Search

Lichens contain a sufficient amount of plant nutrients for plant growth. Studies have shown that the characteristic secondary metabolites they produce contain significant amounts of organic acids, amino acids, and hormones. This study aims to examine the effects of 10 different lichen species Aspicilia calcarea (A. calcarea), Cetraria islandica (C. islandica), Cladonia furcate (C. furcate), Flavoparmelia caperata (F. caperata), Lobaria pulmonaria (L. pulmonaria), Pseudevernia furfuracea (P. furfuracea), Rhizoplaca chrsoleuca (R. chrsoleuca), Umbilicaria vellea (U. vellaa), Xanthoparmelia somloensis (X. somloensis), Usnea longissima (U. longissima) on metabolic properties and growth parameters of maize plant for possible use as a plant food source in sustainable and organic agriculture. As a result of the research, it was observed that when lichen species were applied as plant nutrients, there were significant increases in plant height, plant weight, dry matter ratio, some nutrient content and amino acid levels of maize compared to the control group. Among the treatments, Lobaria pulmonaria application at 5 g/kg resulted in the highest values for plant height (145.00 cm), plant weight (187.00 g), and dry matter ratio (19.21%). The research shows that different lichen species significantly affect the amino acid content, nutrient content, and growth parameters of the maize plant at various levels. [ABSTRACT FROM AUTHOR]

Soil nutrient cycling in forest ecosystems is a dynamic process fundamentally influenced by climatic and environmental factors. This review synthesizes studies focusing on nutrient dynamics in forests of Pinus and Eucalyptus species, highlighting the sensitivity of these systems to current climatic extremes. We emphasize that most research has been conducted predominantly in natural forests and plantations of Pinus (77%), with an increasing trend of studies on Pinus in natural environments and Eucalyptus in planted forests. Noteworthy, soil sampling in these studies has been primarily concentrated on the upper 30 cm of soil, where nutrient interactions are most pronounced. The relationship between litter and plant organ nutrients as well as soil fertility has been a significant focus of these studies, along with the role of nitrogen and carbon in response to global change. Also, we noticed the importance of research on water availability in the broader context of nutrient cycling. Our review underscores the necessity for continued research in this field, particularly to support informed management and adaptation strategies for both plantations and natural forests in the face of environmental change.

Aims: The current study is designed to determine the chlorophyll a, to calculate the primary biological productivity of oxygen and carbon and plant nutrient (phosphate, silica, nitrite and nitrate) monthly in the groundwater of six wells in the Alshirqat area from October 2021 to March 2022. Groundwater is an essential source of water in Salaheddin province, Iraq. Methodology and results: Water is pumped out by electrical pumps. Samples were taken monthly early in the morning after pumping out water for 10 min from October 2021 to March 2022 with clean polyethylene bottles after washing with the same water several times, depending on sample test requirements. Water and air temperatures were measured at the time of sample taking. The tests were quickly conducted in the College of Sciences, Tikrit University Laboratory. The results clarify the monthly variation of the above properties. Air and water temperature ranged from 3-30 °C and 16-25 °C, respectively. The plant nutrients (phosphate, silica, nitrite and nitrate) values were 2.51-3.489 mg/L, 0.397-6.913 mg/L, 0.277-0.697 µg/L and 5.3-8.7 mg/L, respectively. The range of the chlorophyll a in the groundwater samples, the primary oxygen productivity and primary carbon productivity varied between 0.534-74.844 mg/L, 9.43-19.12 mg/L and 353.8-716.9 µg/m3/day, respectively. Conclusion, significance and impact of study: The groundwater in the west of Alshirqat, Salaheddin, Iraq rich in plant nutrients (silica, phosphate, nitrite and nitrate) and chlorophyll, with high primary oxygen and carbon productivity. [ABSTRACT FROM AUTHOR]

Jatropha curcas is an oil producing seed with high nutritional qualities for consumption. However, due to inherent anti-nutritional factors, appropriate processing is necessary to improve its nutrients utilization. This study was aimed at processing J. curcas using solvent-extraction method and evaluating its inclusion effects in the diet for Clarias gariepinus on its growth status. J. curcas meal was extracted using 80 % methanol to remove phorbol esters and other anti-nutrients. Thereafter, five iso-nitrogenous diets (40 % crude protein) were formulated containing J. curcas meal replacements of soybeans meal at 0 % (TRT0), 25 % (TRT25), 50 % (TRT50), 75 % (TRT75) and 100 % (TRT100) and fed to C. gariepinus for 70 days. Results showed that TRT25 fish had the highest mean weight gain and specific growth. The serum alkaline phosphate, alanine aminotransferase, and aspartate aminotransferase levels began to rise significantly (p ≤ 0.05) at 50 % replacement. Likewise, the assessment of gut ecology and morphology indicated that TRT25 had significantly (p ≤ 0.05) the highest gut bacteria colony forming unit (2.60 ×104±0.02cfu/g) and most favorable area of absorption (0.16±0.01 cm2). The histopathological observation of the fish intestine, liver and gills indicated no visible deformity in TRT0 and TRT25 fish. However, various degrees of degenerations were observed in the fish fed with 50 % and higher inclusion of J. curcas. This study showed that methanol-extracted J. curcas meal can be effectively utilized for C. gariepinus at 25 % of replacement.

Abstract Background Grazing exclusion is an efficient practice to restore degraded grassland ecosystems by eliminating external disturbances and improving ecosystems’ self-healing capacities, which affects the ecological processes of soil-plant systems. Grassland degradation levels play a critical role in regulating these ecological processes. However, the effects of vegetation and soil states at different degradation stages on grassland ecosystem restoration are not fully understood. To better understand this, desert steppe at three levels of degradation (light, moderate, and heavy degradation) was fenced for 6 years in Inner Mongolia, China. Community characteristics were investigated, and nutrient concentrations of the soil (0–10 cm depth) and dominant plants were measured. Results We found that grazing exclusion increased shoots’ carbon (C) concentrations, C/N, and C/P, but significantly decreased shoots’ nitrogen (N) and phosphorus (P) concentrations for Stipa breviflora and Cleistogenes songorica. Interestingly, there were no significant differences in nutrient concentrations of these two species among the three degraded desert steppes after grazing exclusion. After grazing exclusion, annual accumulation rates of aboveground C, N, and P pools in the heavily degraded area were the highest, but the aboveground nutrient pools were the lowest among the three degraded grasslands. Similarly, the annual recovery rates of community height, cover, and aboveground biomass in the heavily degraded desert steppe were the highest among the three degraded steppes after grazing exclusion. These results indicate that grazing exclusion is more effective for vegetation restoration in the heavily degraded desert steppe. The soil total carbon, total nitrogen, total phosphorus, available nitrogen, and available phosphorus concentrations in the moderately and heavily degraded desert steppes were significantly decreased after six years of grazing exclusion, whereas these were no changes in the lightly degraded desert steppe. Structural equation model analysis showed that the grassland degradation level mainly altered the community aboveground biomass and aboveground nutrient pool, driving the decrease in soil nutrient concentrations and accelerating nutrient transfer from soil to plant community, especially in the heavily degraded grassland. Conclusions Our study emphasizes the importance of grassland degradation level in ecosystem restoration and provides theoretical guidance for scientific formulation of containment policies.

