Application Of Phosphate Fertilizers Research Articles

Yield and return on fertilizer with root and foliar feeding of corn plants

The results of the study of the effect of root and foliar nutrition on grain yield of maize hybrids are presented. Field experiments were conducted in 2018-2020 in the zone of sufficient moisture of the Stavropol Territory. Root nutrition of plants was carried out under presowing cultivation (in spring) with ammonium nitrate and nitroammonium phosphate at a dose of 30 kg of active agent. Foliar feeding was applied in the 8-leaf phase with Vuxal Macromix fertilizer at a dose of 2.5 l/ha. Fertilizers were studied on the middle-early hybrid Mashuk 220 MV and the mid-season-ripening Mashuk 355 MV. The highest hybrid grain yield in 2018 was obtained from the leaf application of the Vuxal Makromiks fertilizer at a dose of 2.5 l/ha, the increase relative to the control of the hybrid Mashuk 220 MV was 0.89 t/ha, the hybrid Mashuk 355 MV - 1.44 t/ha. In 2019, the highest hybrid grain yield was obtained from the application of ammonium nitrate phosphate fertilizer at a dose of N30P30K30 under pre-sowing cultivation. The grain yield increase of Mashuk 220 MV hybrid was 0.78 t/ha (11.2%), of Mashuk 355 MV hybrid - 0.90 t/ha (11.7%). In 2020, the highest yield of the grain hybrid Mashuk 220 MV was obtained when feeding the plants through the leaves with the Vuxal Macromix fertilizer at a dose of 2.5 l / ha, the hybrid Mashuk 355 MV when applying ammonium nitrate phosphate fertilizer at a dose of N30 under pre-sowing cultivation, the increase amounted to respectively 0.37 t / ha (8.1%) and 0.29 t / ha (6.6%). On average for 2018-2020, the highest hybrid yields were seen with a 2.5 L/ha application of Vuxal Macromix foliar fertilizer. Increase in grain yield of the hybrid Mashuk 220 MV was 0.60 t / ha (11,0%), the hybrid Mashuk 355 MV - 0.63 t / ha (10,5%). Payback of fertilizers by grain when growing hybrid Mashuk 220 MV was higher in the variant of root feeding of plants by fertilizer Vuxal Macromix 2,5 l/ha, for 1 ruble of costs 0,90 ruble of income was received. When growing the hybrid Mashuk 355 MV with the introduction of ammonium nitrate under pre-sowing cultivation at a dose of N30, 1 ruble of costs received 1.69 rubles of income.

Hydrous Fe-Al-Zr oxide composite filled dialysis membrane tubes for phosphate desorption study from acidic soils

Phosphorus fixation by different soil components is the main problem making it less available to plants. To approximate this biological measure, a method comprising hydrous Fe-Al-Zr ternary mixed oxide (HFAZO) sorbent filled in dialysis membrane tubes (DMT) was developed. The sorbent (HFAZO), which is composed of Fe (60%), Al (25%) and Zr (15%), was synthesized via impregnation method and characterized by XRD, BET, SEM-EDX, FT-IR and FAAS. Its average crystallite size and surface area were found to be 29.59 nm and 107.53 m2/g, respectively. The phosphate desorption study was conducted on soil samples which received different phosphorous (P) treatments, 0, 50,100 and 150 mg kg−1, for 28 days of desorption time and the phosphate desorption from soil to plant was predicted. The results suggested that the phosphorus treatment and desorption time had significant effect on the amount of desorbed phosphorus. Thus, low (0.71–13.41 mg kg−1) P was desorbed from control and higher (1.87–27.84 mg kg−1) P was desorbed from soils receiving the highest P doze (150 mg kg−1) at all levels of extraction time (1–28 days) for all soil samples. The rate of desorption of P through DMT was found to be 0.0271 hr−1 and was low as compared to other findings which implies the soil samples in this study were highly acidic with high phosphorus fixing property. Generally, the present study attempts to add insight on the potential of this method for assessing phosphate desorption kinetics from acidic soil, relevant for agronomic and environmental advising of phosphate fertilizer application and use.

