Phosphate Fertilizer Research Articles

Exploring the coupling mode of water and fertilizer for improving growth, fruit quality, and yield of the pear in the arid region.

Considering the pear in the arid region as the research object, single-factor testing and water-fertilizer coupling testing were conducted. The response of pear tree growth to water, nitrogen, and phosphorus was explored and provided a theoretical basis for efficient water and fertilizer management. Among them, the single-factor test set water, nitrogen, and phosphorus as the three factors, and five levels were set. Screening out W3, W4, N3, N4, P3, and P4 promoted plant nutrient uptake and fruit quality. Eight treatments were set up in the water and fertilizer coupling test: Treatment 1 (T1, W3N3P3), Treatment 2 (T2, W3N3P4), Treatment 3 (T3, W3N4P3), Treatment 4 (T4, W3N4P4), Treatment 5 (T5, W4N3P3), Treatment 6 (T6, W4N3P4), Treatment 7 (T7, W4N4P3), and Treatment 8 (T8, W4N4P4). The results showed that the leaf area index of the T1, T2, T3, and T4 treatments was significantly higher than that of the other treatments at maturity. The yield, single fruit weight, and primary fruit rate were the highest under T3 treatment. The gray correlation degree analysis of fruit quality showed that the T3 treatment had the highest degree of correlation and ranking of each fruit quality index, indicating that the T3 treatment had the highest fruit quality. The yield model showed that irrigation with 6510.06 m3 hm-2, nitrogen fertilizer with 337.5 kg N hm-2, and phosphate fertilizer with 262.5 kg P hm-2 had the best yield. A detailed investigation of pear tree growth and fruit quality showed that the T3 treatment had the best fruit growth and development performance, and the pear fruit quality was the best.

Açaí Seed Biochar-Based Phosphate Fertilizers for Improving Soil Fertility and Mitigating Arsenic-Related Impacts from Gold Mining Tailings: Synthesis, Characterization, and Lettuce Growth Assessment

Biochar represents a promising alternative for enhancing substrates and remediating contaminants in mining areas. Given that arsenic (As) and phosphorus (P) share similar chemical forms, the combination of biochar and P fertilizers may reduce As uptake, thereby mitigating As-related impacts. This study aimed to evaluate the potential of biochar-based P fertilizers in improving soil fertility and mitigating human health risks from gold mining tailings in the eastern Brazilian Amazon. Biochar from açaí palm (Euterpe oleracea Mart.) seeds was produced through enrichment with single and triple superphosphate at a ratio of 1:4, at 400 °C, and applied to mining tailings at 0.5%, 1%, and 2%. After one year of incubation, lettuce plants were grown for 70 days. Biochar reduced As absorption by lettuce and improved biomass and nutrient accumulation, resulting in improved vegetation indices. Biochar was effective in reducing non-carcinogenic As risks via ingestion of soil and plants to acceptable levels. Regression equations explained the As absorption behavior as affected by the biochar and the importance of biochar-related nutrients in reducing As stress. This study demonstrates the potential of P-enriched biochar as an amendment for As-contaminated soils, reducing As absorption, increasing P availability, and improving plant growth.

Design of Mn-based nanozymes with multiple enzyme-like activities for identification/quantification of glyphosate and green transformation of organophosphorus

A Mn-based nanozyme, Mn-uNF/Si, with excellent alkali phosphatase-like activity was designed by in-situ growth of ultrathin Mn-MOF on the surface of silicon spheres, and implemented as an effective solid Lewis-Brønsted acid catalyst for broad-spectrum dephosphorylation. H218O-mediated GC-MS studies confirmed the cleavage sites and the involvement of H2O in the new bonds. DRIFT NH3-IR and in-situ ATR-FTIR confirmed the coexistence of Lewis-Brønsted acid sites and the adjustment of adsorption configurations at the interfacial sites. In addition, a green transformation route of “turning waste into treasure” was proposed for the first time (“OPs→PO43−→P food additive”) using edible C. reinhardtii as a transfer station. By alkali etching of Mn-uNF/Si, a nanozyme Mn-uNF with laccase-like activity was obtained. Intriguingly, glyphosate exhibits a laccase-like fingerprint-like response (+,−) of Mn-uNF, and a non-enzyme amplified sensor was thus designed, which shows a good linear relationship with Glyp in a wide range of 0.49–750 μM, with a low LOD of 0.61 μM, as well as high selectivity and anti-interference ability under the co-application of phosphate fertilizers and multiple pesticides. This work provides a controllable methodology for the design of bifunctional nanozymes, which sheds light on the highly efficient green transformation of OPs, and paves the way for the selective recognition and quantification of glyphosate. Mechanistically, we also provided deeper insights into the structure-activity relationship at the atomic scale.

