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Abstract 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.

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.

Small-scale aquaculture systems can contribute significantly to food and nutritional security, poverty alleviation, and rural development, especially in developing countries. However, the intensification of aquaculture systems often has negative environmental outcomes. The adoption of diversification practices (e.g. polyculture, pond-dike cropping (PDC)) and better management practices (BMPs) has been identified as a possible approach to intensify sustainably small-scale aquaculture production. This study assesses the sustainability outcomes of the adoption of diversification practices and BMPs in small-scale production models. We focus on Myanmar, a developing country characterized by a rapidly expanding small-scale aquaculture sector. We analyze 624 household surveys with small-scale aquaculture producers in central and northern Myanmar. We estimate the effects of diversification practices and BMPs on different sustainability outcomes, namely economic outcomes (i.e. aquaculture yield and benefit-cost ratio), environmental outcomes (i.e. nitrogen and phosphorus use efficiency), and food security outcomes (i.e. fish self-consumption and household dietary diversity) through linear mixed-effects models. Our results reveal that diversified production models (whether integrating or not integrating BMPs) could have significant positive effects on economic and food security outcomes, as well as phosphorus use efficiency, compared to ‘unimproved monoculture’. However, such production models do not seem to have any major effect on nitrogen use efficiency. The adoption of BMPs on diversified production models seems to have little (if any) added effect on any of the studied sustainability outcomes, which suggests the need to improve existing BMPs or even develop new BMPs fit for Myanmar’s context. These findings have implications about the possible contribution of diversification practices and BMPs for enabling sustainable intensification in small-scale aquaculture settings in Myanmar, and other rural developing contexts.

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.

The continued supply of phosphate fertilizers that underpin global food production is an imminent crisis. The rock phosphate deposits on which the world depends are not only finite, but some are contaminated, and many are located in geopolitically unstable areas, meaning that fundamental changes will have to take place in order to maintain food production for a growing global population. No single solution exists, but a combination of approaches to phosphorus management is required not only to extend the lifespan of the remaining non-renewable rock phosphate reserves, but to result in a more efficient, sustainable phosphorus cycle. Solutions include improving the efficiency of fertilizer applications to agricultural land, alongside a better understanding of phosphorus cycling in soil-plant systems, and the interactions between soil physics, chemistry and biology, coupled with plant traits. Opportunities exist for the development of plants that can access different forms of soil phosphorus (e.g., organic phosphorus) and that use internal phosphorus more efficiently. The development of different sources of phosphorus fertilizers are inevitably required given the finite nature of the rock phosphate supplies. Clear opportunities exist, and it is now important that a concerted effort to make advances in phosphorus use efficiency is prioritized.

Vegetable production systems involve high rates of chemical and organic fertilizer applications, leading to significant P accumulation in vegetable soils, as well as a decrease in P use efficiency (PUE), which is one of the key limiting factors in vegetable production. This review introduces the vegetable production systems in China and their fertilization status, and analyzes probable causes of overfertilization of vegetable fields. Poorly developed root systems and high P demand have led to the need to maintain much higher available P concentrations in the root zone for regular growth of vegetables, which might necessitate higher phosphate fertilizer input than the plants require. Research on strategies to improve vegetable PUE and the mechanisms of these strategies are summarized in this review. Increasing the P uptake by vegetables by supplying P during the critical growth stage and effectively utilizing the accumulated P by optimizing the C:P ratio in soils can substantially increase PUE. These advances will provide a basis for improving PUE and optimizing phosphate fertilizer applications in vegetable production through regulatory measures. In addition, some policies are recommended that could ensure the safety of vegetables and improve product quality. This review also aims to improve understanding of P cycling in vegetable fields and assist in the development of best practices to manage P reserves globally.

Phosphorus is the second most important macronutrient after nitrogen and it has many vital functions in the life of plants. Most soils have a low available P content, which has become a key limiting factor for increasing crop production. Also, low P use efficiency (PUE) of crops in conjunction with excessive application of P fertilizers has resulted in serious environmental problems. Thus, dissecting the genetic architecture of crop PUE, mining related quantitative trait loci (QTL) and using molecular breeding methods to improve high PUE germplasm are of great significance and serve as an efficient approach for the development of sustainable agriculture. In this review, molecular and phenotypic characteristics of maize inbred lines with high PUE, related QTL and genes as well as low-P responses are summarized. Based on this, a breeding strategy applying genomic selection as the core, and integrating the existing genetic information and molecular breeding techniques is proposed for breeding high PUE maize inbred lines and hybrids.

