Phosphorus and trace metal dynamics in soils amended with poultry litter and granulates

Environmental sustainability of animal agriculture is strongly dependent upon development of approaches to minimize the potential environmental impacts of applying animal manures. The excess manure and its nutrients (primarily phosphorus) in intensive animal production regions may need to be exported to other areas to comply with increased regulations on manure management. In our previous study we generated a variety of granulated products from poultry litter to achieve export of excess litter from the southwestern Ozarks, AR, USA. Our objective in the present study was to determine the effect of the application of poultry litter and granulated litter products on phosphorus (P), arsenic (As), copper (Cu) and zinc (Zn) dynamics in two Arkansas soils (Dewitt silt loam and Hector sandy loam). Poultry litter and granulated products were mixed with the surface horizon (0–15 cm) of soils at two application rates: P‐based (100 kg total P per hectare) and N‐based (160 kg plant‐available N per hectare). Soil–litter mixtures were incubated at 25 °C for 21 days. Sub‐samples were removed at 1, 7 and 21 days to determine the solubility and availability of P, As, Cu and Zn in soils. Results suggest that when litter was applied at 100 kg total P per hectare, contents of P, As, Cu and Zn were significantly greater in the soils amended with litter and granulated products than in the control (soil alone). However, the contents of P, As, Cu and Zn did not significantly differ in the soils amended with either normal litter or granulated litter products at total P or plant‐available N‐based application rates. This suggests that poultry litter granulation is a sound management practice that can be used to reduce concerns with fresh litter transport and potentially improve P and trace element balances in intensive poultry production regions, especially when applied on a plant‐available N basis.     

Nitrogen Mineralization Potential as Influenced by Microbial Biomass,Cotton Residues and Temperature

Integrating information on nitrogen (N) mineralization potentials into a fertilization plan could lead to improved N use efficiency. A controlled incubation mineralization study examined microbial biomass dynamics and N mineralization rates for two soils receiving 56 and 168 kg N ha^?1 in a Panoche clay loam (Typic Haplocambid) and a Wasco sandy loam (Typic Torriorthent), incubated with and without cotton (Gossypium hirsutum L.) residues at 10 and 25°C for 203 days. Microbial biomass activity determined from mineralized carbon dioxide (CO₂) was higher in the sandy loam than in clay loam independent of incubation temperature, cotton residue addition and N treatment. In the absence of added cotton residue, N mineralization rates were higher in the sandy loam. Residue additions increased N immobilization in both soils, but were greater in clay loam. Microbial biomass and mineralization were significantly affected by soil type, residue addition and temperature but not by N level.     

Correlation of solution and extractable phosphorus with vegetative growth of teff

Abstract

Three soils, Hiwassee loam (clayey, kaolinitic, thermic, Typic Rhodudults), Vaiden clay (very fine, montmorillonitic, thermic, Vertic Hapludalfs) and Marvyn sand (fine, loamy, siliceous, thermic, Typic Hapludults), were used in this study. Phosphorus sorption and desorption isotherms of the soils were determined in the laboratory. Average P sorption maximum (b) was calculated using the Langmuir isotherm equation. Based on the P sorption capacity, each soil was fertilized with different P rates and teff [Eragrostis tef (Zucc)] was grown in the greenhouse. The amount of P sorbed and desorbed increased as the concentration of equilibrating solution P increased. Phosphorus sorption maximum from sorption and desorption isotherms was 278, 251, and 37 mg P/kg for Hiwassee, Vaiden, and Marvyn soils, respectively, and for maximum dry matter yield of teff the soils needed a minimum of 0.029, 0.048, and 0.065 mg/L soil solution P, respectively, which were all below the soil solution P at P adsorption maximum.

Soil P was extracted by the Mehlich I, Mehlich III, modified Mississippi, Bray P‐l and Olsen methods. Plant‐available P extracted by each of the five methods was significantly correlated with teff dry matter yield, and statistically any of the five methods can be used as the basis for predicting teff yield responses.     

