significant genotypic variation was evident. Under low P supply, an increase in raffinose and 1-kestose was evident in roots of both wheat genotypes, with RAC875 accumulating more when compared to Wyalkatchem. There was no significant increase in raffinose and 1-kestose in leaves when plants were grown under P deficiency. P deficiency had no significant impact on the levels of sucrose, maltose, glucose and fructose in both genotypes, and while phosphorylated sugars (glucose-6-P and fructose-6-P) remained unchanged in RAC875, in Wyalkatchem, glucose-6-P significantly decreased in roots, and fructose-6-P significantly decreased in both leaves and roots. Glycerol-3-P decreased twofold in roots of both wheat genotypes in response to low P. In roots, RAC875 exhibited significantly lower levels of fumarate, malate, maleate and itaconate than Wyalkatchem, while low P enhanced organic acid exudation in RAC875 but not in Wyalkatchem. RAC875 showed greater accumulation of aspartate, glutamine and β-alanine in leaves than Wyalkatchem under low P supply. Greater accumulation of raffinose and 1-kestose in roots and aspartate, glutamine and β-alanine in leaves appears to be associated with enhanced PUE in RAC875. Glucose-6-P and fructose-6-P are important for glycolysis, thus maintaining these metabolites would enable RAC875 to maintain carbohydrate metabolism and shoot biomass under P deficiency. The work presented here provides evidence that differences in metabolite profiles can be observed between wheat varieties that differ in PUE and key metabolic pathways are maintained in the efficient genotype to ensure carbon supply under P deficiency.

Established fertilizer recommendations for wheat is urgently required to enhance the application efficiency of commercial phosphorus (P) fertilizers. This study evaluated the effect of inorganic P combined with some organic supplements i.e., citric acid (CA) or pigeon manure juice (PMJ), on alkaline-calcareous soil as well as plant measurements and phosphorus efficiency parameters of wheat (Triticum durum ’Boussalem’). Different concentrations of P in solution i.e., 0.05, 0.10, 0.15, 0.20, and 0.40 mg l−1, were worked out theoretically using the Freundlich model. A greenhouse study was conducted on a permanent layout with three replicates. As a result, phosphorus in the control was 0.493 mg P pot−1. However, in amended pots with organic substances, the averages of P uptake were 0.701 and 0.785 mg P pot−1, respectively for PMJ and CA treatments. A lower P requirement of 0.195 and 0.245 mg P l−1 may be required in CA and PMJ treatments, compared to the control treatments (0.345 mg P l−1). In addition, the phosphorus absorption efficiency (PAE) was higher in the CA and PMJ treatments. So, it is recommended to apply P fertilizers with poultry manure juice as an alternative solution in order to improve the efficiency of inorganic P fertilizers and consequently reduce their application rates in alkaline calcareous soils.

Rational regulation of phosphorus (P) use in the soil&ndash, rhizosphere&ndash, plant system is challenging in the development of sustainable, intensive, and healthy agriculture. Rational maize (Zea mays L.) based intercropping with legumes/oilseed rape across six experimental sites from 2008 to 2017 proved advantageous over monoculture in terms of both maize biomass production and P uptake. The partial land equivalent ratio (PLER) for P uptake by intercropped maize averaged from 0.58 to 0.92, which was significantly higher than that for biomass production (0.51&ndash, 0.78), indicating that the advantage of P acquisition by intercropped maize was superior to that of biomass accumulation. It was the excessive accumulation of P in intercropped maize compared to monoculture, especially higher P concentrations in grains that led to the superior P acquisition advantage and luxury absorption of P. P concentrations in maize grains were significantly increased from 1.89&ndash, 2.91 mg kg&minus, 1 in monoculture to 2.09&ndash, 3.65 mg kg&minus, 1, in intercropping, by 8.3%&ndash, 25.5%. The plant internal P use efficiency of maize was significantly decreased from the initial 411.7&ndash, 775.7 kg kg&minus, 1 in monoculture to 345.7&ndash, 710.4 kg kg&minus, 1 in intercropping by 4.9%&ndash, 16.0%, and 100 kg maize grain P quantities were significantly increased from 0.25&ndash, 0.46 kg to 0.27&ndash, 0.54 kg by 7.0%&ndash, 17.4%. Rational fertilizer P input maximized maize yields and P use without decreasing the interspecific ecological advantages and harvest indexes of grain yields and P. These findings promoted better understanding of P allocation status within maize plants, and yield and P acquisition advantages through the exploitation of the biological potential of plants for the efficient utilization of P resources in diverse species combinations.