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.

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.

Reasonable soybean-maize intercropping mode can effectively promote soil phosphorus turnover and crop phosphorus absorption, and reduce phosphorus fertilizer input. To optimize phosphorus (P)-use efficiency in soybean/maize intercropping system, we intercropped two genotypes of soybean with maize to investigate the rhizosphere processes and mechanisms underlying soil biological P fractions and crop P uptake. The results showed that intercropping significantly depleted the rhizosphere soluble inorganic P (CaCl 2 -P) content in soybean genotype Yuechun 03-3, without impact on the P fractions in the rhizosphere of soybean Essex. Similarly, intercropping significantly increased biomass and P uptake of soybean genotype Yuechun 03-3 by 42.2% and 46.9%, respectively, compared to monoculture. However, it did not affect P uptake and biomass of soybean Essex and maize. Intercropping significantly increased both the total root length and the quantity of root exudates in Yuechun 03-3 by 19.7% and 138.1%, respectively. There was a significant positive correlation between P uptake and total root length in Yuechun 03-3, while a significant negative correlation between soluble inorganic P content and P uptake. In summary, intercropping of soybean and maize exhibited noticeable genotype differences in its impact on soil P fractions and crop P uptake. Intercropping has the potential to improve soybean P uptake and rhizosphere P turnover, mainly by increasing root length and root exudates of P-efficient genotype. The study would provide scientific evidence for optimizing the pairing of soybean and maize varieties in intercropping systems, thereby enhancing phosphorus utilization efficiency and reducing fertilizer inputs.

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.

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. [ABSTRACT FROM AUTHOR]

Phosphorus (P) deficiency is a limiting factor for sustainable rice (Oryza sativa L.) production. However, little is known about how rice varieties that differ in tolerance to low P perform under water‐saving irrigation. In this study, we characterized the responses of two rice varieties, ZD88 that has a weak tolerance to low soil P and YJ2 that has a strong tolerance to low soil P to two irrigation regimes under both optimal P (NP, 46.9 mg/kg Olsen‐P) and low P (LP, 6.8 mg/kg Olsen‐P). The first irrigation regime involved continuous flooding (CF), while the second involved alternate wetting and moderate soil drying (AWD). The study was conducted in plants grown in pot over two years. YJ2 exhibited stronger tolerance to LP than ZD88 under both irrigation regimes. Compared to CF, plants grown with AWD produced higher grain yields and had increased phosphorus translocation efficiencies, as well as higher metabolic phosphorus efficiencies and increased phosphorus harvest index values. The water use efficiencies of the two rice varieties were increased under both NP and LP under AWD conditions. The AWD regime also resulted in higher shoot dry weights and increased photosynthesis rates under LP compared with CF. Moreover, the remobilization of non‐structural carbohydrates from stems to the grain was also increased under the AWD regime, together with higher activities of sucrose‐phosphate synthase, sucrose synthase and peroxidases and increased abscisic acid contents in grains. Root dry weights and root to shoot ratios were also increased under AWD conditions, together with increased root acid phosphatase activities. Taken together, these results demonstrate that the AWD regime benefits rice production under LP environment. [ABSTRACT FROM AUTHOR]

Abstract Phosphorus (P) deficiency is a limiting factor for sustainable rice (Oryza sativa L.) production. However, little is known about how rice varieties that differ in tolerance to low P perform under water‐saving irrigation. In this study, we characterized the responses of two rice varieties, ZD88 that has a weak tolerance to low soil P and YJ2 that has a strong tolerance to low soil P to two irrigation regimes under both optimal P (NP, 46.9 mg/kg Olsen‐P) and low P (LP, 6.8 mg/kg Olsen‐P). The first irrigation regime involved continuous flooding (CF), while the second involved alternate wetting and moderate soil drying (AWD). The study was conducted in plants grown in pot over two years. YJ2 exhibited stronger tolerance to LP than ZD88 under both irrigation regimes. Compared to CF, plants grown with AWD produced higher grain yields and had increased phosphorus translocation efficiencies, as well as higher metabolic phosphorus efficiencies and increased phosphorus harvest index values. The water use efficiencies of the two rice varieties were increased under both NP and LP under AWD conditions. The AWD regime also resulted in higher shoot dry weights and increased photosynthesis rates under LP compared with CF. Moreover, the remobilization of non‐structural carbohydrates from stems to the grain was also increased under the AWD regime, together with higher activities of sucrose‐phosphate synthase, sucrose synthase and peroxidases and increased abscisic acid contents in grains. Root dry weights and root to shoot ratios were also increased under AWD conditions, together with increased root acid phosphatase activities. Taken together, these results demonstrate that the AWD regime benefits rice production under LP environment.