Soil analysis is a crucial component of agricultural production, as it provides information about the nutrient content in soil to recommend fertilizer guidelines and make informed decisions to optimize crop yields and promote sustainable agriculture. Near-infrared (NIR) reflectance spectroscopy holds great promise as an analytical tool with several advantages, such as rapid, nondestructive, and without the need for chemicals, making it a promising alternative to traditional laboratory methods to determine nutrient contents in soil. This study used two multivariate techniques partial least square regression (PLSR) and locally weighted PLSR (LWPLSR) to construct calibration models to relate NIR spectra to the total nitrogen (total N), available phosphorus (available P), extractable potassium (extractable K) and extractable ammonium (NH4+) contents in soil samples. The results showed that the LWPLSR model outperformed the PLSR model. The best predictions were obtained using LWPLSR model for total N (R2 = 0.87 and RMSEP = 0.133), available P (R2 = 0.68 and RMSEP = 9.013), extractable K (R2 = 0.84 and RMSEP = 15.436) and extractable NH4+ (R2 = 0.73 and RMSEP = 6.789). This work demonstrated the potential of LWPLSR coupled with NIR spectroscopy for efficient soil analysis, providing the geographical neighbors of the test sample present in the calibration database. [ABSTRACT FROM AUTHOR]

Background: Grazing exclusion is an efficient practice to restore degraded grassland ecosystems by eliminating external disturbances and improving ecosystems' self-healing capacities, which affects the ecological processes of soil-plant systems. Grassland degradation levels play a critical role in regulating these ecological processes. However, the effects of vegetation and soil states at different degradation stages on grassland ecosystem restoration are not fully understood. To better understand this, desert steppe at three levels of degradation (light, moderate, and heavy degradation) was fenced for 6 years in Inner Mongolia, China. Community characteristics were investigated, and nutrient concentrations of the soil (0–10 cm depth) and dominant plants were measured. Results: We found that grazing exclusion increased shoots' carbon (C) concentrations, C/N, and C/P, but significantly decreased shoots' nitrogen (N) and phosphorus (P) concentrations for Stipa breviflora and Cleistogenes songorica. Interestingly, there were no significant differences in nutrient concentrations of these two species among the three degraded desert steppes after grazing exclusion. After grazing exclusion, annual accumulation rates of aboveground C, N, and P pools in the heavily degraded area were the highest, but the aboveground nutrient pools were the lowest among the three degraded grasslands. Similarly, the annual recovery rates of community height, cover, and aboveground biomass in the heavily degraded desert steppe were the highest among the three degraded steppes after grazing exclusion. These results indicate that grazing exclusion is more effective for vegetation restoration in the heavily degraded desert steppe. The soil total carbon, total nitrogen, total phosphorus, available nitrogen, and available phosphorus concentrations in the moderately and heavily degraded desert steppes were significantly decreased after six years of grazing exclusion, whereas these were no changes in the lightly degraded desert steppe. Structural equation model analysis showed that the grassland degradation level mainly altered the community aboveground biomass and aboveground nutrient pool, driving the decrease in soil nutrient concentrations and accelerating nutrient transfer from soil to plant community, especially in the heavily degraded grassland. Conclusions: Our study emphasizes the importance of grassland degradation level in ecosystem restoration and provides theoretical guidance for scientific formulation of containment policies. [ABSTRACT FROM AUTHOR]

Fish waste and Tithonia diversifolia are the essential ingredients of organic fertilizer. Several researchers have already tested these two materials, which have high plant nutrient content. This study aims to determine the effect of liquid organic fertilizer from marine fish waste and tithonia application on shallot (Allium ascalanicum L.) production. The research was conducted in Kuranji Subdistrict, Kuranji District, Padang City, West Sumatra, Indonesia, at 15 meters above sea level from November 2022 to March 2023. The experiment used a completely randomized design (CRD) with six treatments and four replications, resulting in 24 experimental units. The data were analyzed using analysis of variance (ANOVA) with a significance level of 5%. If there was a significant effect, Duncan's New Multiple Range Test was conducted at a significance level of 5%. The treatments consisted of 0, 10, 20, 30, 40, and 50 ml/L. The application of liquid organic fertilizer from marine fish waste and tithonia at 40ml/L is the most effective for shallot production, yielding the highest production per hectare at 12.13 tons/ha

Background: Encrusted seeds receive a thinner coating than encrusted seeds and the coating process is halted before full roundness is achieved. This is beneficial for soybean seeds and enhances water-use efficiency during germination. Additionally, adding essential nutrients to seeds promotes germination and growth, enabling soybean plants to grow faster and to have a higher yield. Methods: Soybean seeds were encrusted with 3.45 g/kg NH4NO3, 4.60 g/kg NaH2PO4.H2O and 1.87 g/kg KCl, using vermiculite as the encrusting material and 0.4% w/w aqueous-carboxymethyl cellulose as the binder. The encrusting process was carried out in a rotary drum (Model SKK12) spinning at 40 rpm and the seeds were evaluated for seed quality parameters. Result: Encrusting seeds with all three types of plant nutrients had a positive impact on enhancing seed quality compared to nonencrusted seeds. In particular, encrusting seeds with 50 g/kg vermiculite and 1.87 g/kg KCl did not hinder the germination process. Moreover, it enhanced both the germination rate and speed of germination. Additionally, it promoted plant growth, including fresh and dry root weight, fresh shoot weight, fresh and dry plant weight, number of pods per plant, number of seeds per plant, seed weight per plant and pod weight per plant. Therefore, encrusting seeds with 50 g/kg vermiculite and 1.87 g/kg KCl is recommended to enhance the quality of Chiang Mai 60 soybean seeds. [ABSTRACT FROM AUTHOR]

