Availability of Organic and Inorganic Phosphorus Fractions to Wheat in Toposequences of Calcareous Soils

Abstract

Information on the availability of different soil phosphorus (P) forms is useful for crop production. Phosphorus contents of 12 Iranian calcareous soils from upper‐, mid‐, and lower‐slope positions of two arid and two semiarid toposequences were fractionated to various organic and inorganic pools, and correlations of the P fractions with wheat responses were investigated. Among the inorganic P (IP) fractions, apatite type (Ca₁₀‐P) and dicalcium phosphate equivalents (Ca₂‐P) possessed the highest and the lowest amounts of P reserve in the soils, respectively. On average, about 20% of the total P was found in organic form (OP), of which 32% was labile (LOP), 51% was moderately labile (MLOP), and 17% was nonlabile (NLOP). The amounts of the soil P fractions were considerably influenced by the positions of the soils on the landscapes. The maximum contents of soil IP, Ca₂‐P, Fe‐P (iron‐bound P), and Ca₁₀‐P were observed in the lower‐slope positions. The amount of soil available [0.5 M sodium bicarbonate (NaHCO₃) extractable] P was significantly correlated with Ca₂P (r=0.895), Fe‐P (r=0.760), and Occl‐P (iron‐occluded P) (r=0.897). Direct correlation studies, however, showed that wheat shoot dry‐matter yield (DMY) was significantly affected by the amounts of Ca₂‐P, Fe‐P, OP, LOP, and MLOP fractions both at early (4 weeks) and late (10 weeks) stages of growth. All organic and inorganic P fractions, except Al‐P (aluminum‐bound P), Ca₈‐P (octacalcium phosphate equivalents), and NLOP, also showed significant relations to the amount and/or concentration of P in wheat tissues at 4 and 10 weeks after sowing. Among the measured soil properties, the amount of organic carbon was the most affecting factor on the size of the P fractions.     

种植制度和施肥对半干旱区土壤中锰形态及有效性的影响

Manganese(Mn) deficiencies are common in soils on the Loess Plateau of China. This research provided essential information on improving Mn availability in semiarid soils through agricultural practices. Twelve cropping system and fertilization treatments were designed in a 28-year experiment. The cropping systems included long-term fallow, continuous winter wheat cropping, pea(1 year)-winter wheat(2 years)-millet(1 year) rotation(crop-legume rotation) cropping, and continuous alfalfa cropping. The fertilizer treatments under the cropping systems included no-fertilizer control(CK), application of P fertilizer(P), application of N and P fertilizers(NP), and application of N and P fertilizers and manure(NPM), but the NP treatment was excluded in the continuous alfalfa cropping system. Available Mn and Mn fractions of soil samples(0–20 and 20–40 cm depths) were measured and further analyzed quantitatively using path analyses. Results showed that the crop-legume rotation and continuous alfalfa cropping systems significantly increased available Mn compared with the fallow soil. Compared with the no-fertilizer control, manure application increased available Mn in soil of the continuous wheat cropping system. Across all treatments, the averaged content of mineral-, oxide-, carbonateand organic matter-bound and exchangeable Mn accounted for 42.08%, 38.59%, 10.05%, 4.59%, and 0.09% of the total Mn in soil,respectively. Cropping significantly increased exchangeable Mn in soil and the highest increase was 185.7% in the continuous wheat cropping system at 0–20 cm depth, compared with the fallow soil. Fertilization generally increased exchangeable and carbonate-bound Mn in soil. Carbonate-bound Mn was the main and direct source of available Mn in soil, followed by exchangeable and organic matterbound Mn. These results indicated that crop-legume rotation cropping, continuous alfalfa cropping and application of manure, have the potential to promote Mn availability in soils of rainfed farmlands.     

Dissolution of Dominant Soil Phosphorus Fractions in Phosphorus-Responsive Soils of Bihar,India: Effects of Mycorrhiza and Fertilizer Levels

We investigated the effects of Arbuscular Mycorrhiza (AM) fungi and various phosphorus (P) levels on the distribution and availability of P in dominant soils of Bihar, India. Potassium chloride (KCl)-P (labile P), sodium hydroxide (NaOH)-P (Fe-Al-bound P), hydrochloric acid (HCl)-P (Ca-bound P), and residual P (Res-P) fractions were analyzed in the soils under maize plant. Ca-bound P was the most abundant P fraction in the alkaline soils (65% of the total P) followed by neutral soil (35% of the total P), whereas it was less abundant (<4%) in the acidic soil type. Fe-Al-bound P was found to be highest for acidic soil (65% of the total P). Soils under the inoculation with Glomus mossae and control gave the highest and lowest values (15.63 mg kg^?1 and 10.74 mg kg^?1 respectively) for the labile fraction which was similar to the organically bound residual fractions of P (200.17 mg kg^?1 and 193.66 mg kg^?1 respectively. Inoculation of the soils with AM fungi leads to the redistribution of P fractions in different soils which consequently helps in improvement of available P in soil conducive for plant uptake.     

