Mineral Phosphorus Fertilizers Research Articles

Mineral phosphorus fertilization for silage corn in manured soils in the Fraser Valley, Canada

AbstractEfficient management of fertilizer phosphorus (P) is crucial for enhanced resilience of agro‐ecosystems. We assessed five rates (0, 5, 10, 15, and 20 kg P ha−1) of starter P fertilizer on silage corn (Zea mays L) yield in high‐P manured soils at eight sites in 2020 and 2021 in the Fraser Valley, Canada, monitoring soil phosphate concentrations using anion exchange membranes (AEM‐P). At the V3 and V6 (3‐ and 6‐leaf) stages, corn dry matter (DM) weight response to starter P was not significant, except at one site where the critical rate was 5 kg P ha−1. At maturity, corn DM yields were in the optimum provincial range (20–25 Mg ha−1), with the exception of two sites, one with low initial soil P concentrations and the other with waterlogged soils. These results indicate that during the growing season, phosphate supply from manure application alone was sufficient for silage corn growth. Root length and diameter were not affected by starter fertilizer, while root surface area, volume, and root DM weight decreased with increasing starter fertilizer at the V3 stage in 2020. In addition, AEM‐P increased with starter P only during the first week after application. We conclude that starter fertilizer P, at any application rate, in high‐P manured soils does not improve silage corn yield; farmers applying manure at plowing in soils with high P concentrations can reduce or eliminate starter fertilizer P without impacting silage corn yields, decreasing reliance on off‐farm P inputs, and reducing potential P loss to the environment.

Short-Term Impact of Recycling-Derived Fertilizers on Their P Supply for Perennial Ryegrass (Lolium perenne).

Various nutrient recycling technologies are currently under development in order to alleviate the dependency of non-renewable raw material for the production of mineral phosphorus fertilizers commonly used in agriculture. The resulting products, such as struvites and ashes, need to be assessed for their application as so-called recycling-derived fertilizers (RDFs) in the agricultural sector prior to commercialization. Here, we conducted a short-term (54 days) trial to investigate the impact of different phosphorus fertilizers on plant growth and the soil P cycling microbiota. Lolium perenne was grown with application of superphosphate (SP) as inorganic fertilizer, two ashes (poultry litter ash (PLA) and sewage sludge ash (SSA)), and two struvites (municipal wastewater struvite (MWS) and commercial CrystalGreen® (CGS)) applied at 20 and 60 kg P ha-1 in four replicates. A P-free control (SP0) was also included in the trial. Struvite application increased plant dry weights, and available P acid phosphatase activity was significantly improved for struvites at the high P application rate. The ash RDFs showed a liming effect at 60 kg P ha-1, and PLA60 negatively affected acid phosphatase activity, while PLA20 had significantly lower phoD copy numbers. P mobilization from phosphonates and phytates was not affected. TCP solubilization was negatively affected by mineral SP fertilizer application at both P concentrations. The bacterial (16S and phoD) communities were only marginally affected by the tested P fertilizers. Overall, struvites appeared to be a suitable substitute for superphosphate fertilization for Irish L. perenne pastures.

The Dynamics of Nitrogen Valorification in Wheat Crop under the Influence of the Used Agrofound

The study assessed the efficiency of nitrogen use in winter wheat, cultivar ‘Ciprian’ through the combined application of nitrogen with phosphorus fertilizers, between 2016 and 2021. The research was organized within ARDS Lovrin, Timiş County, Romania, under the conditions of a chernozem soil type. The experimental factors considered were: experimental factor A - year of experimentation - six years 2016-2021; experimental factor B -mineral nitrogen fertilizers, with the following graduations: 0 kg N ha-1 (control), 30 kg N ha-1, 60 kg N ha-1,90 kg N ha-1and 120 kg N ha-1; experimental factor C- mineral phosphorus fertilizers, with the following five graduations: 0 kg P ha-1 (control), 40 kg P ha-1, 80 kg P ha 1, 120 kg P ha-1 and 160 kg P ha-1. Production has been taken into consideration for NEU evaluation (Y, kg ha-1), the total nitrogen (Ntot) content (%) of thegrains, N uptake (%) in relation to the experimental factors considered. Differences in NUEs had different significance compared to each experimental factor, and the interaction between A×B, A×C and B×C factors generated differences in statistically safe conditions (p<0.05 in A×C case, and p<0.001 in A×B and B×C case).