Jujubes (Ziziphus jujuba) are a crucial industry in the arid region of Xinjiang, facing challenges such as water scarcity and low water use efficiency. This study focuses on jujube orchards located at the edge of the Taklimakan Desert to investigate whether applying trace elements can effectively enhance jujube growth, development, and fruit quality. By foliar spraying boron and zinc micro-fertilizers onto jujube leaves, we analyzed the effects of different doses on growth parameters, photosynthetic activity, crop yield, water use efficiency, and fruit quality. The results revealed that the length of the fruit branch, leaf area index, and fruit longitudinal/transverse diameter increased by 19.35%, 25.72%, and 32.9%/2.28%, respectively; net photosynthetic rate, transpiration rate, and stomatal conductance increased by 105.51%, 91.43%, and 75.3%, respectively, while intercellular CO2 concentration decreased by 13.09%; yield and water use efficiency improved by 16.95% and 12.68%, respectively; soluble sugar content, titratable acid content, and flavonoid content increased by 13.56%, 51.63%, and 86.12%, respectively. Based on these findings, the optimal application rate for boron micro-fertilizer was determined to be 3.51~3.59 kg/hm2, and for zinc micro-fertilizer, it was 3.16~3.32 kg/hm2. This study provides practical methods along with theoretical support for applying micro-fertilizers in arid regions. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, in order to determine the effects of biochar applications on the physical and chemical properties of soils grown in Kayra bread wheat variety, this study was carried out in the form of a pot experiment in a randomized plot design with three replications and at five different doses 0 (B0), 10 (B1), 20 (B2), 40 (B3) and 80 (B4) t ha-1 biochar were applied. According to biochar applications, the highest pH, EC, lime, organic matter, total N, available P, K, Ca, Mg, Na, Zn, Fe, Mn, Cu and B values in the soil are 7.66, 2.26 mS cm-1, 3.55%, 2.81%, 0.201%, 48.89 mg kg-1, 1172.89 mg kg-1, 2268.88 mg kg-1, 186.92 mg kg-1, 101.43 mg kg-1, 2.34 mg kg-1, 2.40 mg kg-1, 7.33 mg kg-1, 1.79 mg kg-1 and 1.08 mg kg-1respectivelythe highest values were determined in B4 (80 t ha-1) application. The lowest values in soil according to biochar applications were pH, EC, lime, organic matter, total N, the available P, K, Ca, Mg, Na, Zn, Fe, Mn, Cu and B values are 7.45, 0.87 mS cm-1, 2.28%, 1.28%, 0.078%, 14.92 mg kg-1, 344.84 mg kg-1 2171.68 mg kg-1, 129.01 mg kg-1, 47.09 mg kg-1, 1.25 mg kg-1, 1.82 mg kg-1, 4.52 mg kg-1, 1.61 mg kg-1 and 0.71 mg kg-1 detected in B0 (control) application. The highest germination rate in wheat seeds was found in B2 with 95.41% and the lowest germination rate was found in B0 applications with 90.12%. It was determined that the effects of biochar applications on the fresh and dry weight of the plant were the highest in B2 application (11.42 and 2.21 gr pot-1) and the lowest values in B0 application (10.01 and 1.93 gr pot-1), respectively. It was detected in 09 mg kg-1, 1.25 mg kg-1, 1.82 mg kg-1, 4.52 mg kg-1, 1.61 mg kg-1 and 0.71 mg kg-1 B0 (control) application. The highest germination rate in wheat seeds was found in B2 with 95.41% and the lowest germination rate was found in B0 applications with 90.12%. It was determined that the effects of biochar applications on the fresh and dry weight of the plant were the highest in B2 application (11.42 and 2.21 gr pot-1) and the lowest values in B0 application (10.01 and 1.93 gr pot-1), respectively. It was detected in 09 mg kg-1, 1.25 mg kg-1, 1.82 mg kg-1, 4.52 mg kg-1, 1.61 mg kg-1 and 0.71 mg kg-1 B0 (control) application. The highest germination rate in wheat seeds was found in B2 with 95.41% and the lowest germination rate was found in B0 applications with 90.12%. It was determined that the effects of biochar applications on the fresh and dry weight of the plant were the highest in B2 application (11.42 and 2.21 gr pot-1) and the lowest values in B0 application (10.01 and 1.93 gr pot-1), respectively. [ABSTRACT FROM AUTHOR]

Water bodies in cities often suffer from intense eutrophication due to excessive nutrient addition. Hence, the restoration of a eutrophic water body to its original healthy state is crucial. Therefore, this research investigated the possible use of polyaluminium chloride (PAC) to restore a shallow pool in Thailand. A dosage of PAC at 30 g/m² was applied as slurry in a shallow pool in 2021. Water quality and sediment properties were monitored before, during, and after the application of PAC (four consecutive weeks). The results revealed that before the application of PAC, this shallow pool was hypereutrophic (mean total nitrogen of 0.74±0.32 and mean total phosphorus of 3.24±0.88 mg/l). Mean chlorophyll a was exceptionally high (887.45±48.33 µg/l). The predominant species were Spirulina sp. and Microcystis sp. After the application of PAC, the water quality parameters improved. The total phosphorus, chlorophyll a and turbidity were reduced significantly (p<0.05), and the transparency depth was enhanced. Furthermore, intact phytoplankton cells were shifted from cyanobacteria to green algae. Flocs were observed in the surface water and on the sediment. This method proved to be practical to use, low in operational cost, and did not affect freshwater fauna due to its low toxicity. [ABSTRACT FROM AUTHOR]