Phosphorus fertilizer with increased efficiency affects soybean yields

Phosphate fertilization is an important tool for achieving high yields in soybean, especially in tropical soils where phosphate fertilization efficiency is low. Fertilizers with improved efficiency, such as polymer-coated fertilizers, are one of several strategies to increase P fertilization efficiency. The objective of this study was to evaluate plant growth, leaf P content, soybean yield, and P fertilization efficiency in different seasons in response to P rates and sources. A factorial experiment (2 x 4) + 1 using two P sources (monoammonium phosphate (MAP) and Policote-coated MAP), four P rates (40, 80, 120, and 160 kg P2O5 ha-1), and the control (no P fertilization) was conducted with soybean in the 2016-2020 seasons. Phosphate fertilization increased soybean yield and was affected by P rates and sources. Soybean yield increased from 1464.7 kg ha-1, 468.4 kg ha-1, and 2297.3 kg ha-1 without P fertilization to 3,638.5 kg ha-1, 3,682.1 kg ha-1, and 3,856.7 kg ha-1, respectively, when MAP was applied at 158.0, 125.3, and 160 kg ha-1 P2O5, while when Policote coated MAP, the maximum productivity was 3,950.3 kg ha-1, 4,380.5 kg ha-1 and 4,343.0 kg ha-1 with 159.0, 160.0 and 140.1 kg ha-1 P2O5, respectively, in 2017/2018, 2018/2019 and 2019/2020 seasons. Increasing phosphate fertilizer rates decreased agronomic P use efficiency (APUE), which was mitigated by P-coated fertilizer (fertilizer with improved efficiency). Lower APUE was observed in the 2019/2020 season, likely as a result of residual effects from previous phosphate fertilizer applications

Pemanfaatan Pupuk Hayati-fosfat untuk Meningkatkan Pertumbuhan Tanaman Jagung (Zea mays L.) di Entisol

Entisols are low fertility soils that require high doses of inorganic fertilizers to support plant growth. On the other hand, it was reported that biofertilizers can be applied to support plant growth. The purpose of this study was to examine the ability of bio-phosphate fertilizers to affect plant growth. The greenhouse experiment was arranged according to a completely randomized design, consisting of five treatments of different fertilization and each treatment was repeated four times. Experimental treatments were P1) control; P2) biological-phosphate fertilizer treatment; P3) treatment of NPK fertilizers; P4) integrated fertilizer treatment of 2 combinations of fertilizers (biological-phosphate & NPK); P5) integrated treatment of 3 combinations of fertilizers (biological-phosphate, NPK & organic). The dose of NPK fertilizer is 75% of the recommended dose. The experimental soil has a sandy loam texture, pH-soil 6.01, content of C-organic1.20%, N-total 0.09%, P-available 5.68 ppm and Kdd 0.31cmol/kg. The results showed that the application of a single biological phosphate fertilizer had no significant effect on plant growth compared to the control. A significant effect was obtained on integrated fertilization, both with two combinations of fertilizers (P4) and with three combinations of fertilizers (P5). The highest plant growth rate, with reference to the total dry biomass of plant shoots and roots, was obtained in treatment P5 with plant growth rates reaching 232.14% higher than the single treatment of biological fertilizers (P2), 53.70% higher than the single treatment of NPK fertilizers (P3) and 16.35% higher than the integrated treatment of two combinations of fertilizers (P4).

INFLUENCE OF PARTIAL ROOT-ZONE DRYING ON WATER USE EFFICIENCY AND PHOSPHORUS UPTAKE OF CORN (ZEA MAYS L.) IN A GYPSIFEREOUS SOIL

Pot experiment was conducted to study the alternate and fixed partial root zone drying on irrigation water use efficiency and phosphorus absorption efficiency of corn (Zea mays L.) in a gypsiferous soil during the spring growing season. The experiment included three irrigation techniques, which were conventional irrigation (C1), alternating partial root-zone drying (APRD) and fixed partial root-zone drying (FPRD), and three levels of phosphate fertilizer application (40, 80, 120 Kg h-1), for three stages of plant growth, jointing stage (40 days from planting), booting stage (60 days from planting) and maturing stage (105 days from planting). The experiment was carried out with a complete randomized design with nine replications. Yellow corn seeds variety DKC6664 were planted on 20/3/2020. During the aforementioned growth stages, the development of the root system and vegetative parts of corn plants were studied and the water use efficiency was calculated for each growth stage. Results showed a decrease in the ratio of root to the vegetative weight under the alternating and fixed root-zone drying for the three fertilization levels and the three-growth stage (jointing, booting, maturing). The conventional irrigation treatment gave a grain yield of 40.53, 51.44 and 57.71 g pot-1 for the fertilization levels of 40, 80 and 120 kg P h-1 with a significant difference compared to alternate and fixed partial root-zone drying treatments. Alternate partial root-zone drying give the highest water use efficiency of 0.90, 0.93 and 0.98 kg m-3. Higher values of phosphorus absorption was recorded with CI treatment. The phosphorus absorption was high in the jointing and booting stages of corn growth. Phosphorous reduced some of the negative effects of water shortage on plant growth and yield and the reason for an increase in water use efficiency.