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.

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.

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.

Calcareous soils, characterized by a higher pH, are frequent in the North West of Tunisia. Large concentrations of calcium carbonate in calcareous soils result in accumulation of high levels of bicarbonate ions, which complex with phosphate, resulting in phosphorus deficiency (induced P deficiency) for plants. The impact of calcareous soil on plant growth, photosynthetic activity and acid phosphatase activity was explored in two lines of Medicago truncatula: TN6.18 and Jemalong. Calcareous soil significantly restricted shoot growth only in Jemalong (-45 % of the control). When grown on calcareous soil, root length was stimulated, this effect being more pronounced in TN6.18. Under calcareous soil, net CO2 assimilation declined more in Jemalong (-40 % of the control) than in TN6.18 (-20 % of the control). CO2 accumulation was increased in Jemalong (+35% of the control) plants grown in calcareous soil. The acid phosphatase activity was higher in plants cultivated under calcareous soil. This increased phosphatase activity was more pronounced in TN6.18, which showed higher accumulation of Pi in shoots and roots than Jemalolng. In the light of these results, the present study proposes acid phosphatase as a useful candidate for improving Pi acquisition and utilization under calcareous soil.

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.

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. [ABSTRACT FROM AUTHOR]

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Phosphorus (P) is the most deficient nutrient in agricultural soils after nitrogen. Additionally, exogenously applied P quickly transforms into less soluble compounds through various chemo-sorption reactions resulting in poor fertilizer use efficiency (15–25%). Therefore, this pot experiment was conducted to investigate the impact of foliar P (0, 45, 90 and 135 mM KH2PO4) in conjunction with soil applied P (0, 10 and 20 mg P kg−1) for enhanced growth and P use efficiency of maize and wheat in calcareous soils. There was a linear increase in plant height and biomass both with the increasing application of soil and foliar P in both wheat and maize crop. However, the effect of foliar P was more pronounced in P deficient condition compared to 10 or 20 mg P kg−1. Soil applied P at 10 and 20 mg P kg−1 increased plant dry biomass by 10.8 and 16.8% in maize and by 29.9 and 35.5% in wheat over control, respectively. Foliar P application didn't improve soil phosphorus. The interaction between soil and foliar P was significant (p ≤.05) showing that increase of either foliar or soil P application, tissue P content of both maize and wheat increased. In both season the higher foliar P solution resulted in higher P uptake though the increase in wheat were lower than maize. Therefore, the low recovery of soil P associated with poor soil characteristics could be corrected through its foliar application if administered at proper growth stage with suitable concentration strength and appropriate source. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is the most important non-renewable fertilizer determining agricultural production and productivity of any crop. Wheat is one of the prime cereals consumed worldwide providing calories, vegetable protein and dietary fibre to the growing population. Wheat cultivation consumes nearly 40% of the P used by cereal crops annually which is higher than any other cereal crop. Unlike other nutrients, P gets complexed and fixed in the soil and only a small proportion of the P applied as fertilizer is available to the crop; additionally, loss of P through seepage of water into the water bodies causes eutrophication. An economical, environmentally-friendly and sustainable solution would be to identify QTL(s)/gene(s) responsible for efficient P uptake and use. OsPstol1 in rice was reported to enhance early root growth thus causing an improved P uptake and eventually increased yield. In this investigation we attempted to explore the genetic diversity of the wheat ortholog of OsPstol1 in a diverse panel of germplasm. On re-sequencing we found the putative wheat ortholog TaPstol5AS-1, to be highly conserved in 33 wheat germplasm, and speculate it to have undergone high selection pressure. Additionally, we also hypothesize that Pstol in wheat could be a group of homo(eo)log, regulating the P homoeostasis in wheat like SbPSTOL1 (Sorghum) and ZmPSTOL1 (Maize). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