Phosphorus (P) recycling and carbon partitioning are crucial determinants of P-use efficiency and grain yield in maize (Zea mays), while a full understanding of how differences in P availability/plant P status affect these two processes underlying yield formation remains elusive. Field experiments were conducted for 3 years to investigate the maize growth, P remobilization, and carbohydrate accumulation in leaves and developing ears of plants receiving low to high P inputs. In plots that 75 kg P2O5 ha-1 and above was applied (corresponding to 7.5 mg kg-1 and higher Olsen-P concentration in 0–20 cm soil layer), no additional response occurred in leaf area, ear growth, and grain yield. Despite the higher P uptake with P fertilization above this threshold, the lack of additional plant growth and yield resulted in decreased P-use efficiency. Regardless of P application rates, P remobilization to the ear during the first half of the grain filling phase preferentially came from the stem (50–76%) rather than from leaves (30–44%), and with a greater proportion in the inorganic P (Pi) form over organic P fractions. Leaf photosynthesis was maintained under P-limiting conditions due to the greater P investment in organic P pools than Pi. More and larger starch granules were found in the bundle sheath cells at silking or 21 days after silking (DAS) than under P-sufficient conditions. The amount of total carbohydrate production and export was lower in the P-deficient plants than the high-P plants, corresponding to decreased leaf size and lifespan. Nonetheless, similar or significantly greater starch levels were observed in both cob and kernels at silking and 21 DAS, implying there was an adequate carbohydrate supply to the developing ears under the diminished kernel sink of the P starvation. In addition, there was a strong correlation between the accumulation rates of carbon and remobilized P in the developing kernels, as well as between carbon and total P. Overall, the results indicated that diminished sink size and lower capacity of carbon deposition may limit yield formation in P-deficient maize, which in turn imposes a feedback regulation on reducing carbon and P remobilization from source leaves. An integrated framework considering post-silking P recycling and carbon partitioning in maize and their effects on grain yield has been proposed.

Surface temperature in the ocean is projected to be elevated and more variable in the future, which will interact with other environmental changes like reduced nutrient supplies. To explore these multiple stressor relationships, we tested the influence of thermal variation on the key marine diazotrophic cyanobacterium Trichodesmium erythraeum GBRTRLI101 as a function of the limiting nutrient phosphorus (P). Two constant temperature treatments represented current winter (22°C) and summer (30°C) mean values. Three variable temperature treatments fluctuated around the constant control values: Mean 22°C, either ± 2°C or ± 4°C; and mean 30°C ± 2°C. Each thermal treatment was grown under both P-replete (10 μmol/L) and P-limiting conditions (0.2 μmol/L). Effects of thermal variability on Trichodesmium were mainly found in the two winter variable temperature treatments (22°C ± 2°C or ± 4°C). P availability affected growth and physiology in all treatments and had significant interactions with temperature. P-replete cultures had higher growth and nitrogen and carbon fixation rates in the 22°C constant control, than in the corresponding variable treatments. However, physiological rates were not different in the P-replete constant and variable treatments at 30°C. In contrast, in P-limited cultures an advantage of constant temperature over variable temperature was not apparent. Phosphorus use efficiencies (PUE, mol N or C fixed h-1 mol cellular P-1) for nitrogen and carbon fixation were significantly elevated under P-limited conditions, and increased with temperature from 22 to 30°C, implying a potential advantage in a future warmer, P-limited environment. Taken together, these results imply that future increasing temperature and greater thermal variability could have significant feedback interactions with the projected intensification of P-limitation of marine N2-fixing cyanobacteria.