科尔沁沙地东南部植被类型变化对土壤磷素状况的影响

In the past 50 years, large areas of the Horqin sandy land were afforested to prevent desertification. Although the afforestation policy appears successful, many people now doubt whether it is suitable to plant trees with high density on the poor soils in semiarid regions. Little is known about the impacts of afforestation on the sandy soil properties, although the evaluation of these impacts is fundamental to judge the rationality of afforestation policy. Soil phosphorus （P） fractions, acid phosphomonoesterase activities, and other soil chemical properties were compared among five adjoining typical ecosystems on poor sandy soils in southeastern Horqin sandy land. The ecosystems studied are natural elm savanna, degraded grassland, Mongolian pine （Pinus sylvestris var. mongolica） plantation, Chinese pine （Pinus tabulaeformis） plantation, and mixed plantation of Mongolian pine and poplar （Populus simonii）. The results showed that organic P dominated soil P （47%-65%） was the principal source of available P. The degradation of elm savanna to grassland significantly reduced soil pH and resulted in an overall reduction in soil fertility, although slightly increased labile inorganic P. Grassland afforestation had no significant influence on soil pH, organic carbon, and total N but significantly reduced total P. Impacts of grassland afforestation on soil P fractions depended on tree species. Natural elm savanna had higher soil P conserving ability than artificial plantations. Therefore, with the aim of developing a sustainable ecosystem, we suggested that vegetations with low nutrient demand （particularly P） and efficient nutrient cycling would be more suitable for ecosystem restoration in the semiarid region.     

Potassium and magnesium in some Kenyan soils: their mineral sources and release to Ca-resin

Five soil types from Kenya were examined for their ability to release K and Mg to crops by extracting them with a calcium-saturated cation exchange resin, and for the mineral sources of K and Mg. Amounts and rates of release of exchangeable, short- and long-term reserves of K and Mg were determined. This was done for K before and after one, two and 10 wetting and drying (WD) cycles, designed to mimic the effect of the local climate on K release. The order of decreasing K and Mg contents of the soils was Muguga > > Katumani > Kampi-ya-Mawe (KYM) ∼ Ithookwe ∼ Kwale. In the case of K, wetting and drying increased the exchangeable fraction in all of the soils. The Muguga, Ithookwe and KYM soils have the capacity to release a great deal of K in the long-term, but at very different rates; the Kwale soil has few reserves and fixes K on WD.
The K and Mg contents of the soils were closely related to the mica contents of the clay + silt fractions. Exchangeable and non-exchangeable K was released from soil micas primarily by ion exchange, with some contribution to non-exchangeable K from dissolution. Release of exchangeable Mg was primarily by ion exchange, whilst that of non-exchangeable matrix Mg was by dissolution of trioctahedral mica in the clay + silt and the sand fractions of the soils. Response would be expected only to K fertilizers and only with the Kwale soil. However, all the other soils should, in the interests of good husbandry, receive maintenance dressings of K and Mg at convenient times in the crop rotation.     

Fertilizer‐use efficiency of different inorganic polyphosphate sources: effects on soil P availability and plant P acquisition during early growth of corn