• Phosphorus input and output circularity of food systems of 125 countries estimated. • Prospects and mechanisms for increasing phosphorus circularity discussed. • Output circularity was lower in importing countries than in exporting countries. • Input circularity was higher in importing countries than in exporting countries. • Unrecycled residues, manures and wastes were main P losses from food systems. • Global need for targeted policy incentives to increase recycling in food systems. International trade of food and feed is increasing, which may limit nutrient recycling in food systems, to an unknown extent. We examined phosphorus (P) circularity in food systems of 88 main importing countries and 37 main exporting countries for 2000–2018. We inferred P input circularity (P in recycled residues as share of total P inputs), and P output circularity (P in recycled residues as share of total P in residues). Global mean output circularity was 65%, and slightly higher for exporting countries than importing countries. Global mean input circularity for cropland was 77% in importing countries and 62% in exporting countries, suggesting that residues from imported products contributed to P circularity. Our study provide insights in the prospects and mechanisms for increasing P circularity, which may help policy makers to design targeted interventions that minimize the need for synthetic P fertilizer and lower P losses in food systems. [Display omitted] [ABSTRACT FROM AUTHOR]

Overuse of phosphorus (P) fertilizer in maize production in China is causing severe environmental pollution and cropping issues, requiring an integrative P fertilizer strategy that improves P use efficiency (PUE) and sustainable production. This meta-analysis on P fertilizer use for maize cropping in China used 786 paired observations to quantify the effects of P fertilizer management (P fertilizer variety, P application rate, application method) and different soil properties (pH, available P, organic matter) on grain yield, PUE, and the environmental cost. The mean maize grain yield of 8.86 t ha 1 with a PUE of 97.2 kg kg 1 and an environmental cost of 1.51 $ kg 1. There was a linear plus plateau relationship between yield and P application rate under different soil available P and growing regions. No significant differences in yield increase occurred between P fertilizer type or P application rate, except for triple superphosphate and P application rate > 26 kg P ha 1. Significant yield increases with P fertilizer application occurred on soil with pH< 7, 10–20 mg kg-1 soil available P, or > 30 g kg-1 organic matter content. Adopting optimized P fertilizer management in different regions not only enhanced maize yield by 23.3 % and PUE by 39.2 %, but also effectively reduced the P application rate by 12.4–34.1 % and the environmental cost by 24.3 %. Consequently, prioritizing suitable P fertilizer recommendation strategy will significantly benefit the pursuit of sustainable maize production in China and similar regions. [Display omitted] • Maize yield increased with P application rate in a linear plus plateau way. • Soil pH, Olsen-P and organic matter had impacts on yield increases by P application. • Average partial productivity of P fertilizer (PFPP) in China's maize was 97.2 kg kg 1. • For each 10 kg ha-1 increase in P fertilizer, the environmental cost increased by 0.24 $ kg 1. • Rational P strategy increased yield and PUE, and reduced environmental cost. [ABSTRACT FROM AUTHOR]

Phosphorus (P) imbalances in agricultural systems are a global problem because they have environmental and economic impacts, like eutrophication when there is a soil P surplus and low crop productivity in P deficient soils. Fertilisers are used to increase soil available P, but some fractions become less available P forms and reduce P use efficiency (PUE). Legacy P includes labile and moderately labile P fractions that could replenish soil available P and become available for crops under long-term P fertilisation and affects PUE. Our aim was to evaluate the long-term legacy P dynamic and PUE with different P fertilisation strategies and rates in soils of Entre Ríos, Argentina. Long-term experiments in two contrasting soil types (Mollisol and Vertisol), were used to evaluate a combination of three initial (0, 100, and 200 kg P ha−1) and four annual P fertilisation rates (0, 12, 24, and 36 kg P ha−1 year−1). Soil samples were collected annually at 0–5 cm, 5–10 cm, and 10–20 cm soil depth. Bray1-P concentration was used as an index of soil available P. Grain P concentration and crops grain yield were measured. The effects of the initial P fertilisation on Bray1-P were observed for a longer time in the Mollisol than the Vertisol, which may be related to a lower P adsorption capacity of the Mollisol. Annual P fertilisation increased Bray1-P earlier in deep layers in the Vertisol, associated with the preferential flow of P fertiliser through soil cracks in the latter. After 10 years, Bray1-P stratification was higher in the Vertisol than in the Mollisol. In the treatment without initial P fertilisation (i.e., 0 kg P ha−1), the annual fertilisation rate to maintain Bray 1-P level was similar on both soils (on average 24 kg P ha−1). Our results showed that the annual P fertilisation strategy to feed crops' needs produces higher PUE compared with the use of residual legacy P after an initial and unique high P fertilisation rate. This information is relevant to design highly efficient P fertilisation strategies according to soil characteristics, thereby advancing the pursuit of sustainability in agricultural systems. • Legacy P and PUE with different P fertilisation strategies and rates were assessed. • After 10 yr, the initial P fertilisation affected Bray1-P only in the Mollisol. • The relationship between apparent P balances and Bray1-P differed between sites. • Higher long-term P use efficiency was achieved with annual P fertilisation. [ABSTRACT FROM AUTHOR]