Surface temperature in the ocean is projected to be elevated and more variable in the future, which will interact with other environmental changes like reduced nutrient supplies. To explore these multiple stressor relationships, we tested the influence of thermal variation on the key marine diazotrophic cyanobacterium Trichodesmium erythraeum GBRTRLI101 as a function of the limiting nutrient phosphorus (P). Two constant temperature treatments represented current winter (22°C) and summer (30°C) mean values. Three variable temperature treatments fluctuated around the constant control values: Mean 22°C, either ± 2°C or ± 4°C; and mean 30°C ± 2°C. Each thermal treatment was grown under both P-replete (10 μmol/L) and P-limiting conditions (0.2 μmol/L). Effects of thermal variability on Trichodesmium were mainly found in the two winter variable temperature treatments (22°C ± 2°C or ± 4°C). P availability affected growth and physiology in all treatments and had significant interactions with temperature. P-replete cultures had higher growth and nitrogen and carbon fixation rates in the 22°C constant control, than in the corresponding variable treatments. However, physiological rates were not different in the P-replete constant and variable treatments at 30°C. In contrast, in P-limited cultures an advantage of constant temperature over variable temperature was not apparent. Phosphorus use efficiencies (PUE, mol N or C fixed h-1 mol cellular P-1) for nitrogen and carbon fixation were significantly elevated under P-limited conditions, and increased with temperature from 22 to 30°C, implying a potential advantage in a future warmer, P-limited environment. Taken together, these results imply that future increasing temperature and greater thermal variability could have significant feedback interactions with the projected intensification of P-limitation of marine N2-fixing cyanobacteria.

Fertilizers and herbicides are two major components in the agriculture system for achieving crop productivity. Massive use of orthophosphate fertilizers and herbicides poses threats to phosphate reserves and aids the evolution of herbicide tolerant weed biotypes. Phosphite (Phi), a phosphate analog, has been proposed as more beneficial than traditionally used phosphate fertilizers and herbicides in the agriculture. We developed phoA overexpressing transgenic rice that minimizes the phosphate loss and contributes to weed management in the agriculture. The phoA rice lines showed improved root, shoot length and total biomass production under phosphite conditions. Additionally, the complete phenotype and productivity of phoA lines under the phosphite treatment attained was similar to that of plants under phosphate sufficient condition. The Phi metabolizing properties of the phoA overexpressed lines improved under the Phi application and phi treatment enabled controlling of weeds without compromising the yield of transgenic rice plants. Our results indicated that phoA alone or in combination with other Phi metabolizing gene(s) can possibly be used as an effective ameliorating system for improving crop plants for phi-based fertilization and weed management strategy in the agriculture.

Changes in the levels of plant metabolites in response to nutrient deficiency is indicative of how plants utilize scarce resources. In this study, changes in the metabolite profile of roots and shoots of wheat genotypes differing in phosphorus use efficiency (PUE) was investigated. Under low P supply and at 28 days after sowing (DAS), the wheat breeding line, RAC875 (P efficient) produced 42% more shoot biomass than the wheat variety, and Wyalkatchem (P inefficient). Significant changes in the metabolite profile in leaves and roots were observed under low P supply and significant genotypic variation was evident. Under low P supply, an increase in raffinose and 1-kestose was evident in roots of both wheat genotypes, with RAC875 accumulating more when compared to Wyalkatchem. There was no significant increase in raffinose and 1-kestose in leaves when plants were grown under P deficiency. P deficiency had no significant impact on the levels of sucrose, maltose, glucose and fructose in both genotypes, and while phosphorylated sugars (glucose-6-P and fructose-6-P) remained unchanged in RAC875, in Wyalkatchem, glucose-6-P significantly decreased in roots, and fructose-6-P significantly decreased in both leaves and roots. Glycerol-3-P decreased twofold in roots of both wheat genotypes in response to low P. In roots, RAC875 exhibited significantly lower levels of fumarate, malate, maleate and itaconate than Wyalkatchem, while low P enhanced organic acid exudation in RAC875 but not in Wyalkatchem. RAC875 showed greater accumulation of aspartate, glutamine and β-alanine in leaves than Wyalkatchem under low P supply. Greater accumulation of raffinose and 1-kestose in roots and aspartate, glutamine and β-alanine in leaves appears to be associated with enhanced PUE in RAC875. Glucose-6-P and fructose-6-P are important for glycolysis, thus maintaining these metabolites would enable RAC875 to maintain carbohydrate metabolism and shoot biomass under P deficiency. The work presented here provides evidence that differences in metabolite profiles can be observed between wheat varieties that differ in PUE and key metabolic pathways are maintained in the efficient genotype to ensure carbon supply under P deficiency.