Continuous use of chemical fertilizers and farming practices in rice fields would reduce nutrient availability and biota population in the soil. Because soil biological linkages are sensitive to changes in soil function, changes in fauna and microbial populations can affect soil fertility. This study aimed to identify the condition of soil fertility and soil biota under various farming systems, namely organic, semi-organic, and conventional, and find the indicators that determine soil fertility index (SFI) in the research area. This research is a survey with the sampling method was purposive on the Land Mapping Unit (LMU) overlaid with thematic maps (land use, soil type, slope, and rainfall). The method analysis of SFI using Principal Component Analysis (PCA) and scoring methods were used for the effect of farming systems using One-way, continued by DMRT, and determinant factor using Pearson's. Correlation. The results illustrated that soil fertility was a moderate category. The highest SFI was in organic rice fields (0.69), then in semi-organic (0.62), and the lowest fertility was in conventional (0.59). Organic farming also showed the best soil biota conditions (0.27 individuals/liter of earthworms and 0.755 μ/g of microbial C biomass) compared to semi-organic (0.15 individuals/liter, 0.508 μ/g microbial C biomass) and conventional farming (0.11 individuals/liter, microbial biomass C 0.325 μ/g). Soil fertility and soil biota are positively correlated, meaning that the higher the soil fertility, the higher the density of soil biota. The soil indicators most determining fertility are total N, P-available, K-available, CEC, and organic C. [ABSTRACT FROM AUTHOR]

Spatial patterns of leaf carbon (C), nitrogen (N), and phosphorus (P) stoichiometry play a pivotal role in the comprehension of terrestrial ecosystem dynamics, nutrient cycling, in responses to contemporary global climate change, and the evolutionary trajectories of leaf morphology and function. These patterns are not only solely shaped by plant and community composition, but also are profoundly influenced by environmental factors. Therefore, there is a compelling need for an in-depth investigation into individual species to discern the intricate impacts of soil and climate on leaf stoichiometry. In this study, we assessed the C, N, and P concentrations of mature leaves from 20 Phyllostachys propinqua populations in the urban forest across northern China covering a substantial latitudinal gradient. Our findings revealed that the average leaf concentrations of C, N, and P in P. propinqua were recorded at 0.46 g g−1, 23.19 mg g−1, and 1.40 mg g−1, respectively. Notably, we observed that leaf C and P concentrations, as well as the C:N ratios, exhibited significant increases with rising latitude. Conversely, leaf N concentrations and N:P ratios exhibited a marked decline with increasing latitude. These patterns were primarily driven by climate factors such as mean annual temperature (MAT) and lowest temperature (LT). In contrast, we found that only leaf C concentrations were correlated with soil N levels. These results underscored the differential spatial distribution of leaf C, N, and P stoichiometry in urban forest across northern China, predominantly instigated by climatic factors, particularly in regions characterized by lower temperatures. Our findings further suggest that P. propinqua enhances its adaptability to low-temperature environments by elevating leaf C and P concentrations. [ABSTRACT FROM AUTHOR]

Earthquakes are environmental disturbances affecting ecosystem functioning, health, and biodiversity, but their potential impacts on plant--soil interface are still poorly understood. In this study, grassland habitats in areas near and away from the seismo-fault in Madou, a region typical of alpine conditions on the Qinghai-- Tibetan Plateau, were randomly selected. The impacts of earthquake on soil properties and plant nutrient content in the short term were emphasized, and their potential relationships with community diversity and productivity were examined. According to the findings of the study, the Maduo earthquake led to a decrease in soil nutrient content in alpine grassland ecosystems, especially soil TC, TN, TP, TCa, AP, AK, NH4 +-N, and SOC, and inhibited the absorption of N, Ca, and Mg nutrients by plants. In addition, the diversity and productivity of communities were affected by both direct and indirect earthquake pathways. The negative impacts of seismic fracture on soil structure had the most significant direct impact on plant community diversity. Earthquakes also indirectly reduced community productivity by reducing the soil N content and inhibiting the absorption of plant nutrients. Our findings suggested that earthquakes could potentially decrease the stability of the alpine grassland ecosystem on the QTP by affecting nutrient availability at the plant--soil interface. [ABSTRACT FROM AUTHOR]

Fungal endophytes are harboured in the leaves of every individual plant host and contribute to plant health, leaf senescence, and early decomposition. In grasslands, fungal endophytes and their hosts often coexist with large herbivores. However, the influence of grazing by large herbivores on foliar fungal endophyte communities remains largely unexplored. We conducted a long-term (18 yr) grazing experiment to explore the effects of grazing on the community composition and diversity of the foliar fungal endophytes of two perennial grassland species (i.e., Artemisia capillaris and Stipa bungeana) across one growing season. Grazing significantly increased the mean fungal alpha diversity of A. capillaris in the early season. In contrast, grazing significantly reduced the mean fungal alpha diversity of endophytic fungi of S. bungeana in the late season. Grazing, growing season, and their interactions concurrently structured the community composition of the foliar fungal endophytes of both plant species. However, growing season consistently outperformed grazing and environmental factors in shaping the community composition and diversity of both plant species. Overall, our findings demonstrate that the foliar endophytic fungal community diversity and composition differed in response to grazing between A. capillaris and S. bungeana during one growing season. The focus on this difference will enhance our understanding of grazing's impact on ecological systems and improve land management practices in grazing regions. This variation in the effects of leaf nutrients and plant community characteristics on foliar endophytic fungal community diversity and composition may have a pronounced impact on plant health and plant–fungal interactions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study was carried out to determine the effects of different growing media (peat + perlite, cocopeat, hazelnut husk, rock wool) and different humic acid doses (2, 4, and 8 ml L-1) on tomato plant growth. The performance of the seedlings from planting to fruit set was evaluated to determine the growth of the tomato plant. For this purpose; stem diameter (mm), plant height (cm), leaf number, first flowering, first fruit set, total plant dry weight (g), root volume (m³), and relative growth rate (g cm-2 days-1) parameters were examined. According to the results, the highest stem diameter of 15 mm was obtained in the hazelnut husk media at a dose of 4 ml L-1 of humic acid. As a result, while the best root growth was obtained at 2 ml L-1 humic acid doses in peat-perlite media, the fastest growth and N (3.33%), P (0.58%) and K (3.91%) content were obtained at 8 ml L-1 humic acid doses in cocopeat media. The best leafing, flowering and fruit set were obtained in hazelnut husk media with 2 ml L-1 humic acid doses. As a result, the highest relative growth rate (0.064 g cm-2 days-1) was determined at 8 ml L-1 doses of humic acid applied in the cocopeat media. [ABSTRACT FROM AUTHOR]