Half of global agricultural soil phosphorus fertility derived from anthropogenic sources

The use of mineral phosphorus (P) fertilizers, often referred to as anthropogenic phosphorus, has dramatically altered the global phosphorus cycle and increased soil phosphorus fertility and crop yields. Quantifying agriculture’s reliance on anthropogenic phosphorus requires estimates of its contribution to agricultural soil fertility. Here we present a model of soil phosphorus dynamics simulating phosphorus availability in agricultural soils for individual countries from 1950 to 2017. Distinguishing between anthropogenic and natural phosphorus pools and accounting for farming practices, agricultural trade and crop–livestock recycling, we estimate that the global anthropogenic contribution to available phosphorus in agricultural soils was 47 ± 8% in 2017. Country-level anthropogenic phosphorus signatures vary according to cumulative fertilizer use and phosphorus availability in soil inherited pre-1950, with negligible influence of the trade of feed and food products. Despite different historical trajectories, we find that Western Europe, North America and Asia are similarly reliant on anthropogenic phosphorus, with nearly 60% of the total available phosphorus of anthropic origin in 2017. Conversely, anthropogenic phosphorus inputs in Africa remained low over the study period, contributing only around 30% of available phosphorus. The unequal reliance of agricultural soil fertility and food production systems on anthropogenic phosphorus resources highlights the need for a fairer management of the world’s remaining phosphate rock resources. About half of the current available phosphorus in agricultural soil globally is derived from anthropogenic sources, according to country-scale simulations of phosphorus dynamics between 1950 and 2017.

Effect of Different Doses of Phosgreen Fertilization on Chlorophyll, K, and Ca Content in Butterhead Lettuce (Lactuca sativa L.) Grown in Peat Substrate

Struvite is regarded as a promising phosphorus (P) fertilizer compared to commercial pristine mineral phosphorus fertilizers. The aim of this study was to determine the effect of Phosgreen fertilizer, with struvite as its phosphorus source, on the chlorophyll, potassium (K), and calcium (Ca) contents in lettuce grown in peat compared to superphosphate. The study was carried out as a pot experiment with different doses of P fertilization. The study presents the chlorophyll a, b, total (a + b) chlorophyll, and carotenoid contents of the lettuce plants. Significant differences in the chlorophyll a and b contents were observed between the different phosphorus applications, and this can have a direct impact on the crop yields. Significantly higher contents of both chlorophyll contents were observed under Phosgreen fertilization as well as the chlorophyll a + b content *. The results of the study on lettuce indicate a dependence of vitamin C content on phosphorus fertilizer, but with no significant increase under Phosgreen fertilization; the contents of K and Ca were not significantly dependent on the type of phosphorus fertilizer. Due to the favorable composition of Phosgreen, it may be recommended for use as a phosphorus fertilizer in the agriculture and horticulture sectors.

Recycling-derived Phosphorus Fertilizers as a Sustainable Alternative to Triple Superphosphate Fertilizers

Microbial activity is adamant for the nutrient cycling in soil. Generally, mineral phosphorus (P) fertilizer is applied to soil to improve plant growth, however, significant amounts are immobilized quickly. Mineral fertilizer can cause soil degradation, affecting the microbial community. Alternative, recycling-derived fertilizers (RDFs) need to be evaluated as suitable replacement for finite mineral P fertilizer. The impact of four RDFs (two ashes, two struvites) on the soil microbiome in comparison with a P-free control and triple superphosphate (TSP) as mineral fertilizer was investigated in a pot trial and a subsequent microcosm trial (subset of samples). For both experiments, perennial ryegrass was cultivated for 54 days. The pot trial was conducted at P fertilization rates of 20 and 60 kg P ha-1 in quadruplicates. After the pot harvest, the bulk soil was stored until the microcosm trial was conducted, using the control, TSP and the two ashes at 60 kg P ha-1 in six replicates. Struvites displayed highest P bioavailability at high P application rates in the pot trial, yielding higher biomass on average. Furthermore, P solubilization from tri-calcium phosphate was enhanced in the RDFs treatments, while the TSP treatments were negatively affected. For the microcosm trial, most probable number (MPN) analysis showed that phytate-utilizing bacterial abundance was significantly increased in one of the ashes. Non-metric multidimensional scaling (NMDS) analysis of phoD illumina sequencing data showed significant separation between all treatments of the microcosm trial. Understanding the impact of RDF application on the soil P cycle is vital to sustainable agriculture.