Polyphosphate‐based fertilizers are worldwide in use, and their effect on crop yield is often reported to be similar to orthophosphate products, although some studies showed higher yields with polyphosphate applications. However, information on how these fertilizers may influence plant P acquisition is very limited. A pot experiment was carried out under controlled conditions with corn (Zea mays L.) growing on a sandy soil (pH 4.9) and a silty‐loam soil (pH 6.9) differing in P‐sorption properties. The objective was to evaluate phosphorus fertilizer–use efficiency (PFUE) of several polyphosphate (poly‐P) compounds (pyrophosphate [PP], tripolyphosphate [TP], and trimetaphosphate [TMP]) using orthophosphate (OP) as a reference. Focus was put on evaluating plant parameters involved in plant P acquisition, i.e., root length and P uptake per unit of root length. Furthermore, soil P availability was characterized by measuring ortho‐P and poly‐P concentrations in soil solution as well as in CAL (calcium‐acetate‐lactate) extracts. The P availability was differentially influenced by the different P sources and the different soils. In the silty‐loam soil, the application of poly‐P resulted in higher ortho‐P concentrations in soil solution. In the same soil, CAL‐extractable ortho‐P was similar for all P sources, whereas in the sandy soil, this parameter was higher after OP application. In the silty‐loam soil, poly‐P concentrations were very low in soil solution or in CAL extracts, whereas in the sandy soil, poly‐P concentrations were significantly higher. Phosphorus fertilizer–use efficiency was significantly higher for poly‐P treatments in the silty‐loam soil and were related to a higher root length since no differences in the P uptake per unit of root length among poly‐P and OP treatments were found. However, in the sandy soil, no differences in PFUE between OP and poly‐P treatments were observed. Therefore, PFUE of poly‐P compounds could be explained by better root growth, thereby improving plant P acquisition.     

Phosphorus fractions in argentine soils of different pedogenesis

Abstract

The distribution of phosphorus (P) in different organic and inorganic fractions was examined in five Argentinean soils of different pedogenesis. Soils were sequentially extracted to determine resin‐P, bicarbonate‐P, and hydroxide‐P fractions. Inorganic P (IP) predominated in all soils, specially moderately resistant IP (MRIP) in Entisol, Vertisol, and Ultisol. Both MRIP and labile IP (LIP) were important in Mollisol. Organic P (OP) was at a lower concentration in all soils and moderately resistant OP (MROP) was highest in all soils, except for the Mollisol. In intermediate evolution soils, labile P (LP) was very important, Mollisol had the highest value of LP%, and the lowest was for the Ultisol, demonstrating greater dynamics of P fractions in the Mollisol, soils of high productivity in the Pampean Prairie.     

Abiotic and biotic drivers of struvite solubilization in contrasting soils

Phosphorus (P) limitation in the coming decades calls for the utilization of alternative fertilizers in agriculture. Struvite is a promising P source, but its potential role as a fertilizer is dependent on different physical, chemical, and biological properties, which are very heterogeneous in soil, complicating the prediction of the best soil conditions for its application. Here, we evaluated the solubility of struvite in soil, its redistribution into P fractions, and its potential abiotic and biotic drivers in 62 globally distributed soils with contrasting properties through an incubation assay. We found that after 40 d, about 35% of struvite P was redistributed into soil fractions more accessible to plants and microbes. Phosphorus redistribution from struvite was driven by a complex suite of soil physical, chemical, and microbial properties as well as environmental factors that varied across soils. Soil texture played a critical role in determining the redistribution of P in struvite-amended soils in soluble (H₂O extraction), labile (NaHCO₃ extraction), and moderately labile (NaOH extraction) fractions. In addition, the soil solution cation concentration was one of the most important drivers of available struvite-derived P fractions. The great importance of texture and cations in determining struvite-derived P fractions in soil was contrasted with the relatively minor role of pH. At the microbial level, the number of bacterial operational taxonomic units (OTUs) from the unfertilized soils that correlated with struvite-derived P fractions was higher than that of fungi. The number of OTUs that correlated with the struvite-derived soluble P fraction was dominated by fungi, whereas the number of OTUs that correlated with the struvite-derived labile P fraction was dominated by bacteria. Overall, this study provided a predictive framework for the potential use of struvite as a P fertilizer in contrasting soils.     

Moderately resistant phosphorus forms in subtropical ultisol of Argentina

Abstract

The efficiency of phosphorus (P) fertilization may be improved through knowledge of soil P fraction changes with time. This study examined: i) the distribution of P fractions according to Hedley's fractionation scheme and ii) the sequential changes in soil organic P (OP) and inorganic P (IP) in a typical Kandihumult, under favorable conditions for mineralization and under depletion conditions, with and without P fertilization. Soil P fractions considered were IP‐resin, IP‐ and OP‐bicarbonate, and IP‐ and OP‐hydroxide. The soil is characterized by the predominance of moderately resistant P, in organic and inorganic fractions. In the presence of favorable conditions for mineralization, a substantial decrease in moderately resistant organic P was observed, enhanced even more by fertilizer incorporation. The decrease of total extracted P (TPe) before depletion situations was mainly produced in the moderately resistant fraction, that registered a decrease of 23% (of this value 65% were due to OP). The main fate of the fertilization, in both situations (active mineralization as well as depletion) was moderately resistant inorganic phosphate.     