Acid soil syndrome leads to severe yield reductions in various crops worldwide. In addition to low pH and proton stress, this syndrome includes deficiencies of essential salt-based ions, enrichment of toxic metals such as manganese (Mn) and aluminum (Al), and consequent phosphorus (P) fixation. Plants have evolved mechanisms to cope with soil acidity. In particular, STOP1 (Sensitive to proton rhizotoxicity 1) and its homologs are master transcription factors that have been intensively studied in low pH and Al resistance. Recent studies have identified additional functions of STOP1 in coping with other acid soil barriers: STOP1 regulates plant growth under phosphate (Pi) or potassium (K) limitation, promotes nitrate (NO3-) uptake, confers anoxic tolerance during flooding, and inhibits drought tolerance, suggesting that STOP1 functions as a node for multiple signaling pathways. STOP1 is evolutionarily conserved in a wide range of plant species. This review summarizes the central role of STOP1 and STOP1-like proteins in regulating coexisting stresses in acid soils, outlines the advances in the regulation of STOP1, and highlights the potential of STOP1 and STOP1-like proteins to improve crop production on acid soils. [ABSTRACT FROM AUTHOR]

Copyright of Ege Üniversitesi Ziraat Fakültesi Dergisi is the property of Ege Universitesi, Ziraat Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Organic matter is essential in improving the physical, chemical and biological properties of soils. Thus, the organic matter is widely considered a crucial indicator of environmental quality and biodiversity. In this study, the effect of gyttja addition as a soil conditioner on some physical and chemical properties of soils formed on volcanic and serpentine parent materials was investigated. The layout of the incubation study was randomized plots with 3 replications and the study lasted for 8 months to determine the value of gyttja in improving soil quality in two different parent materials. The results showed that pH, EC, total CaCO3, soil organic matter (SOM), wet aggregate stability (WSA), structural stability index (SSI), Ca-ex, Mg-ex, Fe-ex and P-av values of volcanic soils were significantly increased with increasing gyttja addition rates, while dispersion ratio (DR), Cu-ex and Cd-ex values were decreased. Likewise, pH, total CaCO3, SOM, WSA, SSI, Ca-ex and P-av values of serpentine soils were increased with increasing gyttja rates, while DR, Mg-ex, Fe-ex, Cd-ex, Ni-ex, Mn-ex, Cu-ex and Zn-ex values were decreased. The changes in the values of soil properties were statistically significant. The results demonstrated that gyttja addition overall decreased the erosion susceptibility and heavy metal contents of serpentine and volcanic soils. Moreover, the gyttja addition ameliorated some of the chemical soil properties. Therefore, gyttja could be suggested as a soil conditioner in the remediation of problematic soils. [ABSTRACT FROM AUTHOR]

Key message: Non-structural carbohydrates are distributed and stored in various organs, enabling plants to make a trade-off between "growth" and "resistance", with temperature variation as the main driver. Non-structural carbohydrates (NSC) are important physiological indicators of carbon balance in plants and play a crucial ecological function in determining how plants respond to environmental changes. However, less is known about the mechanisms by which NSC change along the montane vertical climate belt gradient. In order to address this question, we investigated changes in NSC of 12 major tree species along the elevational gradients in the Sygera Mountains, southern Qinghai–Tibet Plateau. During the growing period (July–August) and dormant period (November–December) of the same phenological period, 64 woody plants were sampled for leaves, branches, trunks, and root organs. The contents of NSC, C, N, P, and K, and the main climatic factors were measured to detect the spatial and temporal characteristics of NSC content in woody plants in different elevations as well as their linkages. The results were as follows. (1) Plants seasonally allocate soluble sugars and starch. During the growing period, plants tend to store fewer non-structural carbohydrates to meet other carbon-demanding processes, such as growth or fruiting. During the dormant period, plants are committed to resisting stress and surviving winter through cooperative relationships (conversion of starch to soluble sugars). The physiological process of starch conversion to sugar may depend on whether starch concentration exceeds 5%. (2) The increasing NSC content of numerous tree species from the montane warm temperate belt to the alpine belt supports the "growth limitation" hypothesis, while the roots and leaf organs of woody plants have the most abundant carbon storage. (3) Plant nutrients (N, P, and K) promote the synthesis of NSC and regulate the quantity of soluble sugars and starch to establish a dynamic carbon balance in plants. (4) Plants accumulate NSC carbon pools in response to environmental stress (drought or low temperatures). "Low-temperature" stress is the primary factor limiting the growth of woody plants. Thus, temperature drives changes of NSC in woody plants across different elevations, while the physiological process of converting starch into soluble sugars (when starch content exceeds 5%, starch can be converted into soluble sugars) is an important mechanism that increases the tolerance of plants to abiotic stress. [ABSTRACT FROM AUTHOR]

Biochar, a sustainable green technology product, is essential for promoting plant development and growth. Nano biochar emerges as a promising solution for environmental sustainability. Despite its potential, the intricate dynamics between plants and nano-biochar, particularly in finger millet (Eleusine coracana), remain largely unexplored, necessitating a deeper understanding of their interaction. This study investigates the effects of carbon nitride (C3N4) nano-biochar, derived from melamine, on finger millet. A screening setup was employed with varied concentrations of C3N4: 0 µM (control), 500 µM, 1000 µM, 1500 µM, and 2000 µM. Morphological parameters of plants includes root-shoot length, fresh and dry weights, were analysed to determine the optimal dosage. Results reveal that the most effective concentration of C3N4 for enhancing finger millet growth was found to be 1000 µM. Beyond this threshold, higher doses proved to be toxic, impeding plant growth and development. This research sheds light on the unexplored relationship between nano-biochar and plant physiology, offering insights crucial for sustainable agricultural practices.