Mechanisms of adaptation of crop production in the regions of the Volga Federal District to the consequences of global climate change

The purpose of the study is to substantiate promising directions for adapting the crop sub-sector of the regions of the Volga Federal District (VFD) to the consequences of global climate change and mechanisms for its provision. The authors considered the natural and climatic features of the territory of the Volga Federal District of the Russian Federation, studied the structure of crop producers. The indicators of crop yields are analyzed. A list of weather risks that are most often manifested in the regions of the Volga Federal District has been determined. Data are presented on the yield losses of spring wheat in dry years in the context of the federal districts of the Russian Federation from 1950 to 2020. An idea is obtained about the change in land use parameters in the medium and long term. The results obtained served as a rationale for such adaptive mechanisms of state support for the agro-industrial complex, such as insurance of agricultural risks, subsidizing reclamation work for all categories of small businesses, and allocating additional budgetary funds for the purchase of mineral (nitrogen and phosphorus) fertilizers. It is proposed to correct the list of subjects of the Russian Federation, the territories of which are classified as unfavorable for agricultural production, and include the Saratov and Orenburg regions in it. In these regions, a significant part of the territory is occupied by a semi-desert zone, and the sharp continental climate has become more pronounced. It is substantiated that the totality of the proposed measures will contribute to the accelerated adaptation of regional agrosystems to the consequences of global climate change.

Application of mineral phosphorus fertilizer influences rhizosphere chemical and biological characteristics

ABSTRACT Soil microorganisms directly participate in phosphorus (P) cycle, which in turn affects crop yield and quality. However, how biological and chemical parameters respond to mineral P fertilizer application rates in rhizosphere soil remains unclear. Here, a pot experiment was conducted to investigate the effects of different mineral P fertilizer application rates (0, 60, 120, and 300 kg P2O5 ha−1) on soil chemical properties and bacterial community in maize rhizosphere in a Mollisol. With increasing P fertilizer rates, soil organic carbon concentration decreased, while soil Olsen P and inorganic P and organic P (Po) fractions concentrations increased. High-throughput 16S rRNA gene sequencing showed that the relative abundances of some beneficial bacteria (Anaerolinea, Anaeromyxobacter, Kaistia and Rhodobacter) significantly increased with reduced P fertilizer rates, and meanwhile those of other beneficial bacteria (Mesorhizobium, Microvirga, Rhizobacter and Skermanella) significantly decreased under high P fertilizer rates. Redundancy analysis (RDA) showed that labile Po was the main driver of the differences in bacterial community structure. Bacterial community diversity and composition significantly and indirectly affected maize yield via octacalcium-bound P, occluded Fe/Al-bound P, labile Po, and moderately labile Po. The results suggested that reducing P fertilizer rates can promote beneficial bacterial growth and increase bacterial community diversity.

Straw retention coupled with mineral phosphorus fertilizer for reducing phosphorus fertilizer input and improving cotton yield in coastal saline soils