农作措施对集约化土壤中磷形态变化的影响

Phosphorus (P) in agricultural soils is an important factor for soil quality and environmental protection. Understanding of P and its fractions in soils on a regional scale is imperative for effective management or utilization of P and the improvement of P availability in soils. To study spatial variability and changes of soil P and its fractions as affected by farming practices, soil samples were taken in Rugao County, Jiangsu Province of China, an intensive agricultural area in the Yangtze River Delta region, in years of 1982 (n = 1 514), 1997 (n = 1 651), and 2002 (n = 342). High spatial variabilities of Olsen P and total P (TP) were observed throughout the study area. Loamy Stagnic Anthrosols and clay or loamy Aquic Cambosols had significantly higher concentrations of Olsen P and TP than sandy Ustic Cambosols and Aquic Cambosols. Olsen P and TP were increased from 1982 to 2002. The accumulations of Olsen P and TP in the cultivated soils were likely related to the increased application of P fertilizer, organic input, and soil incorporation of crop residues as well as conversion of soil use. Accumulated soil P was dominantly in labile and semi-labile P fractions. These P fractions may be utilized by future crop production by adjusting management practices, but they also pose a serious threat to nearby water bodies. Future strategies should include decreasing P fertilization in soils and supporting sustainable management. The information from this study can be used to monitor changes in soil fertility and environmental risks so that the use of fertilizers can become more rational.     

杭嘉湖地区水稻土中氟的分布特征

测定分析了杭嘉湖地区400余份水稻土土样中氟（全氟、交换态氟和水溶态氟）的含量，对该地区水稻土中氟的土壤环境质量评价基准值进行了初步研究。结果表明，水稻土中的全氟与可交换态氟含量均呈正态分布。水溶态氟的含量符合对数正态分布。在5种不同母质发育的水稻土中，河相沉积物发育的水稻土全氟含量最高，算术平均值为333．1mgkg^-1；海相沉积物发育的水稻土次之，为324．3mgkg^-1；黄壤和红壤性坡残积物最低，为245．4mgkg^-1。海相沉积物发育的水稻土水溶态氟和可交换态氟含量最高，分别为1．55mgkg^-1和4．03mgkg^-1。不同类型的水稻土（渗育性水稻土、潴育性水稻土、潜育性水稻土和淹育性水稻土）剖面中耕作层的全氟含量均高于亚耕层，而剖面中水溶性氟的分布规律则相反。初步确定杭嘉湖地区水稻土中氟的环境质量评价基准建议值全氟为413．9mgkg^-1，水溶态氟为2．54mgkg^-1。     

外源铜和镍在土壤中的化学形态及其老化研究

采用连续提取法测定了外源铜和镍进入田间土壤后的化学形态分布,比较研究了这2种重金属在3种不同类型土壤(红壤,水稻土和潮土)中随老化时间的形态转化和分布.结果表明,外源铜以残留态(40%～60%)和EDTA可提取态(40%)为主;随老化时间,EDTA可提取态、易还原锰结合态及铁铝氧化态向残留态转化;外源镍在酸性红壤中以可交换态(40%)和残留态(30%～50%)为主,在中性水稻土中以EDTA可提取态(30%)和残留态(30%～50%)为主,在碱性潮土中以铁铝氧化态(20%)和残留态(40%)为主.随老化时间,水溶态、可交换态、EDTA可提取态等向残留态转化.土壤pH较低时水溶态和可交换态含量较高,但是同时随老化时间的降低量也明显;pH较高时有利于易还原锰结合态和有机质结合态的转化.     

Distribution of potassium fractions in sweet potato (Ipomoea batatas) garden soils in the Central Highlands of Papua New Guinea and management implications