Sulfur (S) is the fourth most essential nutrient after nitrogen (N), phosphorus (P), and potassium (K) with a direct role in amino acid syntheses, such as methionine, cysteine, and N assimilation. Potato is a fast-growing vegetable crop with a small crop cycle; therefore, nutrient applications at the appropriate time, place, rate, and source are essential. The objective was to determine the effect of different S sources on the potato tuber yield, specific gravity, external tuber quality, and internal tuber quality. This study was conducted in 2021 and 2022, and three S sources were applied at two different rates (T1, 45 kg·ha-1 ; T2, 90 kg·ha-1 ) using a 3 × 2 factorial design. Three S sources were derived from the sulfate of ammonia (AS; SO4 22 source), magnesium sulfate (EPTOP; S0 source), and gypsum (SO42- source). Three potato cultivars were used for this study (Atlantic, Satina, and Red La Soda). The total and marketable yields indicated a positive response to the application of the S sources. Gypsum and EPTOP outperformed AS, and the lower rate (T1) performed better than the higher rate (T2). In one of the trials, the maximum yield difference between AS and gypsum was 33%. The maximum specific gravity for cultivar Atlantic was found with AS and gypsum, whereas Red La Soda and Satina did not respond to any S source. We did not report the treatment effects on the external and internal disorders when weather affected them. [ABSTRACT FROM AUTHOR]

This study is conducted in Muğla Dalaman Agricultural Management Directorate (TİGEM) in 72MAY80 grain and silage maize in the trial area according to purely random trial the randomized complete block design in 3 replications in 2016. The amount of fertilizer is obtained by substracting elements determined by soil analysis from the amount of plant nutrients required for corn yield in -1 in 950 kg. (-1 in 41.5 kg urea). The aim of this research is to determine whether fertilizer application at 4 different rates including the reduction of fertilizer application required for corn yield -1 in 950 kg. by 40% (-1 in 24.95 kg urea) and increasing it by 40% (-1 in 58.1 kg urea) and manufacturer application (-1 in 60 kg urea, -1 in 32,3 kg, 15-15-15 and -1 in 14 kg. KNO3) has an effect on the yield of corn plant and the element content of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), boron (B) and molybdenum (Mo) in the leaf. The urea applied to the soil from the base, 15-15-15, fertilizers are given to the band with the sowing seeder. The urea fertilizer used as a top fertilizer in trial plots and KNO3 fertilizer has been applied with drip irrigation system at 3 different times. According to the research results, the effect of applying fertilizer to the soil according to -1 in 950 kg. corn yield, 40% reductions and 40% increases in fertilizer application, and manufacturer application on the yield of corn and the concentration rate of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), copper (Cu), zinc (Zn), manganese (Mn), boron (B) and molybdenum (Mo) elements in the leaf is found to be statistically significant (p<0.01). The highest yield in corn plant is achieved in the application of manufacturer (-1 in 1.367,0 kg) and the application of increasing the amount of fertilizer by 40% (-1 in 1357.0 kg), fertilizer application according to -1 in 950 kg corn yield (-1 in 1225.3 kg), respectively, whereas, the lowest yield is achieved in the application of reducing the amount of fertilizer by 40% (-1 in 991.0 kg). Moreover, the total amount of fertilizer used in trial plots is calculated according to the fertilizer costs in 2016 and the price spent on fertilizer is determined in Turkish Liras (TL) and this price is divided by the 2016 corn kg price and subtracting the amount of corn obtained from the yield, and net yield is obtained excluding the fertilizer cost. [ABSTRACT FROM AUTHOR]

One of the reasons for the decrease in soil fertility is the decrease in organic matter content with agricultural activities. The addition of organic C such as pyrolysis process products has a significant effect on the development of soil physical, chemical and biological properties. In this study, the effects of biochar and liquid organic fertilizer obtained from urban wastes on soil properties and plant nutrient content were compared with NPK fertilizer application. Two different studies were carried out incubation and greenhouse studies. Changes in soil properties and plant growth were determined. According to the results obtained; significant increases were determined in soil pH and EC (electrical conductivity) values, NH4-N, NO3-N, available K, Ca and Na content with increasing levels. However, extractable P and DTPA (diethylenetriaminepentaacetic acid) extractable microelement contents decreased depending on the time. The changes in soil heavy metal content were not found to be statistically significant. Increasing application biochar and organic fertilizer levels significantly affected plant dry weight and nutrient content. The results obtained in some of the parameters evaluated were in the same group as the NPK applications. It is necessary to determine the appropriate application levels together with the application of biochar with NPK. [ABSTRACT FROM AUTHOR]

Soil incubation and pot experiments were conducted to follow the sorption processes of added phosphorus (P) fertiliser using the radioisotope tracer technique. Increasing doses of P fertiliser (40, 80, 160, 320 mg P/kg soil) were added to Chernozem and Arenosol and incubated for 1, 3, and 13 weeks. After incubation, perennial ryegrass (Lolium perenne L.) was sown in one group of pots, and the experiment had been continuing for another 9 weeks. The yield, grass P uptake, isotopically exchangeable (PIE), water-soluble (PW), and ammonium lactate soluble phosphorus (PAL) fractions of soils were measured. On Chernozem, plant P uptake, PIE, PW and PAL were significantly less in the case of the longest incubation period compared to shorter incubations. This suggests a transformation of P into tightly sorbed form. On Arenosol, there were only small changes in the parameters as the incubation period increased, suggesting less intense P transformation to tightly sorbed form. The PW/PIE ratio enhanced with increasing P-doses, and the ratios were higher on Arenosol. On Arenosol, the higher P doses caused a greater increase of PW than on Chernozem. The PIE + PW showed a good correlation with plant P uptake proving this value can be a good indicator of plant-available phosphorus.

Copyright of Ege Üniversitesi Ziraat Fakültesi Dergisi is the property of Ege Universitesi, Ziraat Fakultesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High temperature (HT) severely limits rice production, but effective measures can reduce the adverse effects of HT. A 2-year experiment was conducted involving five sowing dates to investigate the effects of potassium dihydrogen phosphate (KH2PO4), salicylic acid (SA), and the sowing date on the physiological characteristics, yield and quality of rice subjected to HT. Under ambient HT conditions (daily average temperature ≥ 30 °C for ≥ 3 days or maximum temperature ≥ 35 °C for ≥ 3 days), KH2PO4 (KP1-KP2: 22.05 and 36.75 mmol L−1), SA (SA1-SA2: 0.5 and 1.5 mmol L−1), and their combinations were applied to leaves from the late-booting stage to the flowering stage, with deionized water as a control (CK). Compared with CK, KP1, KP2, SA1, KP1 + SA1, and KP2 + SA1 alleviated the adverse effects of HT on the number of grains per panicle, seed set, and yield, among which SA1, KP2 + SA1, and KP1 were the best. The antioxidant enzyme (superoxide dismutase, peroxidase, and catalase) activities, levels of osmotic protective substances (soluble sugars, soluble proteins, and proline), and chlorophyll content were increased and the malonaldehyde content and leaf temperature were decreased in the SA1, KP2 + SA1, and KP1 treatments. Compared with those sown on April 25 and May 5, plants sown on May 15, May 25, and June 5 had suitable temperature conditions and presented increased grain yield and quality. Therefore, the application of SA1, KP2 + SA1, and KP1 and the use of an optimal sowing date (from May 15 to June 5) increased the rice yield and quality under HT. [ABSTRACT FROM AUTHOR]