Straw return can improve soil nutrient availability, but its interaction with phosphorus (P) fertilizer on cotton (Gossypium hirsutum L.) production and soil P availability has rarely been studied. Therefore, we carried out a four-year field trial to evaluate the effects of straw management (retention or removal) with P fertilizer (0, 22, 44, 66, 88 kg P ha–1) additions on seed cotton yield, cotton P uptake, soil fertility, and P apparent recovery efficiency (PRE) in a continuous barley–cotton rotation system in a coastal saline soil field from 2016-2019. Our results showed that the year and the interaction of P fertilization and straw management had significant effects on seed cotton yield and boll numbers, but there was no significant effects of straw management and the interaction of P fertilization and straw management on seed cotton weight per boll. An increase in P activation coefficient (14-28%) was observed due to the higher soil available P content following straw retention compared to the straw removal. Compared with straw removal, straw retention reduced mineral P fertilization by about 27-38% without affecting seed cotton yield, while increasing PRE by 14‒27% over the four years. In the 0-20 cm soil layer, straw retention reduced the Langmuir P sorption maximum (Qmax) and maximum buffer capacity (BCmax), and also increased the degree of P saturation (DPS), but it did no effect on the soil adsorption equilibrium constant (k). Straw retention significantly decreased the soil Qmax compared to straw removal under 0, 22, and 44 kg P ha–1, while no significant straw effects were found on Qmax under 66 and 88 kg P ha–1. Cotton P uptake and seed cotton yield were negatively correlated with the Qmax (P<0.01). Our results suggest that straw return may be a promising management practice to reduce mineral P fertilization without significant loss of seed cotton yield on coastal saline lands.

Tine tip width and placement depth by row-injection of cattle slurry influence initial leaf N and P concentrations and final yield of silage maize

There is an urgent need to replace mineral phosphorus (P) fertilizers placed near the maize seed at sowing with other management strategies to ensure a more environmentally friendly silage maize production and to avoid depletion of the phosphate rock reserve. The main objective of this study was to test and investigate effects of different tine geometry (operation depth and tine width) and use of the nitrification inhibitor (NI) 3,4-Dimethylpyrazole phosphate (DMPP) on early growth and final yields of maize under field conditions with the purpose of replacing mineral starter P fertilizers with row-injected liquid dairy manure (slurry). A two-year field experiment was carried out on a sandy loam and a loamy sand with moderate soil P status according to the Olsen P soil test. Cattle slurry with a NI was row-injected before sowing using newly developed goosefoot tine tips of three widths (8, 17 or 26 cm) with a roller to control injection depth. For the widest tine (26 cm) slurry was placed at 7 or 10 cm depth directly under the maize seed, and for the other tines slurry was placed at 10 cm depth. One of the placement methods was tested with and without a NI. The placement methods were compared to traditional slurry injection with random lateral positions relative to the maize row (non-placed slurry) and increasing rates of mineral P starter fertilizer with and without NI. The study showed that slurry placement using goosefoot tines of 17 or 26 cm width injected at 10 cm depth combined with a NI resulted in similar final yields (up to 17 Mg DM yield ha−1) as when using mineral P as a starter fertilizer with non-placed slurry on the sandy loam. On the loamy sand, slurry placement increased early P concentration in maize, but final yield benefitted more from the mineral P fertilizer (+ 1.6 Mg DM yield ha−1 compared to the plots receiving non-placed slurry and no mineral P fertilizer). Addition of a NI to placed slurry increased early stage maize leaf P concentration on the sandy loam and early maize leaf N concentration on the loamy sand, but not with non-placed slurry. We conclude that maize yield benefitted from row-injection with medium or broad goosefoot tines placed at 10 cm depth combined with a NI, but only on the sandy loam soil in one of two trial years. The most optimal slurry distribution by placement varied with soil type and year.

Divergent responses of tiller and grain yield to fertilization and fallow precipitation: Insights from a 28-year long-term experiment in a semiarid winter wheat system