Synergistic recovery of aluminum phosphorus from incinerated sewage sludge ash via acid and alkaline treatment

The “phosphorus (P) crisis” has increased interest in improving P recovery methods and their efficiency. Incineration of sewage sludge ash is a recognized method for efficient P recovery, but challenges persist because of low recovery efficiency using thermochemical or biological methods and the issue of heavy-metal contaminants. Traditional wet-chemical processes, which yield calcium phosphate as the main product, are complex and costly. In contrast, aluminum (Al) phosphate (AlP) not only serves as a slow-release phosphate fertilizer but also has diverse high-value industrial applications, such as its use in battery coatings. To address these challenges, we developed a novel recovery route based on AlP extraction from Al-rich incinerated sewage sludge ash via acid leaching and alkaline precipitation. Our findings indicate that nitric acid (HNO3) achieves the highest Al leaching efficiency. The leaching kinetics of PO43− and metals follow second-order kinetics. Furthermore, pH adjustment with NaOH showed that the P precipitation efficiency from oxalic acid leachate was lower than that from hydrochloric acid, sulfuric acid (H2SO4), and HNO3 (88.0%–99.8%) because of buffering effects. These results underscore the potential of Al-rich ash for effective P recovery and considerably broaden the range of applications for P products.

Magnesium-doped biochars increase soil phosphorus availability by regulating phosphorus retention, microbial solubilization and mineralization

Despite fertilization efforts, phosphorus (P) availability in soils remains a major constraint to global plant productivity. Soil incorporation of biochar could promote soil P availability but its effects remain uncertain. To attain further improvements in soil P availability with biochar, we developed, characterized, and evaluated magnesium-oxide (MgO) and sepiolite (Mg4Si6O15(OH)2·6H2O)-functionalized biochars with optimized P retention/release capacity. Field-based application of these biochars for improving P availability and their mechanisms during three growth stages of maize was investigated. We further leveraged next-generation sequencing to unravel their impacts on the plant growth-stage shifts in soil functional genes regulating P availability. Results showed insignificant variation in P availability between single super phosphate fertilization (F) and its combination with raw biochar (BF). However, the occurrence of Mg-bound minerals on the optimized biochars’ surface adjusted its surface charges and properties and improved the retention and slow release of inorganic P. Compared to BF, available P (AP) was 26.5% and 19.1% higher during the 12-leaf stage and blister stage, respectively, under MgO-optimized biochar + F treatment (MgOBF), and 15.5% higher under sepiolite-biochar + F (SBF) during maize physiological maturity. Cumulatively, AP was 15.6% and 13.2% higher in MgOBF and SBF relative to BF. Hence, plant biomass, grain yield, and P uptake were highest in MgOBF and SBF, respectively at harvest. Optimized-biochar amendment stimulated microbial 16SrRNA gene diversity and suppressed the expression of P starvation response and P uptake and transport-related genes while stimulating P solubilization and mineralization genes. Thus, the optimized biochars promoted P availability via the combined processes of slow-release of retained phosphates, while inducing the microbial solubilization and mineralization of inorganic and organic P, respectively. Our study advances strategies for reducing cropland P limitation and reveals the potential of optimized biochars for improving P availability on the field scale.Graphical

Phosphate Fertilization Without Pasture Burning Increase Biomass Productivity and Reduce Carbon Loss