Nutrient distribution and phosphate fertilizers can impact maize growth, but how to match the type of phosphate fertilizer and the application method to enhance root-foraging capacity for phosphorus (P) is unclear. This study was aimed at characterizing the effects of different phosphate fertilizers and placements on maize growth, grain yield, root properties and rhizosphere processes on calcareous soil. A soil column experiment with five different phosphate fertilizers [single superphosphate (SSP), monoammonium phosphate (MAP), diammonium phosphate (DAP), urea phosphate (UP) and ammonium polyphosphate (APP)] applied either uniformly or locally 10–20 cm deep in a greenhouse. In addition, a 2-year field experiment with five P fertilizer treatments (non-fertilization and broadcast MAP, DAP, UP or APP) was conducted. In the soil column experiment, localized application of SSP, MAP, UP and APP significantly promoted the growth and P uptake of maize by modifying the root morphology. Localized application of each P fertilizer increased (by up to 74 %) the first-order lateral root density and first-order lateral root length of maize in the fertilizer-enriched layer, resulting in a significant increase in the efficiency of root P acquisition by maize. In the field experiment, the rhizosphere pH of maize supplied with MAP, UP or APP was reduced by 0.5–0.7 units in comparison to DAP in 2018. Compared with MAP and DAP, application of UP or APP in the field did not show significantly improve maize growth and P uptake. These results show that optimizing P fertilizer types and placement modified root morphology and physiology, and consequently promoted maize growth and P accumulation, but further characterization of the localized application of different P fertilizers in the field is needed. Engineering root properties and rhizosphere processes by manipulating fertilizer types and placement improves fertilizer-use efficiency and reduces environmental footprint of food production. • Localized application of SSP, MAP, UP or APP (but no DAP) promoted maize growth. • In P fertilizer patches, the maize 1st lateral root length and density increased. • Localized application of SSP, MAP, UP or APP improved root efficiency for P uptake. • MAP, UP and APP have the potential of decreasing pH in the maize rhizosphere soil. • Root and rhizosphere management improves fertilizer-use efficiency for maize. [ABSTRACT FROM AUTHOR]

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.

Inorganic phosphate (Pi) is an essential macronutrient required for many fundamental processes in plants, including photosynthesis and respiration, as well as nucleic acid, protein, and membrane phospholipid synthesis. The huge use of Pi-containing fertilizers in agriculture demonstrates that the soluble Pi levels of most soils are suboptimal for crop growth. This review explores recent advances concerning the understanding of adaptive metabolic processes that plants have evolved to alleviate the negative impact of nutritional Pi deficiency. Plant Pi starvation responses arise from complex signaling pathways that integrate altered gene expression with post-transcriptional and post-translational mechanisms. The resultant remodeling of the transcriptome, proteome, and metabolome enhances the efficiency of root Pi acquisition from the soil, as well as the use of assimilated Pi throughout the plant. We emphasize how the up-regulation of high-affinity Pi transporters and intra- and extracellular Pi scavenging and recycling enzymes, organic acid anion efflux, membrane remodeling, and the remarkable flexibility of plant metabolism and bioenergetics contribute to the survival of Pi-deficient plants. This research field is enabling the development of a broad range of innovative and promising strategies for engineering phosphorus-efficient crops. Such cultivars are urgently needed to reduce inputs of unsustainable and non-renewable Pi fertilizers for maximum agronomic benefit and long-term global food security and ecosystem preservation. [ABSTRACT FROM AUTHOR]

Maize (Zea mays L.) is an important crop worldwide, but in many regions is increasingly faced with the issue of phosphorus (P)-deficient soils. The aim of this study was to screen for low P-tolerance in maize and to dissect the underlying phenotypic response. To this end, we evaluated a panel of 380 diverse inbred lines in the field under low and normal P conditions for 17 morphological, biomass- and yield-related traits. All traits showed a significant genotypic variation and a moderate to high repeatability for each P condition. Under P deficiency, all traits were significantly lower compared to the control with normal P availability. The variance due to the interaction between genotype and P condition was significant for most traits, but generally small compared to the genotypic variance. Regarding the low P tolerance index, i.e. the phenotype under low P relative to the control, we observed a generally similar response within the morphological, biomass- or yield-related traits. Interestingly, genotypes showing little yield reduction under low P appear to achieve this tolerance through different strategies. Based on our results, low-P tolerant and low-P sensitive lines were identified, which can be used for further genetic research as well as to improve this globally important trait in maize breeding. [ABSTRACT FROM AUTHOR]