The present study was performed to determine the effects of vermicompost leachate on growth, quality, and nutrients of Sedum album seedlings under salt stress. The study was carried out in Research and Practice Greenhouse of Cankırı Karatekin University in Central Anatolia of Turkey. One-month-old seedlings are treated with or without vermicompost leachate at five various NaCl applications (0, 50, 100, 150, and 200 mM). Shoot height, shoot fresh and dry weights, aesthetic appearance score, and crown widths of 10-week-old S. album seedlings and plant nutrients were evaluated. Salt stress x vermicompost leachate interaction had a significant effect on all studied traits (P < 0.05). The study revealed that vermicompost leachate–supplemented salt concentrations improved the harmful effects of salinity stress on growth and quality traits and macro- and micronutrients of S. album. The present study highlights the consideration of the regular application of vermicompost leachate, rich in nutrient content and microbial activity, to improve the detrimental aspects of salinity in salinized soils of arid and semi-arid areas and to improve the quality of soil and plant. [ABSTRACT FROM AUTHOR]

Vegetation restoration is assumed to enhance carbon (C) sequestration in terrestrial ecosystems, where plant producers and microbial decomposers play key roles in soil C cycling. However, it is not clear how the nutrient limitation patterns of plants and soil microbes might change during vegetation restoration. We investigated the nutrient limitations of the plant and microbial communities along a natural vegetation restoration chronosequence (1, 8, 16, 31, and 50 years) following farmland abandonment in Qinling Mountains, China, and assessed their relationships with soil factors. The result showed that following natural vegetation restoration, the nitrogen (N) limitation of plant and microbial communities was alleviated significantly, and thereafter, it began to shift to phosphorus (P) limitation at a later stage. Plants showed P limitation 50 years after restoration, while microbial P limitation appeared 31 years later. The changes in plant nutrient limitation were consistent with those in microbial nutrient limitation, but soil microbes were limited by P earlier than plants. Random forest model and partial least squares path modeling revealed that soil nutrient stoichiometry, especially soil C:N ratio, explained more variations in plant and microbial nutrient limitation. Our study demonstrates that the imbalanced soil C:N ratio may determine the soil microbial metabolic limitation and further mediate the variation in plant nutrient limitation during natural vegetation restoration, which provides important insights into the link between metabolic limitation for microbes and nutrient limitation for plants during vegetation restoration to improve our understanding of soil C turnover in temperate forest ecosystems. [ABSTRACT FROM AUTHOR]

Vegetation restoration is assumed to enhance carbon (C) sequestration in terrestrial ecosystems, where plant producers and microbial decomposers play key roles in soil C cycling. However, it is not clear how the nutrient limitation patterns of plants and soil microbes might change during vegetation restoration. We investigated the nutrient limitations of the plant and microbial communities along a natural vegetation restoration chronosequence (1, 8, 16, 31, and 50 years) following farmland abandonment in Qinling Mountains, China, and assessed their relationships with soil factors. The result showed that following natural vegetation restoration, the nitrogen (N) limitation of plant and microbial communities was alleviated significantly, and thereafter, it began to shift to phosphorus (P) limitation at a later stage. Plants showed P limitation 50 years after restoration, while microbial P limitation appeared 31 years later. The changes in plant nutrient limitation were consistent with those in microbial nutrient limitation, but soil microbes were limited by P earlier than plants. Random forest model and partial least squares path modeling revealed that soil nutrient stoichiometry, especially soil C:N ratio, explained more variations in plant and microbial nutrient limitation. Our study demonstrates that the imbalanced soil C:N ratio may determine the soil microbial metabolic limitation and further mediate the variation in plant nutrient limitation during natural vegetation restoration, which provides important insights into the link between metabolic limitation for microbes and nutrient limitation for plants during vegetation restoration to improve our understanding of soil C turnover in temperate forest ecosystems.

The effects of saline water irrigation and waterlogging on the growth and nutrient contents of 19 vetiver ecotypes were investigated. Plant height, tiller number, and dry biomass were recorded at 12 months after planting. The results indicated that plant growth and development were influenced by saline water irrigation and waterlogging conditions and were different among the vetiver ecotypes. The accumulation of sodium in the shoots was higher than in the roots under salinity conditions that would be of benefit as vetiver can be used to remove salt contamination from soil or water. Under waterlogging conditions, total phosphorus had a higher concentration in the roots due to the effect of root oxygen stress on phosphorus uptake. We screened 8 vetiver ecotypes that showed salt and flood tolerance. These ecotypes would be of benefit for crop improvement with the best available plant material in our breeding program.

Phosphorus (P) is an essential nutrient for crop growth, making it important for maintaining food security as the global population continues to increase. Plants acquire P primarily via the uptake of inorganic phosphate (Pi) in soil through their roots. Pi, which is usually sequestered in soils, is not easily absorbed by plants and represses plant growth. Plants have developed a series of mechanisms to cope with P deficiency. Moreover, P fertilizer applications are critical for maximizing crop yield. Maize is a major cereal crop cultivated worldwide. Increasing its P-use efficiency is important for optimizing maize production. Over the past two decades, considerable progresses have been achieved in research aimed at adapting maize varieties to changes in environmental P supply. Here, we present an overview of the morphological, physiological, and molecular mechanisms involved in P acquisition, translocation, and redistribution in maize and combine the advances in Arabidopsis and rice, to better elucidate the progress of P nutrition. Additionally, we summarize the correlation between P and abiotic stress responses. Clarifying the mechanisms relevant to improving P absorption and use in maize can guide future research on sustainable agriculture., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Healthy soil could support plant growth by optimizing the availability of nutrients. The availability of nutrients influences the health of tea plants. Nutrient deficiencies would affect the plant physiology that exhibits the plant withering. This study aimed to define the relationship between soil nutrient availability with plant nutrient uptake. This research was conducted by managing secondary data soil chemical properties, and tea plant nutrients analyzed statistically with Pearson correlation. This study only found a significant correlation between soil pH with P and Mg uptake. Correlation results between soil nutrient and plant nutrient uptake obtained a significantly negative correlation on soil pH with P and Mg nutrients with a correlation value of pH-P (r=-0.52), pH-Mg (r=-0.52). There was no correlation between other soil nutrients and plant nutrient uptake. The results of this study can be used  to determine the dose of fertilization and the management recommendation of tea plants.