Objective: In this work we evaluate the phosphorus fertilization without burning on the biomass productivity and the reduction of carbon loss from the pasture of Brachiaria brizantha in the Brazilian Amazon. Theoretical Framework: Brachiaria brizantha is the main cultivated pasture species in Brazil. The overgrazing and no nutrient replenishment in addition to the periodical burnings are the trigger factors of a gradual degradation since the 70’s in the Amazon. That fact suggests the need for research solutions to eliminate the use of this practice for pasture management. Method: A field experiment was carried out from September to November 2015 in a completely randomized blocks design. The treatments consisted of unburned pasture treated with 0, 25, 100 and 200 kg ha-1 of phosphorus compared to the pasture burning, with 4 blocks and 20 experimental plots. The experimental plots treated with phosphorus received agronomic doses of potassium and nitrogen applied on the soil surface. After applying the treatments, including the burning, the pasture was desiccated in order to homogenize the plant emergence and growth after the period without rain from July to September. Results and Discussion: The soil fertility attributes, components of biomass productivity, partial carbon stocks and the partial carbon retained in the pasture (not lost as carbon dioxide) were quantified at 56 days after the beggining of the experimental period. In comparison to the pasture burning, the treatments alter the soil phosphorus availability and, as a result, increase the partial biomass productivity and its carbon content, reducing the loss of carbon dioxide to the atmosphere. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of pasture management without fire using. These implications could encompass on how to apply and how much of an alternative phosphate must be applied to the soil in order to supply phosphorus for B. brizantha instead of using fire as a strategy of pasture management. Originality/Value: This study contributes to the literature by highlighting the superiority of phosphorus application from alternative source allied to N and K fertilization compared to the pasture burning practice in the Southwestern Amazon. This innovative approach can be used as a base for new researches and applied in the level of cattle farmers.

Phosphate-solubilizing Inoculant Improves Agronomic Performance of Common Bean with Reduced Phosphate Fertilizer dose

Phosphate-solubilizing Inoculant Improves Agronomic Performance of Common Bean with Reduced Phosphate Fertilizer dose

Phosphorus and bioenergy recovery from anaerobic co-digestion of food waste and corn residues with digested sludge: effect of HRT and pre-treatment methods

AbstractOrganic wastes from the human ecosystem including food waste (FW), agricultural waste and digested sludge (DS) from wastewater treatment can be utilized as valuable materials in anaerobic co-digestion (AcoD) for the dual purpose of bioenergy production and phosphorus (P) recovery through a chemical precipitation process. In this study, AcoD using FW and corn residues (CS) with DS for simultaneous sustainable phosphate release and biogas production were investigated. Different hydraulic retention times (HRT) of 10, 20, and 30 days were investigated, and FW was grinded, while CS pre-treatment methods including physical (FWCS), chemical (FWCS-Chem), and thermal (FWCS-Temp) were considered. The substrates of FW and CS compositions were conducted with a total organic loading of 6 g volatile solids (VS)/L/d (5 FW/1 CS) with a carbon-to-nitrogen ratio (C/N) of 24. The results indicate that FWCS-Chem showed the highest cumulative biogas production simultaneously with P release at HRT 20 days with 7279 L/m3 and 29.67%, respectively. Moreover, the effluent from all digesters exhibited a Mg/P ratio above 1, suitable for struvite precipitation without an external Mg source. Accordingly, FW, FWCS, and FWCS-Chem achieved P recovery rates of 63.64%, 69.75%, and 70.19% at 20-day HRT, with corresponding P contents in solids of 9.45, 9.43, and 8.29%, respectively. These values are comparable to commercial phosphate fertilizer containing 8.80% P. Moreover, incinerating the precipitating solids offers high-quality P concentrations in solids of up to 15.52, 16.32, and 16.31%, respectively. Hence, 20-day HRT was found to be the optimal condition for FW, CS, and DS for anaerobic co-digestion, resulting in the highest biogas production, P release, and maximum financial return for P recovery. Graphical abstract Phosphorus and bioenergy recovery from anaerobic co-digestion of food waste and corn residues with digested sludge.