Biochar amendments offer promising potential to improve soil fertility, soil organic carbon (SOC) and crop yields; however, a limited research has explored these benefits of biochar in the arid and semi‐arid regions. This two‐year field study investigated the effects of Acacia tree biomass‐derived biochar, applied at 0 and 10 t ha‒1 rates with farmyard manure (FYM) or poultry manure (PM) and mineral phosphorus (P) fertilizer combinations (100 kg P ha‐1), on maize (Zea mays L.) productivity, P use efficiency (PUE) and farm profitability. The application of biochar with organic–inorganic P fertilizers significantly increased soil P and SOC contents than the sole organic or inorganic P fertilizers. Addition of biochar and PM as 100% P source resulted in the highest soil P (104% increase over control) and SOC contents (203% higher than control). However, maize productivity and PUE were significantly higher under balanced P fertilizer (50% organic + 50% mineral fertilizer) with biochar and the increase was 110%, 94% and 170% than 100%‐FYM, 100%‐PM and 100% mineral fertilizer, respectively. Maize productivity and yield correlated significantly positively with soil P and SOC contents These positive effects were possibly due to the ability of biochar to improve soil properties, P availability from organic–inorganic fertilizers and SOC which resulted in higher PUE and maize productivity. Despite the significant positive relationship of PUE with net economic returns, biochar incorporation with PM and mineral fertilizer combination was economically profitable, whereas FYM along biochar was not profitable due to short duration of the field experiments. [ABSTRACT FROM AUTHOR]

The Mediterranean agricultural sector faces many challenges related to water and mineral resource use for crop production and food security for an exponentially growing population. Phosphorus drip fertigation has recently emerged as an efficient and sustainable technique to improve water and nutrient use efficiency under such challenging pedoclimatic conditions. The classical methods for administering standard P fertilizers to crops (broadcasting and banding) have shown their limitations in terms of P acquisition and use efficiency. More than 60 % of applied P through dry P fertilizers is rapidly transformed into recalcitrant P forms and subsequently lost by soil erosion increasing the effects of P eutrophication issues on the ecosystem's sustainability. The emergence of new advanced irrigation technologies like high-frequent drip irrigation must be accompanied by the development of new P formulations with high water solubility and greater P use efficiency. This review illustrates the state of the art for P fertilizers used in Mediterranean agriculture in the last decades. An overall description is provided for the P fertilizer formulas, their physicochemical properties, as well as their suitability for drip fertigation systems and the consequent effects of their application on photosynthesis, plant growth, and crop productivity. The key factors influencing P fertilizer transformations and use efficiency under drip fertigation systems are extensively discussed in this review with a focus on the differences between orthophosphate and polyphosphate formulations., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Phosphorus (P) is the second most important nutrient after nitrogen (N) required to plants for optimum growth and development. For alkaline and calcareous soils, the phosphorus use efficiency ranges from 10 to 25%, as major portion of phosphatic fertilizers becomes precipitated in soil and results in decreased crop yield. Rock phosphate (RP) as P source particularly in compost form has captivated the attention being cost effective P-fertilizer. However, the solubility of RP is a major concern. The bio-augmentation and bio-stimulation i.e. addition of phosphate solubilizing bacteria (PSB) and provision of limiting nutrients (molasses and urea), along with the organic manures can alleviate the problem of the rock phosphate solubilization by producing organic and mineral acids, deceasing soil pH, releasing anions and covering soil aggregates surfaces. Hence, bio-activated rock-phosphate (B-RP) was prepared through composting process by using poultry and animal manures along with RP, bio-augmented with consortium of PSB i.e. group of three strains of bacteria including Bacillus (MN-54), Enterobacter (MN-17) and Pseudomonas (E-11) and bio-stimulated with molasses (5 %) and urea (10 %). Thereafter this bio-activated rock phosphate was used alone and in different combinations with di-ammonium phosphate (DAP) during field experiment. Treatment B-RP + DAP in equal proportion improved biological yield by 19.81 %. It also resulted in 34.19, 71.24 and 29.42 % increase in N, P, K contents of grains, respectively and 40.09, 64.90 and 25.21 % increase in N, P, K contents of straw, respectively as compared to sole application of DAP as P-source i.e. DAP (100 % P). It had also improved total P-uptake (100.71 %) and recovery efficiency of P (121.86 %) of wheat as compared to that of DAP (100 % P). Moreover, the leading treatment also improved 21% grain yield over sole application of DAP. So, It is concluded that integrated use of B-RP and DAP with equal proportion of recommended P may serve as a better management practice for improving quantity of grain produced. [ABSTRACT FROM AUTHOR]