Previous studies indicated that potassium (K) deficiency is an important soil‐related factor for yield decline of the sweet potato gardens in the Central Highlands of Papua New Guinea, where sweet potato is an important staple food crop. An effort was made to characterize various fractions of K in the diverse soils of this region under sweet potato, to ascertain the probable reasons behind the observed K deficiency and its relationship to decreasing yield trends. Soils from two depths (0–10 cm) and (10–20 cm) in two types of gardens (old and new gardens) were assessed for different fractions of soil potassium in volcanic and non‐volcanic soil groups. Volcanic soils (Hydrandepts and Andaquepts) were significantly lower (P < 0.05) in exchangeable K than the non‐volcanic soils (Dystropepts, Tropoqualfs and Eutropepts). Mean exchangeable K content of the non‐volcanic soils was 95.5 mg/kg, whereas that of volcanic soils was 72.4 mg/kg. Similarly, new gardens had an average exchangeable K content of 94.1 mg/kg, which was significantly greater than 71.6 mg/kg soil of older gardens. Non‐exchangeable K content differed significantly (P < 0.001) between the soil types; mean K content was 85.9 mg/kg for the volcanic soils, whereas in non‐volcanic soils, it was 184.9 mg/kg. Garden types also differed significantly (P < 0.05) with respect to non‐exchangeable K content; new gardens registering higher average values (by almost 20%) than the older gardens. Multiple regression analysis showed that variability in the tuber yield was as a result of variability of water soluble and exchangeable K (up to 22%), non‐exchangeable K (2%), mineral K (4%) and leaf K concentrations (10%). Older gardens, which are in volcanic soil groupings, are more susceptible to the K depletion problem because of continuous sweet potato cultivation, possibly owing to their lower K reserves. Such gardens should be managed either with sufficient fallow periods for regeneration of soil fertility or with suitable application of mineral K fertilizers to enhance productivity.     

Incorporating Poultry Litter Ash as a Pre-plant Fertilizer to Reduce Nutrient Leaching during Bermudagrass Establishment

ABSTRACT

Pre-plant fertilizers are used to adjust soil fertility for nutrients such as phosphorus (P) during turfgrass establishment. However, nutrient applications of water-soluble sources in coarse-textured soils are prone to leaching compared to slow-release sources. Poultry litter ash (PLA), a by-product of poultry litter combustion, concentrates macronutrients into less water-soluble forms. The objective of this study was to evaluate PLA with triple superphosphate (TSP), in ratios of P in PLA to that in TSP of 0:100, 25:75, 50:50, 75:25; 100:0 as a pre-plant fertilizer incorporated into a 90:10 (v/v) sand and peat mixture seeded with bermudagrass (Cynodon dactylon L.) ‘Sahara’. Bermudagrass groundcover, shoot, and root biomass were measured at 6 weeks. Leachate was captured weekly and analyzed for P, K, Ca, and Mg. Bermudagrass groundcover and biomass accumulation were similar across all treatments at 6 weeks after planting (WAP). The benefit of PLA compared to TSP was the reduction in P, K, Ca, and Mg leached during the first two WAP. As the percentage of PLA increased relative to TSP, nutrient leaching decreased, with 100% PLA resulting in the lowest cumulative nutrient masses leached. Application of 100% PLA as a pre-plant fertilizer can limit nutrient leaching in coarse-textured media compared to more water-soluble nutrient sources, particularly TSP, without delaying bermudagrass establishment.     

中国三种典型耕作土壤的农学土壤测试磷与环境学土壤测试磷的关系研究

A study was conducted to determine the relationships between agronomic soil test P and environmental soil test P in three soils predominately distributing in three typical agricultural production areas of China. Soil P was analyzed using Bray-1 （BP）, Olsen （OP）, and Mehlich-3 （MP） methods as agronomic tests, and using Fe-oxide impregnated filter paper （FeP）, anion-exchange resin membrane （RP）, and water （WP） as environmental tests. There were linear relationships between soil P extractable with all the tests evaluated. The regression coefficients, R^2, ranged from 0.8164 to 0.9409 between each two of the agronomic soil test P, and ranged from 0.4702 to 0.8990 between each two of the environmental soil test P, when the three soils were considered separately. When soil test P was analyzed across all the three soils, the highest regression R^2 was found between OP and MP （0.7940） amongst agronomic soil test P, and between FeP and RP amongst environmental soil test P （0.8842）. While all of the three agronomic soil test P was linearly related to each of the environmental soil test P across the three soils, strongest relationships were found between OP and environmental soil test P. Agronomic OP may be adopted as an analytical tool for environmental prediction of soil P.     

Phosphorus and Potassium Transformations in Soil Amended with Enriched Compost and Chemical Fertilizers in a Wheat–Soybean Cropping System

India imports large amounts of rock phosphate (RP) and potassium (K) fertilizers from other countries; hence, research priorities have been directed toward finding alternative sources of phosphorus (P) and K fertilizers. This study focuses on the transformations of P and K in soil amended with RP and waste mica–enriched compost. The enriched compost had greater total P, K, calcium (Ca), magnesium (Mg), micronutrients, and biological properties than ordinary compost. In a wheat–soybean rotation, application of 5 t ha^?1 enriched compost along with 50% of the recommended rate of inorganic fertilizer resulted in increased concentrations of saloid P, iron (Fe) P, aluminum (Al) P, Ca-P, occluded P, water-soluble K, exchangeable K, and nonexchangeable K over unfertilized plots. In addition, plots that received enriched compost had greater microbial biomass and phosphatase activities than unfertilized plots. Thus, enriched compost could be an alternative source of water-soluble P and K fertilizers for crop production.     