Efficiency of Phosphorus Use in Sunflower

Sunflower is an oleaginous plant of great importance worldwide that stands out in the production of edible oil and human food. The identification of differences between cultivars regarding the use of phosphorus and the production of achenes at different levels of phosphate fertilization is a viable strategy to allow its cultivation in soils with different concentrations of phosphorus, without compromising yield and reducing environmental damage associated with excessive applications of phosphate fertilizers. Thus, the objective of this study was to evaluate different levels of phosphorus fertilization and sunflower cultivars regarding the efficiency of phosphorus use in two agricultural crops. The experimental design was in randomized blocks with four replications in split-plots, where four doses of phosphorus (50, 100, 150, and 200 kg ha−1 of P2O5) were allocated in the plots, and in the subplots three sunflower cultivars (Aguará 06, Altis 99, and BRS 122). The phosphorus use efficiency of sunflower cultivars was estimated through agronomic efficiency, vegetative efficiency, agrophysiological efficiency, apparent recovery efficiency, and utilization efficiency. The dose of 50 kg ha−1 of P2O5 provided the best phosphorus efficiency indices for the different sunflower cultivars in the two studied crops. Cultivar Aguará 06 was more efficient in conditions with P2O5 supply below 150 kg ha−1, regardless of the crop. Sunflower cultivars had the best efficiency indices of phosphorus applied in the 2016 harvest.

Combined nitrogen and phosphorus management based on nitrate nitrogen threshold for balancing crop yield and soil nitrogen supply capacity

An appropriate combined nitrogen (N) and phosphorus (P) fertilization strategy is essential for obtaining sustained higher grain yields while maintaining soil fertility. In this study, a long-term split-plot design farmland experiment (initiated in 2009) with five N fertilizer rates combined with four P fertilizer rates was established during 2016–2019 to determine an appropriate nitrate-N (NO3-N) threshold in an intensive managed wheat–maize double cropping system. A fertilization strategy was then proposed based on the NO3-N threshold to balance the crop yields and soil nitrogen supply capacity. The results showed that N fertilizer increased the accumulated NO3-N, and the combined application of phosphate fertilizer with each N rate reduced the accumulated NO3-N to different degrees. The residual soil NO3-N reached a steady-state soil N pool balance after long-term application of N at 150–225 kg ha−1 combined with P at 60–120 kg ha−1. The residual NO3-N threshold in the root zone (0–100 cm soil layer) was determined as about 100 kg ha−1 at the crop harvest to maintain the N supply capacity and prevent leaching into the deep soil (>100 cm soil layer). The fertilization guidelines are 154 kg ha−1 for N fertilizer and 106 kg ha−1 for P fertilizer in the winter wheat season, and 162 kg ha−1 for N fertilizer and 122 kg ha−1 for P fertilizer in the summer maize growing season based on the NO3-N safety threshold. The optimized fertilizer strategy reduced the fertilizer application rate by 67 kg N ha−1 per year and the residual NO3-N by 34.2 % in the deep soil, while only reducing the average yield by 3.1 % across the crops and years. These findings provide a basis for sustainably balancing grain yields and soil nitrogen supply capacity as well as preventing nitrate pollution of farmland.

Link Between Aeration in the Rhizosphere and P-Acquisition Strategies: Constructing Efficient Vegetable Root Morphology

Excessive application of phosphate fertilizer is common in vegetable fields and causes deterioration of the rhizosphere environment, that is, the soil oxygen (O2) environment, which further constrains root morphology construction and limits vegetable yield. Nevertheless, the interaction between root morphology and the response of the rhizosphere O2 environment to vegetable P utilization has rarely been reported. Therefore, we carried out an experiment applying different concentrations of O2 generator, 10%, 30%, 50%, and 80% urea hydrogen peroxide (as pure nitrogen) instead of urea as a top dressing in the rhizosphere, to study the effect on root morphology and P adsorption, and its mechanism. We found that there were O2-deficient and P-deficient zones in the rhizosphere, and oxygenation could alleviate the rhizosphere O2 and P consumption in roots. The rhizosphere O2 concentration was maintained at approximately 250.6 μmol L−1, which significantly promoted total root length, root volume, average diameter, and root activity by 29.0%, 30.9%, 3.9%, and 111.2%, respectively. Oxygenation promoted organic P mineralization and increased the Olsen-P content in the rhizosphere. The characteristics of root morphology and increased available P in the rhizosphere jointly contributed to high P absorption and utilization, and the P use efficiency was improved by 9.3% and the shoot P accumulation by 10.9% in the 30% urea hydrogen peroxide treatment compared with CK. Moreover, this treatment also improved yield and quality, including vitamin C and the soluble sugar content. However, at a still higher O2 concentration (260.8 μmol L−1), vegetable growth exhibited O2 damage, resulting in reduced yield and quality. Our study provided new insights into constructing efficient root morphology by regulating the rhizosphere O2 environment to improve vegetable yield and quality, as well as to increase P use efficiency in vegetable fields.