Effects of phosphate fertilization and sulfadiazine on plant growth, root morphology, nitrogen and phosphorus uptake of soybean and maize

Low soil phosphorus (P) availability is a limiting factor for crop production. Application of livestock manure as organic fertilizer can increase soil P availability, but may cause soil contamination with antibiotics such as sulfadiazine (SD), thus adversely affecting plant growth and nutrient uptake. The effects of P (0 and 50 mg kg−1) and SD (0, 1, 10, and 100 mg kg−1) levels on plant growth, root development, and nitrogen (N) and P uptake of maize and soybean were examined in a pot experiment using a loess soil as the test soil. High levels of SD considerably inhibited plant growth of both crops. Both P fertilization and SD negatively affected root development of both crops, especially at higher SD levels. For both crops, the average root diameter and the proportion of thick roots increased with increasing soil SD level. When soil SD level was ≤10 mg kg−1, the effects of P fertilization and SD on plant N and P concentrations, and N:P, N- and P-utilization efficiency were not significant in most cases. The effects of SD on plant N and P nutrition could not be of a great concern when soil SD level was ≤10 mg kg−1. Overall, soil SD pollution could reduce plant biomass and inhibit root development of soybean and maize, with a stronger effect on root development than on plant biomass at a high soil SD level (≥10 mg kg−1). In agricultural production, attention should be paid to soil SD pollution via manure application.

An eco-friendly approach harnessing Trichoderma lixii ORT2 for reducing chemical phosphatic fertilizer dependency and groundwater phosphorus management through integrated in silico, in vitro and omic studies

Groundwater pollution has become an escalating global issue, with excessive application of phosphorus (P) fertilizers emerging as a major contaminant. The overuse of chemical phosphatic fertilizers has intensified the problem of P infiltration into water table, compromising soil health and exacerbating groundwater pollution. This underscores the urgent need to explore sustainable alternatives to chemical fertilizers to safeguard groundwater and soil health. The enzyme alkaline phosphatase (ALP) plays important role in efficient P-solubilization achieved by Trichoderma sp. a soil fungus known for its gradual transportation of P from fixed sources to plants. This mechanism not only minimizes P leaching into groundwater but also reduces dependency on fertilizers. To investigate the active role of fungal ALP in P-solubilization, amino acid/gene sequences of enzyme from 20 Trichoderma strains were retrieved from NCBI. Molecular docking revealed strong catalytic interaction (−6.93 kcal/mol) between complex-bound P and the ALP, involving two hydrogen bonds and key residues Gln286 and Arg340. To confirm ALP-mediated P-solubilization, 12 newly isolated Trichoderma spp., were assessed in vitro using media amended with tri-calcium phosphate (TCP), zinc phosphate (Zn3(PO4)2), or ferric phosphate (FePO4) as sole phosphorus source. Trichoderma lixii ORT2 demonstrated highest P-solubilization, yielding 547.40 μg/mL phosphate from TCP, 538.6 μg/mL from Zn3(PO4)2, and 423.45 μg/mL from FePO4, in 72 h. Solubilization was accompanied by simultaneous expression of ALP and siderophore in the same aliquot. TCP induced maximum expression of ALP (9.47 U/mL), followed by Zn3(PO4)2 and FePO4 showing 8.65 and 5.64 U/mL, respectively, in culture filtrates at 72h, that was further confirmed through proteomic analysis. FESEM micrographs confirmed P binding and biosorption into fungal mycelia as P-globules. Furthermore, Cicer arietinum inoculated with Trichoderma lixii ORT2 bio-formulations showed significant enhancement in growth parameters in TCP amended soil as compared to di-ammonium phosphate (DAP). The integrated approach of microbial P-solubilization and further utilization by plants for their growth as major nutrients merges microbial and phyto-remediation to address sustainability issues related to the management of soil health and phosphorus contamination. This strategy aims to substitute chemical phosphatic fertilizers, which are significant contributors to rising dissolved total phosphorus (DTP) in groundwater. This approach directly supports SDG 6 by reducing P leaching and improving groundwater quality, ensuring sustainable water and sanitation management for all.