Toxicity of brass powder to corn and the relationship to soil fractionation of copper and zinc

Abstract

The relationship of Cu and Zn fractionation in soils to plant growth was investigated on a Sassafras sandy loam (fine‐loamy, siliceous, mesic Typic Hapludult) and a Joppa gravelly sandy loam (loamy‐skeletal, siliceous, mesic Typic Hapludult). Pot studies were conducted in the greenhouse exposing corn (Zea mays cv. Silver Queen) to concentrations of 0, 100, 200, and 400 mg brass powder/kg soil. The corn was grown over a two week period, during which time individual plant heights were taken to note differences in plant growth. Data showed that plant height was reduced when the concentration of brass powder in the soil was increased. Total and fractionated Cu and Zn levels in the soils were analyzed and compared to height. Regression equations showed a more explicit relationship between height and exchangeable Cu levels rather than other Cu and Zn levels in the two soils. Additionally, a more pronounced effect was seen in plants grown on the Sassafras sandy loam, which was attributed to differences in soil physicochemical properties.     

Correlation of Soil pH and Mehlich‐3 Phosphorus with Postflood Rice Phosphorus Concentrations in Arkansas

Abstract

Plant‐available phosphorus (P) measured by routine soil‐test methods is poorly correlated with rice grain yield in Arkansas. Our objective was to determine whether soil water pH (pH_w) and Mehlich‐3 P were correlated with growth and yield of rice grown on silt loam soils. Data from 35 field studies were used to correlate Mehlich‐3 P and pH_w with relative yield, dry matter accumulation, and P concentration at the midtillering stage. Significant linear or nonlinear relationships between pH_w or Mehlich‐3 P with rice growth parameters were delineated but explained less than 27% of the variability in dry matter and P concentrations at the midtillering stage and grain yield at maturity. Mehlich‐3 P and pH_w together explained 61% of the variability in midtillering P concentrations. Midtillering whole‐plant P concentrations were positively related to relative grain yield and dry matter production and will be used to identify soils with limited P availability for rice in Arkansas.     

Phosphorus deficiency diagnosis and fertilization in mungbean grown in rainfed calcareous soils of Pakistan

Abstract

Mungbean [Vigna radiata (L). Wilczek] grown in rainfed calcareous soils suffers with phosphorus (P) deficiency. In view of high cost and low use efficiency of P fertilizer, greenhouse, incubation, and field experiments were carried out for determining P deficiency diagnostic criteria and efficient method of P fertilizer application in mungbean. In a pot culture experiment using a P‐deficient Typic Ustocherpt, maximum increase in grain yield with P was 686% over the control; and fertilizer requirement for near‐maximum (95%) grain yield was 30 mg P kg^‐1 soil where fertilizer was mixed with the whole soil volume (broadcast) and 14 mg P kg^‐1 where mixed with 1/4th soil volume (band placement). In a field experiment on a P‐deficient Typic Camborthid, however, maximum increase in grain yield was 262% over the control. Band placement resulted in 73% fertilizer saving as P requirement was 66 kg ha^‐1 by broadcast and only 18 kg ha^‐1 by band placement. Critical P concentration range appears to be 0.27–0.33% in young whole shoots (≤30 cm tall) and 0.25–0.30% in recently matured leaves. In an incubation study using the same Typic Ustochrept, P extracted by the sodium bicarbonate (NaHCO₃), the ammonium bicarbonate‐diethlylenetriaminepentaacetic acid (AB)‐DTPA), and the Mehlich 3 soil tests correlated closely with each other, P concentration of whole shoots, and total P uptake by mungbean plants. Critical soil test P levels for pot grown mungbean were NaHCO₃,9 mg kg^‐1; AB‐DTPA, 7 mg kg^‐1; and Mehlich 3, 23 mg dm^‐3 soil. The more efficient and economical ‘universal’ soil test, AB‐DTPA, is recommended for P fertility evaluation of calcareous soils.     