Spatiotemporal variations of water quality and their driving forces in the Yangtze River Basin, China, from 2008 to 2020 based on multi-statistical analyses.

Water quality deterioration is a prominent issue threatening water security worldwide. As the largest river in China, the Yangtze River Basin is facing severe water pollution due to intense human activities. Analyzing water quality trends and identifying the corresponding driver factors are important components of sustainable water quality management. Thus, spatiotemporal characteristics of the water quality from 2008 to 2020 were analyzed by using a Mann-Kendall test and rescaled range analysis (R/S). In addition, multi-statistical analyses were used to determine the main driving factors of variation in the permanganate index (CODMn), ammonia nitrogen (NH3-N) concentration, and total phosphorus (TP) concentration. The results showed that the mean concentrations of NH3-N and TP decreased from 0.31 to 0.16mg/L and 0.16 to 0.07mg/L, respectively, from 2008 to 2020, indicating that the water quality improved during this period. However, the concentration of CODMn did not reduce remarkably. Based on R/S analysis, the NH3-N concentration was predicted to continue to decrease from 2020 to 2033, whereas the CODMn concentration was forecast to increase, highlighting an issue of great concern. In terms of spatial distribution, water quality in the upstream was better than that of the mid-downstream. Multi-statistical analyses revealed that the temporal variation in water quality was predominantly influenced by tertiary industry (TI), the nitrogen fertilizer application rate (N-FAR), the phosphate fertilizer application rate (P-FAR), and the irrigation area of arable land (IAAL), with contribution rates of 15.92%, 14.65%, 3.46%, and 2.84%, respectively. The spatial distribution of CODMn was mainly influenced by TI, whereas that of TP was primarily determined by anthropogenic activity factors (e.g., N-FAR, P-FAR). This study provides deep insight into water quality evolution in the Yangtze River Basin that can guide water quality management in this region.

Effect of Rhizobium Inoculation and Phosphate Rock Fertilizer Application on Biomass Production, Nutrient use Efficiency and Yield Parameters of Green Gram (Vigna radiata)

The research was focused on an ecologically sound and highly production of legumes particularly green gram through the application of Rhizobium and rock phosphate fertilizer. Therefore, biomass production, nutrient use efficiency and yield parameters were determined for two growing seasons (November 2019 - January 2020 and February - April 2020), at Chuka university horticultural research farm. Biological nitrogen fixation (BNF) in green grams can improve sustainable soil fertility management and increased production. In Kenya, green gram is a major source of food security particularly in Tharaka Nithi County. However, green gram yields are usually low due to low phosphorous and nitrogen levels of the soil. A factorial experiment of 2 x 2 x 2 was laid out in a randomized complete block design. There were three factors, varieties (N26-nylon and KS20-uncle), phosphate rock (0 and 30 kg P ha-1) and Rhizobium MEA 716 (0 and 100 g ha-1) making a total of eight treatments which were replicated three times. Soil sampling and analyses were done before planting and after harvesting of green grams. Data on grain yield, total dry biomass, shoot and root dry weights. Phosphorus use efficiency (PUE) and nitrogen use efficiency (NUE) were done. Data was analysed using Statistical Analysis Software (SAS). Significant means were separated using Least Significant Difference (LSD) at probability level of 5 %. Results for both wet and dry seasons indicated that variety KS20 under Rhizobium inoculation and phosphate rock fertilizer (R1P1V2) showed significantly (P<0.05) higher increase in shoot dry biomass (52.01 g plant-1), root dry biomass (7.60 g plant-1), total dry biomass (146.4 g plant-1), number of pods (84 plant-1) and yield (2158 kg ha-1). Also, there was significant (P<0.05) higher phosphorous use efficiency of 279.32 Kg/ha and nitrogen use efficiency of 1732 kg/ha in treatment R1P1V2 over other treatments. From these results it was concluded that variety KS20 (V2) performed better compared to N26 (V1) under combined application of Rhizobium and phosphate rock fertilizer. Hence, based on the findings, for sustainable and improved green gram production farmers in Tharaka Nithi County.

Designing Synergistic Biostimulants Formulation Containing Autochthonous Phosphate-Solubilizing Bacteria for Sustainable Wheat Production.