Phosphorus (P) is an essential nutrient for plant growth and reproduction. Plants preferentially absorb P as orthophosphate (Pi), an ion that displays low solubility and that is readily fixed in the soil, making P limitation a condition common to many soils and Pi fertilization an inefficient practice. To cope with Pi limitation, plants have evolved a series of developmental and physiological responses, collectively known as the Pi starvation rescue system (PSR), aimed to improve Pi acquisition and use efficiency (PUE) and protect from Pi-starvation-induced stress. Intensive research has been carried out during the last 20 years to unravel the mechanisms underlying the control of the PSR in plants. Here we review the results of this research effort that have led to the identification and characterization of several core Pi starvation signaling components, including sensors, transcription factors, microRNAs (miRNAs) and miRNA inhibitors, kinases, phosphatases, and components of the proteostasis machinery. We also refer to recent results revealing the existence of intricate signaling interplays between Pi and other nutrients and antagonists, N, Fe, Zn, and As, that have changed the initial single-nutrient-centric view to a more integrated view of nutrient homeostasis. Finally, we discuss advances toward improving PUE and future research priorities. Improving plant phosphorus acquisition and use efficiency (PUE) is required to implement a sustainable agriculture. This review discusses the plant signaling mechanisms controlling adaptation to low P nutrition and analyzes emerging data disclosing the integrated nature of nutrient homeostasis. The most recent advances toward PUE improvement and future research directions are also discussed. [ABSTRACT FROM AUTHOR]

The biogenic fraction of municipal solid waste is rich in various inorganic nutrients along with the organic content and imposes environmental threats in the absence of proper disposal techniques. To valorize the highly wet biogenic municipal waste (BMW), hydrothermal carbonization (HTC) can be an effective low-temperature treatment method. The knowledge on the distribution of the nutrients in the product phases after HTC can improve processing of BMW for minimizing environmental impacts and enabling nutrient recovery. This study aims to investigate the segregation of the inorganic nutrients (i.e. nitrogen, phosphorus, potassium, calcium, and sodium) in the hydrochar and liquid product from HTC of BMW. Experiments were performed by varying reaction temperature (190, 220, and 250 °C) and reaction time (30, 60, and 90 min) at a constant feed-to-water ratio to observe the effects of reaction conditions. Majority of the sodium (> 93%) and potassium (> 96%) were transferred to the liquid after HTC irrespective of the reaction condition. Calcium (> 50%), phosphorus (> 91%), and nitrogen (> 26%) remained mainly in the hydrochar. Multivariate analysis on the variables under consideration showed that the fate of phosphorus and nitrogen was affected by the reaction conditions remarkably. The fate of potassium, sodium, and calcium was found to be less dependent on the reaction conditions. By optimizing the reaction conditions, both liquid phase and hydrochar obtained from HTC of BMW could be potential sources of plant nutrients. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the liming materials (granule and powder) with the different form, amount and combinations and sugar beet factory waste (vinasse) on pH, mineral matter content of an acid soil and the yield and nutrition of pepper plant. The experiment was carried out in pots under greenhouse conditions. Lime required to neutralize the total acidity of the soil (6.5 from 5.50) was calculated and then the experiment subjects were determined as follows K (Control), PL (Powder Lime; %90 CaCO3, %5 MgCO3), GL (Granular Lime; %90 CaO), V(Vinasse), ¼ PL+¾ V, ½ PL+½ V, ¾ PL+¼ V, ¼ GL+¾ V, ½ GL+½ VL and ¾ GL+¼ V. To increase pH of soils, 300 kg.da-1 lime was applied and then the experiment soils were incubated for one month. N, P, K as basic fertilization was applied by mixing the soil before planting. According to the results; the most effective application in increasing soil pH was powder lime, and granular lime had the same effect with slime. The pH of the control soil with a pH of 5.50 has been increased to 6.42 with TK application and 6.41 with TK + ½ ŞL application. The applications significantly increased the total N, available P, Ca, Fe and Zn contents of the soil and the total N, P, Fe, Cu, Zn and Mn contents of the plant compared to the control. The first three applications that increase pepper yield showed a ranking as TK> ŞL> VK. According to the results, it determined that vinasse can be used as an alternative lime material in agricultural fields besides lime applications in acid reaction soils. [ABSTRACT FROM AUTHOR]

Soil incubation and pot experiments were conducted to follow the sorption processes of added phosphorus (P) fertiliser using the radioisotope tracer technique. Increasing doses of P fertiliser (40, 80, 160, 320 mg P/kg soil) were added to Chernozem and Arenosol and incubated for 1, 3, and 13 weeks. After incubation, perennial ryegrass (Lolium perenne L.) was sown in one group of pots, and the experiment had been continuing for another 9 weeks. The yield, grass P uptake, isotopically exchangeable (P[sub IE]), water-soluble (P[sub W]), and ammonium lactate soluble phosphorus (PAL) fractions of soils were measured. On Chernozem, plant P uptake, P[sub IE], P[sub W] and P[sub AL] were significantly less in the case of the longest incubation period compared to shorter incubations. This suggests a transformation of P into tightly sorbed form. On Arenosol, there were only small changes in the parameters as the incubation period increased, suggesting less intense P transformation to tightly sorbed form. The P[sub W]/P[sub IE] ratio enhanced with increasing P-doses, and the ratios were higher on Arenosol. On Arenosol, the higher P doses caused a greater increase of P[sub W] than on Chernozem. The P[sub IE] + P[sub W] showed a good correlation with plant P uptake proving this value can be a good indicator of plant-available phosphorus. [ABSTRACT FROM AUTHOR]