Abstract 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.

Low phosphorus availability in cultivated soils limits sustainable crop production in sub‐Saharan Africa. This study aimed at evaluating the effect of long‐term application of different types of organic amendments on soil P forms, P use efficiency and sorghum yields. A long term experiment established in 1980 at Saria in Burkina Faso, comparing the effects of manure, compost and sorghum straw was used. Manure and compost significantly increased organic P and resin‐P by about 35% and 64%, respectively after 10 and 32 years of sorghum cultivation, and HCl‐P after 32 years of cultivation compared to the control. Manure significantly increased NaHCO3-Pi and NaOH-Pi by 63% and 26%, respectively compared to the control. Sorghum straw had little effect on measured soil P forms. Manure and compost were the best in increasing sorghum grain yield, which effect were strongly correlated to soil pH, carbon and nitrogen. The partial factors productivities of P resulting from the application of studied organic amendments were similar and low, but significantly higher than that of the control treatment. Organic amendments with high P content, maintaining soil carbon and pH could be used to improve soil P availability, sorghum yield and reduce the demand for mineral phosphorus fertilizers.

Abstract 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.

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.

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.

A large portion of applied phosphorus fertilizer undergoes adsorption/fixation due to high pH and calcareous content of soils and becomes unavailable for plant uptake. Plants undergo many morphological and physiological adaptations to overcome the low phosphorus availability. Many plants modify their root morphology and biomass in low phosphorus environments by exploring a greater more soil volume. This study measured plant root morphological and biomass adaptation at different levels of applied phosphorus and its effect on phosphorus use efficiency. Results showed that phosphorus use efficiency, root volume, number of root tips, root surface area, root length, and root length were higher at a low levels of phosphorus with average root diameter and root phosphorus were reduced at lower levels of applied phosphorus. Maize performed better in case of root adaptation; however, phosphorus use efficiency was higher for wheat. Both plant species responded to low phosphorus application by enhancing their root morphology and root production with an increase in phosphorus use efficiency. A significant correlation (r2 ≥ 60%) was observed between root morphology and phosphorus use efficiency. Plants that explore more soil volume by modifying root morphology were found to have low critical phosphorus requirements by efficiently utilizing phosphorus and amount of phosphorus fertilizer application is reduced. [ABSTRACT FROM AUTHOR]