Monitoring dynamics of biocrust rehabilitation in acid-saturated desert soils

The study explores the aftermath of a wastewater reservoir failure in a phosphate fertilizer industry, resulting in the release of acidic water containing phosphorus and sulfate compounds into the Ashalim stream’s Nature Reserve in the Judean desert, which affected the soil surface biological crusts (biocrusts) layer. The study aims to examine contamination effects on biocrusts over 3 years at two research sites along the stream, compare effects between contaminated sites, assess rehabilitation treatments, and examine their impact on soil characteristics. Hypotheses suggest significant damage to biocrusts due to acidic water flow, requiring human intervention for accelerated restoration. The results indicate adverse effects on biocrust properties, risking its key role in the desert ecosystem. The biocrust layer covering the stream’s ground surface suffered significant physical, chemical, and biological damage due to exposure to industrial process effluents. However, soil enrichment treatments, including biocrust components and organic material, show promising effects on biocrust recovery.

Phosphate fertilizers coated with phosphate-solubilising Trichoderma harzianum increase phosphorus uptake and growth of Zea mays

Phosphate fertilizers coated with phosphate-solubilising Trichoderma harzianum increase phosphorus uptake and growth of Zea mays

Phosphorous recovery from sewage sludge via chemical and thermal technologies

Phosphorus (P) recovery is important to reduce the dependence on natural and limited resources of phosphate rock, which can simultaneously prevent phosphorus discharge into the environment, thereby creating environmental issues such as eutrophication. One of the possible approaches to recycle phosphorus is to directly use sewage sludge as a fertilizer on arable land. Sewage sludge contains a high concentration of phosphorus, which can be suitable and alternative source of phosphate fertilizer. However, purification and removal of trace levels of phosphorus from the sewage sludge is necessary. In this review, information on appropriate strategies to the recovery of phosphorus from the sewage sludge through chemical treatment processes are collected from Scopus, Web of Science, PubMed and Embase to find the necessary literature on phosphorus recovery from the sludge using thermal or/and chemical treatment methods. The chemical methods such as adding calcium hydrate silicate, sulfuric acid, electrodialysis recovery, burning, hydrothermal and struvite have been explored to recover phosphorus from both sludge and sludge ash obtained from burning. The chemical/thermal methods have high efficiency for phosphorus recovery along with the simultaneous removal of heavy metals; these methods are considered promising for extracting the phosphorus from sewage sludge and ashes.

NPK fertilization for the first years of physic nut cultivated in two regions

The physic nut is an oilseed plant that has stood out as an alternative source for biodiesel. However, using it in this way requires determining the edaphoclimatic conditions and adequate fertilization to guarantee maximum productivity. This study objectived to evaluate and establish adequate rates of Nitrogen (N), Phosphorus (P), Potassium (K) to maximize the growth and productivity of physic nut in two edaphoclimatic conditions. Two experiments were performed over two consecutive years, one under Quartzarenic Neosol in the municipality of Diamantina and the other under Red-Yellow Latosol in the municipality of Governador Valadares. The treatments comprised rates of N: 0, 25, 50, 100 kg ha−1; P: 0, 35, 70, 140 kg ha−1; and K: 0, 40, 80, 160 kg ha−1. Plant growth was evaluated every 30 days until flowering. Seed and oil productivity was also assessed, with one harvest in Diamantina and two harvests in Governador Valadares. The edaphoclimatic condition of Governador Valadares was a determining factor in providing greater growth and productivity of the physic nut when compared to that of Diamantina. The application of N rates was unnecessary for the growth and productivity of the physic nut in Diamantina. Thus, phosphate fertilization was unnecessary in Governador Valadares and potassium fertilization was unnecessary for both regions. In Diamantina, 84 kg ha−1 and 87 kg ha−1 of P is recommended for growth and maximum productivity, respectively. Whereas, in Governador Valadares, 49 kg ha−1 and 55 kg ha−1 of N is recommended for growth and maximum crop productivity, respectively.