Applying phosphate-solubilizing bacteria (PSB) as biofertilizers has enormous potential for sustainable agriculture. Despite this, there is still a lack of information regarding the expression of key genes related to phosphate-solubilization (PS) and efficient formulation strategies. In this study, we investigated rock PS by Ochrobactrum sp. SSR (DSM 109610) by relating it to bacterial gene expression and searching for an efficient formulation. The quantitative PCR (qPCR) primers were designed for PS marker genes glucose dehydrogenase (gcd), pyrroloquinoline quinone biosynthesis protein C (pqqC), and phosphatase (pho). The SSR-inoculated soil supplemented with rock phosphate (RP) showed a 6-fold higher expression of pqqC and pho compared to inoculated soil without RP. Additionally, an increase in plant phosphorous (P) (2%), available soil P (4.7%), and alkaline phosphatase (6%) activity was observed in PSB-inoculated plants supplemented with RP. The root architecture improved by SSR, with higher root length, diameter, and volume. Ochrobactrum sp. SSR was further used to design bioformulations with two well-characterized PS, Enterobacter spp. DSM 109592 and DSM 109593, using the four organic amendments, biochar, compost, filter mud (FM), and humic acid. All four carrier materials maintained adequate survival and inoculum shelf life of the bacterium, as indicated by the field emission scanning electron microscopy analysis. The FM-based bioformulation was most efficacious and enhanced not only wheat grain yield (4–9%) but also seed P (9%). Moreover, FM-based bioformulation enhanced soil available P (8.5–11%) and phosphatase activity (4–5%). Positive correlations were observed between the PSB solubilization in the presence of different insoluble P sources, and soil available P, soil phosphatase activity, seed P content, and grain yield of the field grown inoculated wheat variety Faisalabad-2008, when di-ammonium phosphate fertilizer application was reduced by 20%. This study reports for the first time the marker gene expression of an inoculated PSB strain and provides a valuable groundwork to design field scale formulations that can maintain inoculum dynamics and increase its shelf life. This may constitute a step-change in the sustainable cultivation of wheat under the P-deficient soil conditions.

Effects of Green Manure Combined with Phosphate Fertilizer on Movement of Soil Organic Carbon Fractions in Tropical Sown Pasture

The application of green manure is a common way to increase the soil’s level of total organic carbon (TOC) and its fractions. However, the amount of green manure to apply and how the combined application of phosphate fertilizer affects the movement of TOC, and of its fractions, is still unclear. We conducted a column experiment with two treatments of phosphate fertilizer (with and without) and green manure (0, low amount level, high amount level). The longitudinal movement distance and accumulation amount of each organic carbon fraction were investigated after 14 days and 28 days. The results indicated that green manure, phosphate fertilizer, and incubation time affected the movement of the soil organic carbon fractions by affecting the initial quality of the green manure (TOC, cellulose, and lignin content), as well as the changes in quality. Green manure significantly increased the accumulation amount of the organic carbon fractions in the soil, and the high-level input of green manure increased the movement distance and accumulation amount of the organic carbon fractions; phosphorus fertilizer did not have a significant effect on the movement distance of the organic carbon fractions, but it did significantly affect accumulation amount. The 28-day incubation period increased the movement distance and the accumulation amount of the organic carbon fractions, with the exception of the particulate organic carbon (POC), compared to the 14-day incubation period. Taken together, these findings suggest that the high-level of input of green manure combined with the application of P fertilizer is beneficial for increasing the movement of the organic carbon fractions to the depth of the soil, and promotes their accumulation, which is an important agronomic management strategy for improving soil acidity in tropical regions.

Fertility Effects on Blueberry Gall Midge (Diptera: Cecidomyiidae) in Wild Blueberry (Vaccinium angustifolium; Ericales: Ericaceae).

Blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae) is a pest in American cranberry, Vaccinium macrocarpon Aiton (Ericales: Ericaceae) and wild blueberry, Vaccinium angustifolium Aiton (Ericales: Ericaceae), and has been observed in areas of high soil and foliar nutrient levels. New management strategies, including fertilization, will need to be altered to sustain wild blueberry production under climate change and, in turn, may impact the occurrence of this pest. The purpose of this study was to measure the effect of diammonium phosphate (DAP) fertilizer application on density of infested stems and the combined effects of fertilizer application with and without infestation on wild blueberry systems. This study was conducted at two field sites in Jonesboro and Washington, ME during 2020 and 2021. Despite increases in habitat availability (blueberry cover) for the gall midge and greater infestation density, wild blueberry production benefited from DAP application. This was shown in the number of buds per stem at both sites, as well as in stem height, flowers, green fruit, blue fruit per stem, and total yield at the Washington site. Foliar nitrogen and phosphorus levels had a significant positive linear relationship with infestation density. Growers applying fertilizers should monitor blueberry gall midge field infestation levels due to our findings that DAP fertilizer impacted infestation density and the interaction of DAP fertilizer with infestation impacted wild blueberry production.