Aims\ud Potato (Solanum tuberosum L.) has a large phosphorus (P)-fertiliser requirement. This is thought to be due to its inability to acquire P effectively from the soil. This work tested the hypothesis that early proliferation of its root system would enhance P acquisition, accelerate canopy development, and enable greater yields.\ud \ud Methods\ud Six years of field experiments characterised the relationships between (1) leaf P concentration ([P]leaf), tuber yield, and tuber P concentration ([P]tuber) among 27 Tuberosum, 35 Phureja and 4 Diploid Hybrid genotypes and (2) juvenile root vigour, P acquisition and tuber yield among eight Tuberosum genotypes selected for contrasting responses to P-fertiliser.\ud \ud Results\ud Substantial genetic variation was observed in tuber yield, [P]leaf and [P]tuber. There was a strong positive relationship between tuber yields and P acquisition among genotypes, whether grown with or without P-fertiliser. Juvenile root vigour was correlated with accelerated canopy development and both greater P acquisition and tuber biomass accumulation early in the season. However, the latter relationships became weaker during the season.\ud \ud Conclusions\ud Increased juvenile root vigour accelerated P acquisition and initial canopy cover and, thereby, increased tuber yields. Juvenile root vigour is a heritable trait and can be selected to improve P-fertiliser use efficiency of potato.

Phosphorus (P) deficiency is one of the major limiting factors for crop productivity. The yield of rice (Oryza sativa L.) is severely limited by phosphorus deficiency. An attempt has been made in this study to identify P deficiency responsive differentially expressed proteins of rice through analysis of leaf proteome of contrasting P-responsive rice cultivars under P deficiency conditions because genetic variability has been found in the rice cultivars for adaptive response to P deficiency and a controlled regulatory system is involved in the P deficiency adaptation response. Phosphorus-efficient (cv. Panvel) and P-inefficient (cv. Nagina 22) rice cultivars were hydroponically grown in the nutrient medium under control environmental conditions at low-P level (2.0 &micro, M) and optimum-P level (320 &micro, M) treatments. Expression patterns of the proteins of the leaves of both the cultivars were analyzed in 30-day-old plants. The identification of these proteins through mass spectrometry and MASCOT software (Matrix Science Inc., Boston, USA) revealed that these differentially expressed proteins were homologous to known functional proteins involved in energy metabolism, biosynthesis, photosynthesis, signaling, protein synthesis, protein folding, phospholipid metabolism, oxidative stress, transcription factors, and phosphorus metabolism. It has been observed that rice cultivars responded differently to low-P treatment through modification in protein expressions pattern to maintain the growth of the plants. Therefore, the expression patterns of proteins were different in both of the cultivars under low-P treatment. Higher potential of protein stability, stress tolerance, osmo-protection, and regulation of phosphorus uptake was observed in cv. Panvel than cv. Nagina 22. This study could help to unravel the complex regulatory process that is involved in adaptation to P deficiency in rice.

Background Phosphorus (P) deficiency limits crop production worldwide. Crops differ in their ability to acquire and utilise the P available. The aim of this study was to determine root traits (root exudates, root system architecture (RSA), tissue-specific allocation of P, and gene expression in roots) that (a) play a role in P-use efficiency and (b) contribute to large shoot zinc (Zn) concentration in Brassica oleracea. Results Two B. oleracea accessions (var. sabellica C6, a kale, and var. italica F103, a broccoli) were grown in a hydroponic system or in a high-throughput-root phenotyping (HTRP) system where they received Low P (0.025 mM) or High P (0.25 mM) supply for 2 weeks. In hydroponics, root and shoot P and Zn concentrations were measured, root exudates were profiled using both Fourier-Transform-Infrared spectroscopy and gas-chromatography-mass spectrometry and previously published RNAseq data from roots was re-examined. In HTRP experiments, RSA (main and lateral root number and lateral root length) was assessed and the tissue-specific distribution of P was determined using micro-particle-induced-X-ray emission. The C6 accession had greater root and shoot biomass than the F103 accession, but the latter had a larger shoot P concentration than the C6 accession, regardless of the P supply in the hydroponic system. The F103 accession had a larger shoot Zn concentration than the C6 accession in the High P treatment. Although the F103 accession had a larger number of lateral roots, which were also longer than in the C6 accession, the C6 accession released a larger quantity and number of polar compounds than the F103 accession. A larger number of P-responsive genes were found in the Low P treatment in roots of the F103 accession than in roots of the C6 accession. Expression of genes linked with “phosphate starvation” was up-regulated, while those linked with iron homeostasis were down-regulated in the Low P treatment. Conclusions The results illustrate large within-species variability in root acclimatory responses to P supply in the composition of root exudates, RSA and gene expression, but not in P distribution in root cross sections, enabling P sufficiency in the two B. oleracea accessions studied.