An integrated approach through controlled experiment and LCIA to evaluate water quality and ecological impacts of irrigated paddy rice.

This study used an integrated approach to mainly assess the water quality of paddy field during cultivation and quantify its equivalent ecological damages. Accordingly, an isolated pilot area with 0.6 ha and subsurface drainage pipes was prepared for flow measurement and multiple pollutant examination (DO, EC, pH, COD, TKN, TN, TP, NO3, butachlor) under controlled condition during 94 days of rice cultivation. Based on life cycle impact assessment (LCIA) database, the indices of ReCiPe (2016) were used to convert the examined nutrient and herbicide pollution. Results showed that TKN and TP were significant pollutants and reached the maximum concentrations of 7.2 and 4.9 mg/L in pilot outflow, respectively. Here, their average discharged loads were 56.2 gN/day and 45.3 gP/day. These loads equal leaching 8.5% and 9.4% of applied urea and phosphate fertilizers, respectively. The nutrient export coefficients were 8.4 kgN/ha and 6.8 kgP/ha. Nevertheless, the majority of this pollution was transferred by inflow. The net export coefficients were 0.3 kgN/ha and 2.6 kgP/ha while net leaching rates were 0.3%TN and 3.3%TP. The trend of combined ecological damages also showed that the 11-17th day of cultivation imposed the highest ecological risks. The state-of-the-art index of ecological footprint per food production estimates the equivalent ratio of lost lives by impaired ecosystem against lives saved from starvation. This index showed that 7% of the potential of produced paddy rice in this area for saving lives would be spoiled by releasing pollution to the terrestrial ecosystem in the long term. Yet, it can be enhanced as a matter of direct discharge to the freshwater. Therefore, using suitable agricultural operations or improving farm management practices for pollution abatement or assimilation potential is highly recommended.

Nitrogen fertilizers affecting the efficiency of mineral and organic phosphorus fertilizers in tropical soils cultivated with maize

Most conventional phosphorous (P) fertilizers are highly soluble, which favors P retention in the solid phase of the soil, and this condition hinders P availability to plants. Alternative P fertilizers, such as organominerals and struvite, have a slow release of nutrients into the soil, which in turn favors P uptake by plants; nevertheless, soil acidification caused by nitrogen (N) fertilizers can reduce P availability in the soil. In his study, we assessed the effect of N fertilizers on P availability for maize (Zea mays) grown in tropical soils with alternative P fertilizers. An experiment was set up in columns under greenhouse conditions with maize in two cultivation cycles in two soils with contrasting textures (medium and clayey textures), two N fertilizers (calcium nitrate - CN - and ammonium sulfate - AS), three P fertilizers (triple superphosphate - TSP -, organomineral - OM - and struvite - ST), and a control treatment (without addition of P and N fertilizers). At 45 days after emergence, we measured the biomass production and the N and P contents in plants to calculate fertilization efficiency as well as the soil P content. AS promoted the highest aboveground N accumulation, whereas the highest efficiency was obtained with CN. The alternative P sources did not differ in terms of P availability when combined with both N sources. Soil textures were sensitive to fertilizer combination. Further studies are needed to assess struvite interaction with other elements in the soil and the P release kinetics to plants.

Responses of Rare and Abundant Bacterial Communities to Synergistic Phosphate Fertilization and Trichoderma Inoculation Meant to Improve Alfalfa Yields

Responses of Rare and Abundant Bacterial Communities to Synergistic Phosphate Fertilization and Trichoderma Inoculation Meant to Improve Alfalfa Yields

The supply of phosphate fertilizers affects the uptake of macronutrients and the productivity of Brachiaria cultivars during the establishment period