This study aims to explore the effects of inoculating arbuscular mycorrhizae fungi (AMF) and phosphate solubilizing bacteria (PSB) on the dry matter yield of alfalfa, and phosphorus use efficiency under various treatments with different phosphorus level, and thereby an optimal fertilization mode was established for the selected alfalfa. A randomized block design was used in the experiment for two factors of bacteria and phosphorus. Four levels of phosphorus application were set, including 0 (P0), 50 (P1), 100 (P2), and 150 mg/kg (P3). Four types of inoculation treatments were as follows: no inoculation (J0), Funneliformis mosseae (J1), Bacillus megaterium (J2), and double inoculation (B. megaterium + F. mosseae) (J3). Sixteen treatments were set, each of which was repeated six times. The treatment group was inoculated with Funneliformis mosseae, where the average amount of fungus was 10 g/pot. In the treatment group of Bacillus megaterium, the average amount of bacterial solution was 10 mL/pot. In the mixed inoculation group, Bacillus megaterium in each pot was added the amount of 5 g (about 8 500 inoculation potential units) and 5 mL. The same number of sterilized bacteria was also added to the J0 treatment. The results showed that the dry matter yield of alfalfa at the total or individual cut gradually increased first and then decreased, with the increase in the application rate of phosphorus under the same conditions of bacteria treatment. In the J3 treatment, the total dry matter yield of alfalfa reached the maximum under the P1 phosphorus level. In the rest of bacteria application conditions, the total dry matter yield of alfalfa reached the maximum in P2 phosphorus level. The phosphorus content of aboveground plants increased first and then decreased, as the application rate of phosphorus increased. Specifically, the content of phosphorus in treatment group was significantly higher than that in the non-phosphorus treatment (P<0.05), whereas, there was no significant difference between phosphorus application treatments (P>0.05). The partial productivity and agronomic efficiency of phosphorus fertilizer decreased, with the increase of phosphorus application rate. The contents of total phosphorus (TP) and rapid available phosphorus (AP) increased in rhizosphere soil and non-rhizosphere soil, with the increase in the application rate of phosphorus. In the same phosphorus conditions, the dry matter yield, phosphorus content of plant, use efficiency of phosphorus, TP, and AP content of alfalfa under the single or mixed inoculation treatments were significantly higher than those under non-inoculation treatment (P<0.05), where the contents of TP and AP reached the maximum in the J3 treatment. There was the highest correlation coefficient between the AP content in rhizosphere soil and dry matter yield, indicating the optimal fitting effect. The contents of TP and AP were positively correlated with the total dry matter yield. Therefore, when the application rate of phosphorus was set as 100 mg/kg, the comprehensive inoculation of AMF and PSB can significantly increase the phosphorus availability in soil, thereby to improve phosphorus use efficiency, further to increase the dry matter yield of alfalfa. The finding can provide a theoretical basis for the high production of alfalfa, and the application of efficient compound microbial fertilizer. [ABSTRACT FROM AUTHOR]

Anaerobic digester development on dairy, poultry, and swine confined animal feeding operations (CAFOs) reduce manure storage, produce energy and are poised to supply a variety of nutrient-rich materials. Field experiments were conducted in the Columbia Basin of South-Central Washington to evaluate the yield response and phosphorous (P) use efficiency of sweet corn (Zea mayes convar. saccharata cv. Sheba) to the application of P from anaerobic-digested manures. Treatments consisted of the application of 0, 10, 20, 40 kg P ha−1 from five sources, three from anaerobic digesters (AD); AD-dairy P fine solids; AD centrifuged poultry solids; and AD dairy-derived struvite-P compared to a commercial poultry fertilizer, commercial mono-ammonium phosphate, and a non-amended control. Sweet corn yields were not significantly different among P amendments or rates of application but were different between years and were greater than the No-P treatment in 2014. Phosphorus recovery efficiency defined as that percentage of applied P recovered by sweet corn averaged 138% among treatments receiving 10 kg P ha−1 and declined to 57% for higher rates of poultry materials and the commercial mono-ammonium phosphate (MAP) in 2013 and declined 50% in 2014 due to lower yields. Although yield was not different the uptake of P among treatments was significantly greater than the unfertilized control. The lack of yield differences among rates of P applied indicates that P was not limiting yield and suggests that under these production conditions the application of 10 kg P ha−1 of any of the amendments was sufficient. Abbreviations: AD: anaerobic digestion; ADD: anaerobic-digested dairy manure; ADP: anaerobic digested poultry manure; ADS: anaerobic-digested struvite; DM – dry matter; MAP – mono ammonium phosphate; PBP a commercial poultry fertilizer; PRD: percent P recovery efficiency difference method; PRB: percent P recovery balance method; PUE: Phosphorus use efficiency; AUE – Agronomic utilization efficiency. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Under low phosphorus (P) availability, plants change their root physiology and release more protons and carboxylates to acquire P from residual sources. This ability differs among genotypes. In this situation, P efficient genotypes may be a conceivable way of decreasing the P demand and using applied P efficiently. This study was planned with the objective of screening P efficient wheat and maize genotypes on the basis of carboxylate and proton release under P deficient condition. Five genotypes each of wheat and maize were grown in solution culture with normal and deficient P treatments under CRD (completely randomized design) factorial. At harvest carboxylates, proton and P were analyzed. Results revealed that wheat genotype, SARC-1 and maize genotype, Pioneer-32F10 was better in carboxylate exudation and more release of carboxylates and proton was recorded in these genotypes comparative to other genotypes. Both genotypes also showed better P and phosphorus use efficiency in P deficient treatment compared to normal P treatment. In the case of species, maize roots released more fraction of malate and wheat roots released more fraction of citrate. This genetic difference can be used for the selection of P efficient genotypes for P deficient soils through the breeding process in the future. [ABSTRACT FROM AUTHOR]