Soil Phosphorus Fractions in a Sandy Typic Hapludaft as Affected by Phosphorus Fertilization and Grapevine Cultivation Period

The purpose of this study was to quantify the phosphorus (P) fractions in phosphate-fertilized sandy soils under grapevines. Soil was sampled from a grassland site and two vineyards (13 and 31 years old) in the State Rio Grande do Sul, Brazil, from the layers 0–5, 5–10, 10–15, 15–20, and 20–40 cm deep. The samples were prepared and P fractions were assessed by chemical fractionation. Phosphate fertilization of the vineyard soils increased P contents to a depth of 40 cm, especially in the more recalcitrant fractions but detectable in the more labile fractions as well, which are plant available and may increase the risk of environmental contamination. Phosphate fertilizers and the period of grapevine cultivation had little effect on the levels of organic P forms, whereas cover crops in vineyards could be an appropriate strategy to increase or maintain the levels of soil organic matter and the levels of organic P over the years.     

Effects of soil flooding on P transformations in soils of the Mesopotamia region,Argentina

In the Mesopotamia region (Argentina), rice is cropped on a wide range of soil types, and the response of rice to fertilizer application has been inconsistent even in soils with very low levels of available phosphorus. Phosphorus transformations in flooded soils depend on soil characteristics that may affect phosphorus availability. This study was conducted to determine which soil characteristics were related to the changes in P fractions during soil flooding. Soils were chosen from ten sites within the Mesopotamia region that are included in five different soil orders: Oxisols, Ultisols, Alfisols, Mollisols, and Vertisols. Soil phosphorus (P) was fractionated by a modified Hedley method before and after a 45 d anaerobic‐incubation period. Changes in the inorganic P extracted with resin depended on soil pH and were related to the exchangeable‐Fe concentration of soils (extracted with EDTA). Inorganic P extracted with alkaline extractants (NaHCO₃ and NaOH) increased due to soil flooding. This increase was related to the organic‐C (OC) percentage of soils (r² = 0.62, p < 0.01), and ranged from 13 to 55 mg kg^–1. Even though previous studies showed that P associated with poorly crystalline Fe played an important role in the P nutrition of flooded rice, in this study, there was no relationship between ammonium oxalate–extractable Fe and P changes in soils due to flooding. Our results suggest that in the Mesopotamia region, changes in P fractions due to soil flooding are related to soil OC, soil pH, and soluble and weakly adsorbed Fe.     

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

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

Corn biomass,uptake and fractionation of soil phosphorus in five soils amended with organic wastes as P fertilizers

Abstract

Sustainable food production includes mitigating environmental pollution and avoiding unnecessary use of non-renewable mineral phosphate resources. Efficient phosphorus (P) utilization from organic wastes is crucial for alternative P sources to be adopted as fertilizers. There must be predictable plant responses in terms of P uptake and plant growth. An 18-week pot experiment was conducted to assess corn (Zea mays L.) plant growth, P uptake, soil test P and P fractionation in response to application of organic P fertilizer versus inorganic P fertilizer in five soils. Fertilizers were applied at a single P rate using: mono-ammonium phosphate, anaerobically digested dairy manure, composted chicken manure, vegetable compost and a no-P control. Five soils used varied in soil texture and pH. Corn biomass and tissue P concentrations were different among P fertilizers in two soils (Warden and Quincy), with greater shoot biomass for composted chicken manure and higher tissue P concentration for MAP. Plant dry biomass ranged from highest to lowest with fertilizer treatment as follows: composted chicken manure?>?AD dairy?=?MAP?=?no-P control?=?vegetable compost. Soil test P was higher in soils with any P fertilizer treatment versus the no-P control. The loosely bound and soluble P (2.7?mg P kg^?1) accounted for the smallest pool of inorganic P fractions, followed by iron bound P (13.7?mg P kg^?1), aluminum bound P (43.4?mg P kg^?1) and reductant soluble P (67.9?mg P kg^?1) while calcium bound P (584.6?mg P kg^?1) represented the largest pool of inorganic P.