Improving phosphorus use efficiency (PUE) in wheat (Triticum aestivum L.) can reduce dependence on P fertilizer. The objectives of this research were to: 1) evaluate the genetic diversity in a population of synthetic hexaploid wheat derived lines (n=194); 2) identify genomic regions in wheat related to PUE, and 3) to assess the suitability of using this plant material in a breeding program. Three field trials were conducted under 0 kg ha-1 and 125 kg ha-1 monoammonium phosphate over two years. It was determined that significant variation exists in this population for P-related traits, root morphology and agronomic traits. Using 6 904 polymorphic SNP markers, 32 markers were identified for agronomic traits, three markers for average root diameter, and 7 markers for P-use related traits. Superior genotypes were identified that could be used as parents in wheat breeding programs for improved PUE. Natural Sciences and Engineering Research Council (NSERC)

When urban waste is not separately collected its phosphorus content cannot be recovered. The production of phosphorus-based fertilisers from urban waste could generate phosphorus added-value products, reduce environmental impacts from waste disposal and lower the consumption of virgin raw materials in the fertiliser industry. The main objective of this work was to evaluate the short-term agronomic value of a phosphorus fertiliser, which has the same chemical composition and mineralogical structure as struvite, but is artificially produced using phosphorus recovered from the anaerobically digested organic fraction of municipal solid waste (herein referred to as “secondary struvite”). To evaluate the release of phosphorus forms over time a 30 d incubation experiment was performed. Then the cultivation of rye (Secale cereale L.) was done in pot scale during 45 d to assess the phosphorus phytoavailability and the agronomic potential of secondary struvite, when compared with the commercial mineral fertiliser, single superphosphate. This work contributes to fill a knowledge gap about the effects of this secondary struvite as a source of phosphorus on soil phosphorus forms as well as on phosphorus’ soil and plant availability. At the end of the incubation experiment, a similar distribution of phosphorus forms in soil for both secondary struvite and single superphosphate was observed; however, the soil Olsen phosphorus was significantly higher in the soils fertilised using secondary struvite than in those fertilised by single superphosphate, which indicates that secondary struvite provided a higher amount of immediately phytoavailable phosphorus. The shoot biomass production (1.7 g dry-matter kg 1 soil) and the agronomic efficiency (66 g drymatter g 1 phosphorus) were similar for both fertilisers. But the crop's phosphorus uptake and the apparent phosphorus recovery were higher (5.9 mg phosphorus kg 1 soil and 45%) in the secondary struvite treatment than in the single superphosphate treatment (4.7 mg phosphorus kg 1 soil and 36%). The results suggest that the secondary struvite can be used as a phosphorus fertiliser and lower rates of the secondary struvite are required to achieve the same agronomic efficiency as the single superphosphate. The authors would like to thank Marta Solipa Batista, for laboratorial support and analyses, as well as Benjamin Colo and Joana Lapao for the English revisions. This work has been funded by project 0340-SYMBIOSIS-3-E co-funded by FEDER “Fundo Europeu de Desenvolvimento Regional” through Interreg V-A Espana- Portugal (POCTEP) 2014e2020. Celia Dias-Ferreira and Veronica Oliveira have been funded through FCT “Fundação para a Ciência e para a Tecnologia” by POCH e Programa Operacional Capital Humano within ESF e European Social Fund and by national funds from MCTES (SFRH/BPD/100717/2014; SFRH/BD/115312/2016). info:eu-repo/semantics/publishedVersion