The combined application of biochar and high phosphate fertilizer promoted the mobilization and redistribution of cadmium in rhizosphere soil

The changes of rhizosphere soil properties caused by root exudates affect the migration and morphology of cadmium (Cd). The Cd speciations in rhizosphere soil were investigated by pot experiment and adsorption experiment. Four treatments were designed: no fertilization (CK); phosphate (P) fertilizer application (PF); biochar application (BC); and combined P fertilizer and biochar application (PF+BC). After 60 days of cultivation, the content of DTPA (diethylenetriamine pentaacetate acid)-Cd in PF, BC and PF+BC treatments were significantly reduced by 17.3%, 36.2%, 23.9% compared with CK treatment, respectively. We found that the pH of rhizosphere soil was significantly lower than that of non-rhizosphere soil in all treatments. The order of pH in rhizosphere soil was BC > PF > PF+BC > CK. The content of organic acid in PF, BC and PF+BC treatments were significantly reduced by 39.8%, 71.1%, 25.3% compared with CK treatment, respectively. The rhizosphere soil in PF+BC treatment had the largest available P (36.32 mg kg−1) and the largest adsorption capacity (7409 mg kg−1). The results of Energy dispersive X-ray (EDX) mapping confirmed that Cd2+ and PO43- to form bond bridges or precipitates such as Cd3(PO4)2 on the surface of soil or biochar in PF+BC treatment. When P is sufficient, although it increases the availability of Cd, the high adsorption capacity produced by the addition of biochar can re-precipitate the Cd dissolved by organic acids.

Proteomic Analysis Dissects Molecular Mechanisms Underlying Plant Responses to Phosphorus Deficiency.

Phosphorus (P) is an essential nutrient for plant growth. In recent decades, the application of phosphate (Pi) fertilizers has contributed to significant increases in crop yields all over the world. However, low efficiency of P utilization in crops leads to intensive application of Pi fertilizers, which consequently stimulates environmental pollution and exhaustion of P mineral resources. Therefore, in order to strengthen the sustainable development of agriculture, understandings of molecular mechanisms underlying P efficiency in plants are required to develop cultivars with high P utilization efficiency. Recently, a plant Pi-signaling network was established through forward and reverse genetic analysis, with the aid of the application of genomics, transcriptomics, proteomics, metabolomics, and ionomics. Among these, proteomics provides a powerful tool to investigate mechanisms underlying plant responses to Pi availability at the protein level. In this review, we summarize the recent progress of proteomic analysis in the identification of differential proteins that play roles in Pi acquisition, translocation, assimilation, and reutilization in plants. These findings could provide insights into molecular mechanisms underlying Pi acquisition and utilization efficiency, and offer new strategies in genetically engineering cultivars with high P utilization efficiency.

Revealing the underlying molecular basis of phosphorus recycling in the green manure crop Astragalus sinicus

The use of green manure as an organic fertilizer to main crops has been widely proposed as a sustainable method for ecological restoration and increasing soil fertility in degraded environments. Given the increasing excessive application of phosphate (Pi) fertilizer and the accompanying risk of environmental pollution, a strategy is required to increase the Pi absorption efficiency of green manures with nitrogen (N)-fixing ability and further improve N–P recycling and the soil remediation effect in agroecosystems. Leguminous crops, such as milk vetch (Astragalus sinicus), are the most widely used green manure plant species. In this study, through physiological assessments of different Astragalus sinicus cultivars under Pi starvation, an elite variety, Astragalus sinicus Xinzi-1 was identified, which showed high tolerance to Pi starvation and approximately 25%–60% higher Pi content than other varieties. Comparative transcriptome analysis showed that, upon Pi starvation, the expression profiles of core genes involved in Pi transport and signaling were globally and dramatically altered in Xinzi-1. Specifically, the expression of genes encoding Pi uptake transporters and acid phosphatases in Xinzi-1 were remarkably induced under Pi deficient condition. The results showed that increasing the Pi absorption efficiency of N-fixing green manure can improve the N–P recycling efficiency and soil remediation effect of green manures. This study also provides new insights for future research on appropriate breeding guidance, variety evaluation, and field management of green manures in sustainable agroecosystems.