Tillering is an important phenological stage, which is strongly related to the yield in spike components and final grain yield during winter wheat growth. Precipitation during the fallow season (fallow precipitation) influences tillering in winter wheat on the semi-arid Chinese Loess Plateau. However, little work has been done regarding tiller number changes under various types of fertilization and amounts of fallow precipitation on a long-term scale. Effects of fallow precipitation and fertilization on tiller were investigated in a winter wheat (Triticum aestivum L.) system in a 28-year field study (1990 to 2017) in a semiarid agro-ecosystem. Tiller number, spike number and grain yield were measured in four fertilization conditions: control without fertilizer (CK); mineral nitrogen fertilizer alone (N); mineral phosphorus fertilizer alone (P); mineral nitrogen and phosphorus fertilizer together (NP). Based on the long-term annual fallow precipitation, dry years (<mean annual fallow precipitation) and wet years (>mean annual fallow precipitation) were distinguished. Phosphorus fertilization alone significantly increased the mean annual tiller number (23%), and the increase in tiller number was higher in wet years (29%) than in the dry years (17%). However, nitrogen fertilization alone had little effect on mean tiller number, while nitrogen and phosphorus together significantly increased mean annual tiller number (30%), mean tiller number in wet years (45%) and mean tiller number in dry years (17%). Tiller number was significantly and positively correlated with fallow precipitation in dry years for all fertilizer treatments, whereas it was weakly and either positively or negatively correlated with fallow precipitation in wet years depending on the treatment. This study found positive correlations between tiller number and fallow precipitation in the CK and NP treatments, and it found negative correlations between tiller number and fallow precipitation in the treatments with nitrogen fertilization alone or phosphorous fertilization alone in wet years. Understanding the impacts of fallow precipitation and fertilization on tiller development shed light on ways to improve crop production in rain-fed agricultural regions.

Toward the sustainable use of mineral phosphorus fertilizers for crop production in China: From primary resource demand to final agricultural use

Sustainable phosphorus (P) management is crucial to both food security and environmental conservation. The optimization of P input from mineral fertilizers has been advocated as an effective approach to improve P use efficiency. However, strategies for maximizing P use efficiency by linking soil–crop systems and fertilizer types with the P flow, from a whole P supply chain perspective, are lacking. In this study, a meta-analysis and substance flow analysis (SFA) were employed to evaluate the effects of different mineral P fertilizer types on crop yield and P flow from rock phosphate (RP) exploitation to P use in China. Compared to single superphosphate (SSP), triple superphosphate (TSP), and calcium magnesium phosphate (CMP), a significantly higher yield was obtained when diammonium phosphate (DAP) and monoammonium phosphate (MAP) were used 2005 onwards. However, P loss, from RP extraction to application, was 24% higher for DAP and MAP than for SSP, TSP, and CMP. DAP and MAP use led to a 6% larger P footprint than SSP, TSP, and CMP use. The P use efficiency could be improved by 22%, 36%, and 40% in wheat, maize, and rice production, respectively, by integrating the soil–crop system with mineral P fertilizer types, while P loss and P footprint could be reduced by 13% and 17%, respectively. These results indicate that P use efficiency can be significantly improved by integrating mineral P fertilizer types with soil–crop systems, providing an effective approach for RP exploitation to improve P use efficiency and alleviate the overexploitation of RP.

Differentiating bacterial community responses to long-term phosphorus fertilization in wheat bulk and rhizosphere soils on the Loess Plateau

Mineral phosphorus (P) fertilizers are frequently applied to fields to support high crop yields, but long-term P input changes soil chemical and biological fertility. In the present study, based on a long-term P experiment (with three P levels (0 (P0), 50 (P50), and 100 (P100) kg P2O5 ha−1 yr−1)), we evaluated the effects of P input on the bacterial community in wheat bulk (BS) and rhizosphere (RS) soils. Compared to the control (P0), the P50 and P100 treatments significantly (P < 0.05) increased soil available P (AP) in the BS and RS, but they did not affect the numbers of observed species or diversity, and these indices were significantly lower in the RS than in the BS. Additionally, P fertilization changed the bacterial community compositions in both RS and BS, with minor changes in the RS but major changes in the BS; the bacterial community in the RS was different from that in the BS, with weaker network complexity but closer relationships among the bacterial taxa. An average of 2.95% of all the analyzed genes were involved in P metabolism, with a higher abundance in RS than in BS samples; however, no differences among the three treatments were observed in the BS or RS samples. In conclusion, long-term P fertilization had little impact on bacterial community diversity but changed the community compositions in wheat BS and RS; the changes in the bacterial community and functional profiles in the rhizosphere soil were mainly mediated by roots, which could help supply more available P to the plants.