Phosphate fertilizer is necessary in Brachiaria species to boost fodder yield and nitrogen uptake. Know Plant response the phosphate guides nutrient dosing for optimal growth. The goal was to assess how phosphorus (P) dose affected forage production and macronutrient uptake in forage plants during the establishment period. The experimental design was in a 9 × 2 factorial scheme. Nine forage plants of the genus Brachiaria were evaluated: B. decumbens cv. Basilisk, B. humidícola cv. BRS Tupi, B. humidícola, B. ruziziensis, B. brizantha cvs. Marandu, BRS Piatã, Xaraés, BRS Paiaguás and hybrid (B. brizantha × B. ruziziensis) cv. BRS Ipyporã, two doses of P: 6 and 72 mg/dm−3 of P. At the lowest dose of P, the most productive forages were Paiaguás and ruziziensis. In contrast, at the highest dose of P, the forages ruziziensis, Basilisk, Piatã, Paiaguás and Xaraés were the most productive. When compared to the use of 6 mg/dm−3 P, dose of 72 mg/dm−3 P generated an increase in forage production of 803%. The greater forage production provided by the higher P content in the soil is reflected in greater uptakes of macronutrients by forages, following the decreasing order of N > K > Mg > Ca > S = P. The highest efficiencies to produce 1 g of dry matter (DM) at doses of 6 and 72 mg/dm−3 of P were observed in the Paiaguás and humidicola, respectively. In soils with more readily available phosphorus, macronutrient conversion into plant material is more effective. As a result, grasses of the genus Brachiaria generate more DM with less mineral content.

Phosphorus transformation and balancing under a long-term rice-rice cropping system in an inceptisol of India

Phosphatic fertilizers applied to soil, with time, alters into different insoluble soil phosphorus fractions. Since P fertilizers are expensive and raw material supplies are limited, it is essential to evaluate changes in phosphorus fractions and balance in soil in order to determine appropriate phosphorus fertilizer management strategies for sustainable yields. A long-term experiment (20 years) was conducted in an inceptisol with rice-rice cropping system. Soil samples were collected from six treated plots and one fallow; analyzed for phosphorus fractions using sequential extraction method. Phosphorus balance was computed. The results reveled that yield was 51.5, 112.0, 147.7 and 116.7% higher under 50% NPK, 100% NPK, 150% NPK and 100% NPK + FYM over control. Irrespective of the treatments, the abundance of the various fractions of phosphorus (P) in soil as follows: Organic P (32.4% of total P) > Calcium-P (27.76% of total P) > Mineral P (24.17% of total P) > Iron-P (6.65% of total P) > Aluminum-P (3.46% of total P) > Reductant soluble P (3.22% total P) > Occluded P (1.44% of total P) > Saloid P (0.89% total P). Phosphorus activation coefficient (%) was recorded higher under 150% NPK followed by 100% NPK + FYM > 100% NPK > 50% NPK > 100% N > control > Fallow. Hence, 100% NPK + FYM treatment has maintained phosphorus fractions in a good proportion and sustainable yields under rice-rice cropping system.

Insights into starch synthesis and amino acid composition of common buckwheat in response to phosphate fertilizer management strategies

To investigate the response and the regulatory mechanism of common buckwheat starch, amylose, and amylopectin biosynthesis to P management strategies, field experiments were conducted in 2021 and 2022 using three phosphorus (P) levels. Results revealed that the application of 75 kg hm−2 phosphate fertilizer significantly enhanced amylopectin and total starch content in common buckwheat, leading to improved grain weight and starch yield, and decreased starch granule size. The number of upregulated differentially expressed proteins induced by phosphate fertilizer increased with the application rate, with 56 proteins identified as shared differential proteins between different P levels, primarily associated with carbohydrate and amino acid metabolism. Phosphate fertilizer inhibited amylose synthesis by downregulating granule-bound starch synthase protein expression and promoted amylopectin accumulation by upregulating 1,4-alpha-glucan branching enzyme and starch synthase proteins expression. Additionally, Phosphate fertilizer primarily promoted the accumulation of hydrophobic and essential amino acids. These findings elucidate the mechanism of P-induced starch accumulation and offer insights into phosphate fertilizer management and high-quality cultivation of common buckwheat.