Feasibility of variable rate application of diammonium phosphate fertilizer to wheat crop under center pivot irrigation system

A study was conducted, on a 30 ha wheat field under a solar energy powered center pivot irrigation system in a commercial farm located 400 km north of Khartoum, Sudan, to evaluate the feasibility of variable rate fertilizer application of Diammonium Phosphate (DAP) on wheat crop based on variable soil phosphorus content. Soil phosphorus content was divided into three categories (low: 3.75 to 4.50 ppm, medium: 4.51 to 5.25 ppm and high: 5.26 to 6.00 ppm) and a GIS soil phosphorus content map of the experimental field was generated. Three variable application rates (200 kg ha−1, 160 kg ha−1 and 120 kg ha−1) of granular DAP fertilizer were determined to fit the low, medium and high soil phosphorus contents, respectively. The the DAP fertilizer rate of 200 kg ha−1 was the rate practiced for wheat production in the experimental farm.The normalized Difference Vegetation Index (NDVI), measured at different wheat growth stages using sentinel-2 satellite images, and wheat grain yield were used to evaluate the response of wheat crop to the variable DAP fertilizer application rates. Excluding the tillering stage, the results showed significant differences in the NDVI values among different soil phosphorus levels and DAP fertilizer application rates at other growth stages, including stem elongation, grain filling and maturity stages. Moreover, wheat yield results showed significant differences among different soil phosphorus contents (P > F = 0.0001) and DAP fertilizer application rates (P > F = 0.0457). On the average, the highest yield of 2.449 t ha−1 was recorded in the field areas treated with the high DAP fertilizer application rate (200 kg ha−1), where the second highest yield of 2.441 t ha−1 was observed in field areas under the medium DAP fertilizer application rate (160 kg ha−1); however, no significant differences between these two yield values. Based on these results, the total savings of the DAP fertilizer was estimated to be 792 kg (equivalent to 475.2 $) in the experimental field (30 ha), only when the medium DAP fertilizer rate (160 kg ha−1) was used in the medium and high soil phosphorus zones, saving 15.84 $ ha−1 without affecting production.

Phosphate fertilizers increase CO<sub>2</sub> assimilation and yield of soybean in a shaded environment

Two light treatments [ambient sunlight (L1) during the entire growth period and 40% shade (L2) from 40 d after sowing until 24 d after flowering] and two phosphate fertilizer treatments [no phosphate fertilizer application (P0) and a conventional phosphate fertilizer application (P1)] were used to determine how phosphate fertilizer regulates soybean [Glycine max (L.) Merr.] photosynthesis under shading. We showed that phosphorus significantly increased chlorophyll content and grain yield under shading. The light-saturated net photosynthetic rate, apparent quantum yield, maximum electron transport rate, and maximum Rubisco carboxylation rate in P1 under L2 significantly increased. Moreover, phosphate fertilizer significantly improved the electron transfer and PSII reaction center performance under shading. Therefore, phosphate fertilizer increases low light-utilization efficiency by improving PSII performance, promoting ribulose-1,5-bisphosphate regeneration, ensuring a source of carboxylate substrates, and coordinating the balance between photochemical reaction and Calvin cycle under shading.