Tracing the fate of phosphorus fertilizer derived cadmium in soil-fertilizer-wheat systems using enriched stable isotope labeling

Applying mineral phosphorus (P) fertilizers introduces a considerable input of the toxic heavy metal cadmium (Cd) into arable soils. This study investigates the fate of P fertilizer derived Cd (Cddff) in soil-wheat systems using a novel combination of enriched stable Cd isotope mass balances, sequential extractions, and Bayesian isotope mixing models. We applied an enriched 111Cd labeled mineral P fertilizer to arable soils from two long-term field trials with distinct soil properties (a strongly acidic pH and a neutral pH) and distinct past mineral P fertilizer application rates. We then cultivated wheat in a pot trial on these two soils. In the neutral soil, Cd concentrations in the soil and the wheat increased with increasing past mineral P fertilizer application rates. This was not the case in the strongly acidic soil. Less than 2.3% of freshly applied Cddff was taken up by the whole wheat plant. Most of the Cddff remained in the soil and was predominantly (>95% of freshly applied Cddff) partitioned into the easily mobilizable acetic acid soluble fraction (F1) and the potentially mobile reducible fraction (F2). Soil pH was the determining factor for the partitioning of Cddff into F1, as revealed through a recovery of about 40% of freshly applied Cddff in F1 in the neutral pH soil compared with about 60% in the strongly acidic soil. Isotope mixing models showed that F1 was the predominant source of Cd for wheat on both soils and that it contributed to over 80% of the Cd that was taken up by wheat. By tracing the fate of Cddff in entire soil-plant systems using different isotope source tracing approaches, we show that the majority of Cddff remains mobilizable and is potentially plant available in the subsequent crop cycle.

Impacts of Grinding and Acidification of Animal Bones with Coffee Wastewater on Plant Dry Matter Yield and Recovery of Phosphorus

ABSTRACT In sub-Saharan Africa, soil fertility depletion and limited access to mineral phosphorus (P) fertilizers are considered among the main constraints of crop productivity. The goal of our work is to make P fertilizer from locally available materials, thus reducing the costs due to importation and transportation for smallholder-farmers with limited financial capacities. Cattle bones collected from slaughterhouses were ground to two fineness-level, acidified using coffee wastewater (pH ~4.3), and then compared to commercially available diammonium phosphate (DAP) in a pot experiment using Zea mays (maize) and Phaseolus vulgaris (common bean). Finely ground bones increased maize and common bean dry matter yield (DMY) and P uptake compared to coarsely ground bones, but a significant interaction between grinding and acidification also suggests that acidification with coffee wastewater increased availability of bone-based P, at least two-times more DMY and P uptake under acidified finely ground bones than for non-acidified treatments. In addition, acidified finely-ground bones produced maize and common bean DMY, P uptake and P recovery efficiency that were comparable to those of DAP. These results demonstrate the utility of acidified finely ground bones to enhance crop yields, potentially serving as an alternative P-rich resource to imported and expensive fertilizers that depend on nonrenewable resources.

Diet Controls Uranium Intake and Aggravates Health Hazards

Uranium (U) is ubiquitously abundant in the environment. Significant amounts of U are applied on agricultural soils with mineral phosphorus fertilizers; thus, entering the food chain. The daily intake of U with solid food varies only slightly. It is lowest with a mixed standard diet (1.3 µg/day U) and highest with a vegan diet (2.0 µg/day U). It is the U content of tap and mineral water which determines the total U intake (1.7 – 7.1 µg/day U). Next to U speciation and amount of U entering the human body, an oversupply with phosphorus, and a critical supply with calcium and iron may amplify negative health effects. Kidneys are the prime target of a high P intake and U toxicity. The additional daily phosphorus intake by food phosphates peaked to 1000 mg/day in the last 20 years. This may add on an average 1.2 µg/day U and worst case 11 µg/day U to the solid diet. Toxicological studies suggest that damages of kidneys can be expected when the U content is as low as 0.1-0.4 µg/g U. The study provides a comprehensive overview of potential health hazards caused by dietary uranium intake in relation to nutritional habits.