Objectives Phosphorus (P) deficiency is a major limitation to plant growth. Under several abiotic stresses, including P deficiency, upland cereal crops, such as maize, are well known to develop lysigenous aerenchyma, a root tissue containing gas spaces. Contrary to upland species, rice develops aerenchyma constitutively. Nevertheless, aerenchyma in rice is also enhanced by several abiotic stresses, including P deficiency. However, studies are limited and genotypic differences are not clear. Results The formation of inducible aerenchyma in response to P deficiency was evaluated in two rice genotypes, DJ123 and Nerica4. Whole root porosity increased for both genotypes in low P conditions, but was more pronounced in DJ123. Direct aerenchyma measurements, at 20 and 30 mm from the seminal root tip, revealed that aerenchyma in low P conditions was only enhanced in DJ123. These results confirm that P deficiency in rice induces the formation of aerenchyma, and further show that genotypic differences exist. Interestingly, DJ123 is considered tolerant to P deficiency, whereas Nerica4 is sensitive, pointing towards a potential role of aerenchyma in tolerance to P deficiency. Electronic supplementary material The online version of this article (10.1186/s13104-018-3179-y) contains supplementary material, which is available to authorized users.

Water and phosphorus (P) are essential resources for crop production, yet both are increasingly limited, threatening global food security. Soil drying and re-wetting (DRW) has reportedly increased P availability in numerous soils, whilst intermittent irrigation that applies less water than conventional full irrigation can maintain crop yields. To test the hypothesis that DRW could release P at soil water potentials (SWPs) that can support plant growth, thereby increasing crop P use efficiency and yields, experiments at different scales aimed to evaluate P release and plant uptake. Laboratory studies using three low-P UK soils determined that available P (sodium bicarbonate extractable P) significantly increased (by 4-7 mg kg-1) as SWP decreased (to a minimum of -212 MPa). A significant change point (releasing 2 mg P kg-1) occurred at -2.9 MPa. A pot study showed that surface soil drying to this change point did not increase P availability over one or two DRW cycles, suggesting laboratory results could not be scaled up spatially and temporally. Initially air-drying (to -38 MPa) and re-wetting soil prior to planting Brachypodium distachyon in pots significantly increased available P at transplanting (by 1 mg kg-1) and doubled grain yields independent of P fertiliser application. In a field trial in central Madagascar in low-P, highly P-fixing soil, applying alternate wetting and drying (AWD) or post-anthesis soil drying to Oryza sativa hardly altered P uptake or yields. Thus, DRW increased P availability and yields in pots, but plants did not benefit during a cropping cycle in the field. Applying P fertiliser (10 or 25 kg ha-1) had a greater effect than AWD, with optimal harvest index (HI) and P use efficiency (PUE) at the intermediate rate. Further research to determine locally-relevant management techniques, stimulating P release at appropriate spatial and temporal scales to allow plant uptake, is urgently required.

The application of microbial inoculants (biofertilizers) is a promising technology for future sustainable farming systems in view of rapidly decreasing phosphorus stocks and the need to more efficiently use available nitrogen (N). Various microbial taxa are currently used as biofertilizers, based on their capacity to access nutrients from fertilizers and soil stocks, to fix atmospheric nitrogen, to improve water uptake or to act as biocontrol agents. Despite the existence of a considerable knowledge on effects of specific taxa of biofertilizers, a comprehensive quantitative assessment of the performance of biofertilizers with different traits such as phosphorus solubilization and N fixation applied to various crops at a global scale is missing. We conducted a meta-analysis to quantify benefits of biofertilizers in terms of yield increase, nitrogen and phosphorus use efficiency, based on 171 peer reviewed publications that met eligibility criteria. Major findings are: (i) the superiority of biofertilizer performance in dry climates over other climatic regions (yield response: dry climate +20.0 ± 1.7%, tropical climate +14.9 ± 1.2%, oceanic climate +10.0 ± 3.7%, continental climate +8.5 ± 2.4%); (ii) meta-regression analyses revealed that yield response due to biofertilizer application was generally small at low soil P levels; efficacy increased along higher soil P levels in the order arbuscular mycorrhizal fungi (AMF), P solubilizers, and N fixers; (iii) meta-regressions showed that the success of inoculation with AMF was greater at low organic matter content and at neutral pH. Our comprehensive analysis provides a basis and guidance for proper choice and application of biofertilizers., Frontiers in Plant Science, 8, ISSN:1664-462X