长期施肥黄土旱塬农田土壤-微生物-植物系统碳氮磷生态化学计量特征

探讨长期不同施肥制度对农田土壤、植物生态系统的碳（C）、氮（N）、磷（P）含量及其生态化学计量比的影响，可为揭示该系统能量平衡和养分循环，实现农业生态系统元素平衡及可持续发展提供参考意义。以位于黄土高原半干旱地区的长武国家黄土高原农业生态实验站长期施肥试验为研究对象，选取不施肥（CK）、单施氮肥（N）、单施磷肥（P）、施氮磷肥（NP）、单施有机肥（M）、氮肥配施有机肥（NM）、磷肥配施有机肥（PM）、氮磷肥配施有机肥（NPM）8个处理，分析了黄土旱塬典型农田土壤-微生物-植物生态系统中C、N、P含量及其生态化学计量变化规律。研究结果表明：1）长期单施有机肥和化肥配施有机肥处理可显著提高土壤和有机质C、N、P含量。2）氮、磷肥的输入显著降低了土壤和小麦C：N、N：P，施P显著降低了有机态C：P和小麦C：P；有机肥配施对微生物生物量和小麦C：N：P的影响更为明显。3）长期有机肥配施条件下土壤养分和小麦化学计量比存在较强的相关关系。微生物生物量碳与有机C、N、P呈显著正相关，土壤微生物生物量氮与土壤N、P总量呈显著正相关，微生物生物量磷与土壤C、N、P总量含量呈显著负相关；植株碳含量与微生物生物量氮呈显著正相关，植物磷含量与土壤有机磷呈显著正相关。黄土区农田生态系统土壤TC：TP与TC：TN，TN：TP呈正相关，土壤TN：TP与有机碳和有机磷比呈正相关，植物植株C：N与BC：BP、BN：BP呈正相关。长期施肥明显改变了土壤和植物C、N、P含量及化学计量比。氮肥配施有机肥可明显提高微生物对土壤碳素的转化分解，导致有机质和微生物量的化学计量比发生变化，进而提高作物对土壤碳素的固定能力，增强植株对外源养分的输入。;To explore the effects of different fertilization systems on carbon, nitrogen and phosphorus contents and ecological stoichiometric ratio of farmland soil and plant ecosystem in a long time can provide reference for revealing the energy balance and nutrient cycle of the system and realizing the balance and sustainable development of agricultural ecosystem elements. In this study, the long-term fertilization experiment at the Loess Plateau agricultural ecology experimental station of Changwu, located in the semi-arid region of the Loess Plateau, was taken as the research object. No fertilization (CK), single application of nitrogen (N), single application of phosphate (P), single application of nitrogen and phosphate (NP), single application of organic fertilizer (M), combined application of nitrogen and organic fertilizer (NM),application of phosphate and organic fertilizer(PM), and combined application of nitrogen and phosphate and organic fertillizer were selected. The contents of C, N and P in soil, microbe and plant in typical agricultural ecosystem of the Loess Plateau were analyzed, and the change rule of stoichiometry and its influencing factors were analyzed. The results showed that:(I) compared with CK, long-term single application of organic fertilizer and fertilizer combined with organic fertilizer treatment could significantly improve the carbon, nitrogen and phosphorus content of soil and organic matter. (II) With the input of exogenous nitrogen and phosphate fertilizer, compared with CK treatment, N and P treatment significantly reduced soil and wheat C:N and N:P, respectively, and P treatment significantly reduced organic matter and wheat C:P. However, the effect of organic fertilizer combination on microbial biomass and wheat C:N:P was more obvious. (III) There was a significant correlation between soil nutrients and the stoichiometric ratio of wheat under the condition of long-term organic fertilizer application, compared with no fertilization. The results showed that long-term fertilization significantly changed soil carbon, nitrogen and phosphorus contents and stoichiometric ratio, and fertilizer combined with organic fertilizer could significantly improve soil fertility in the xeroxic farmland of loess, resulting in the change of stoichiometric ratio of organic matter and microbial biomass, which had a significant impact on the stoichiometric ratio of wheat plants.

EFFECT OF METHODS OF APPLICATION OF RHIZOBACTERIA AND PHOSPHATE FERTILIZER RATES ON GROWTH AND YIELD OF SOYBEAN [GLYCINE MAX (L). Merril] IN MAKURDI

Field experiment was carried out during the 2018 cropping season at the Teaching and Research Farm of Joseph Sarwuan Tarka University, Makurdi to determine the effect of methods of application of rhizobacteria and phosphate fertilizer rates on the growth and yield of soybean. Treatments were four rates of phosphate fertilizer (0, 20, 40, and 60 kg P2O5 ha-1) and three rhizobacteria inoculant application methods (zero, seed and soil). The crop was grown to maturity and harvested. Data collected were number of leaves, Leaf Area, Leaf Area Index, Net Assimilation Rate, Crop Growth Rate, Days to 50% flowering, Total Dry Matter, number of nodules, nodules weight, seed yield and 100 seed weight. The collected data were subjected to the analysis of variance (ANOVA) at 5 % level of probability using GenStat 17th Edition. Significant differences in means were separated using Fischers Least Significant Difference [FLSD (0.05)]. The results from the study showed that combined application of rhizobacteria and phosphate fertilizer at 60 kg P2O5 ha-1 increased leaf area index and total dry matter yield of soybean significantly (P<0.05) with leaf area index of 10.19 and total dry matter of 72 g per plant as compared to leaf area index at 0 kg P2O5 ha-1, 20 kg P2O5 ha-1, 40 kg P2O5 ha-1 (7.97, 8.93 and 9.73) dry matter at 0 kg P2O5 ha-1, 20 kg P2O5 ha-1, 40 kg P2O5 ha-1 (16.6g, 59.4g and 65.2g) per plant. The result of this study showed combination application of rhizobacteria inoculation and phosphate significantly enhanced nodulation from 43 nodules in un-inoculated control to 156 and 175 nodules per plant in rhizobacteria inoculated and phosphate treatments. The result of the study showed that combined application method of seed inoculation of rhizobacteria at 100g per 15kg of seed at 60 kg P2O5 ha-1 phosphate was more economical and had more yield benefits than single application and therefore, stand recommended.