Enhancing phosphorus availability, soil organic carbon, maize productivity and farm profitability through biochar and organic–inorganic fertilizers in an irrigated maize agroecosystem under semi‐arid climate

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

Reducing the amount of mineral phosphorus and potassium fertilizers by using its natural sources for Red Globe grapevines

This investigation was conducted during three successive seasons of 2016, 2017 and 2018 in a private vineyard located at Samaloute district, Minia Governorate, Egypt on Red Globe grapevines to study the possibility of reducing the amount of mineral phosphorus and potassium fertilizers by using its natural rocks when combined with organic manure (FYM), bio-fertilizers (BF) and elemental sulphur (S). The chosen vines were nine years old, grown in a clay loam soil, spaced at 1.75 x 3 m apart, irrigated under surface irrigation system, and spur-pruned, trellised by Gable supporting system and trained to quadrilateral cordon system. The results revealed the possibility of using 50<i> </i>% natural rocks of P and K + FYM + BF + S as a partial substitute of mineral phosphorus and potassium fertilizers. Application of 50 % mineral P and K + 50<i> </i>% natural rocks of P and K + FYM + BF + S exhibited the most suitable management system for achieving the best yield with its components, physical properties of clusters, improved physical and chemical berry characteristics, vegetative growth, leaf chlorophyll and mineral content of Red Globe grapevines. The treatment also improved the soil properties.

Phosphorus Availability, Uptake and use Efficiency of Barley &amp; Maize Yields as affected by Green Manures

Green manures refer to soil fertility building crops, which may be broadly defined as crops grown for the benefit of the soil.They have been use in traditional agriculture for thousands of years but today's they are still limited utilized by farmers.A Lysimeters experiment was conducted at Sakha Agricultural Research Station,Egypt to assess the effect of green manures, and phosphorus fertilizer on some soil properties, phosphors use efficiency and yields of barley (in winter season 2016/2017) following by maize (in summer 2017). The experiment was arranged in split plot design with three replicates. The main plots were devoted to green manures: control (without green manure), as Lentil plants (Lens culinaris Medikus) and as Rocket plants (Eruca sativa L.); the sub plots were arranged in four rates of mineral phosphorus fertilizers: control: (without addition),7.5, 11.25 and 15.5 kg P2O5 fed-1.The obtained results illustrated that using green manures i.e., lentil and rocket before planting barley significantly improved soil properties; increased the availability of the nutrients (NPK), and total porosity. Interaction between green manure as a rocket with mineral P-fertilizer rate at 15.5 kg P2O5 fed-1 attained the highest values of biological yield, harvest index, grain weight, and nutrients-uptake of NPK of barley and maize. The use of rocket as green manures with mineral phosphorus fertilizer at a rate of 11.25 kg P2O5 fed-1(75% of RD)maximized barley and maize yields and phosphorus use efficiency.So,the study concluded the importance of using green manures to improve soil fertility and properties and mineral phosphorus fertilizer use efficiency.

Effects of mineral phosphorus fertilizer reduction and maize straw incorporation on soil phosphorus availability, acid phosphatase activity, and maize grain yield in northeast China

ABSTRACT The partial substitution of mineral phosphorus (P) fertilizer by crop straw can mitigate its consumption and losing risk to the environment. However, the changes in soil P availability, acid phosphatase (AcP) activity, and grain yield under mineral P fertilizer reduction and crop straw incorporation remain poorly understood. This study evaluated the effects of a 20% reduction in mineral P fertilizer plus maize straw addition on soil P availability, AcP activity, and maize grain yield, as well as their relationships in a 5-year continually planted maize field in northeast China. Results showed that five years of continuous 20% of mineral P fertilizer reduction and maize straw incorporation significantly increased soil NaHCO3-Po and NaOH I-Pi concentrations, and did not decrease soil labile inorganic P concentration and grain yield compared to the treatment where 100% mineral P fertilizer was applied without straw addition. Additionally, there were significant positive correlations between soil AcP activity, labile inorganic P concentration, and grain yield, indicating AcP might play an important role in maintaining soil P availability and grain yield. Overall, the addition of maize straw can effectively replace 20% of the mineral P fertilizer and could be used as an appropriate fertilization practice in northeast China.