Determining differential water movement through ion exchange resin for nitrate leaching measurements

Abstract

The fate of fertilizer N applied to agricultural soils is of growing concern due to the potential for groundwater contamination. The recent development of an exchange resin that specifically absorbs NO₃ has led to the potential for a new technique to measure cumulative NO₃ leaching. The main limitation to the application of the resin technique is the matching of water movement through the resin with that of soil. A soil water movement device was developed to compare water movement through the resin to that of soil. A study was initiated to develop a resin/soil pack with water movement characteristics that closely matches those of natural soils. Three different soil types were used in this study: a Cahaba sandy loam (fine‐loamy, siliceous, thermic Typic Hapludult), a Congaree clay loam (fine loamy, mixed, nonacid, thermic Typic Udifluvent), and a Hiwassee clay (clayey, kaolinitic, thermic Typic Rhodudult). Both pure resin and resin mixed with soil were found to have higher water movement characteristics compared to bulk soil. A resin pack method was found which had water movement characteristics that were not significantly different from that of bulk soil for the three different soil types. The resin pack method is described.     

Predicting the degree of phosphorus saturation using the ammonium acetate–EDTA soil test

As a result of the important role played by phosphorus (P) in surface water eutrophication, the susceptibility of soils to release P requires evaluation. The degree of phosphorus saturation, assessed by oxalate extraction (DPS_ox), has been used as an indicator. However, most laboratories do not include DPS_ox in routine soil tests because of cost and time. This study evaluates the suitability of the ammonium acetate extraction in the presence of EDTA (AAEDTA), the standard soil test P (STP) in Wallonia (Southern Belgium), to predict DPS_ox; we also compared it with the Mehlich 3 extraction. Ninety‐three topsoil samples were collected in agricultural soils throughout Wallonia. Good correlations were found between the AAEDTA and the Mehlich 3 methods for P, Fe and Al (r = 0.85, 0.77 and 0.86, respectively). An exponential relationship was found between P_AAEDTA and DPS_ox. Results of principal component analysis and regression demonstrated that STP can be used to predict DPS_ox (r = 0.93) after logarithmic transformation. Soil test Al was also a good indicator of the P sorption capacity (PSC_ox) of soils (r = 0.86). Including the clay fraction in regression equations only slightly improved the prediction of PSC_ox (r = 0.90), while other readily available data (such as pH or organic carbon) did not significantly improve either DPS_ox or PSC_ox predictions.     

Relation between soil P test values and mobilization of dissolved and particulate P from the plough layer of typical Danish soils from a long‐term field experiment with applied P fertilizers

Accumulation of phosphorus (P) in agricultural topsoils can contribute to leaching of P which may cause eutrophication of surface waters. An understanding of P mobilization processes in the plough layer is needed to improve agricultural management strategies. We compare leaching of total dissolved and particulate P through the plough layer of a typical Danish sandy loam soil subjected to three different P fertilizer regimes in a long‐term field experiment established in 1975. The leaching experiment used intact soil columns (20 cm diameter, 20 cm high) during unsaturated conditions. The three soils had small to moderate labile P contents, expressed by water‐extractable P (3.6–10.7 mg/kg), Olsen P (11–28 mg/kg) and degree of P saturation (DPS) (25–34%). Mobilization of total dissolved P (TDP) increased significantly (P < 0.05) from the intact soil columns with increasing labile P, whereas the increase in particulate P (PP) with increasing labile P content was modest and statistically insignificant. We found concentrations up to 1.5 mg TP/L for the plough layer of this typical Danish sandy loam soil. This highlights that even a moderate labile P content can be a potential source of TDP from the plough layer, and that a lower concentration margin of optimum agronomic P levels should be considered.     

Investigation of acid hydrolysis reactions of polyphosphates and phytic acid in Bray and Mehlich III extracting solutions

Soil test phosphorus (STP) (Bray P-1, Mehlich III) was developed to predict the plant available P in agricultural soils in the USA. The acidic STP extracting solutions were intended to extract phosphate from alkaline earth metal-based solubility products and or adsorbed species on amorphous metal hydroxides or phyllosilicates in soils. However, the accuracy of STP in predicting plant available phosphate has often been questioned due to potential acid hydrolysis of poly- and organic-P in soils during the STP extraction. The objective of the study was to investigate the acid hydrolysis reaction of reference poly- and organic-P compounds (1.25–3.75 mM) in Bray and Mehlich III extraction solutions using spectrophotometric methods. The results showed that both tripolyphosphate and pyrophosphate readily underwent the acid hydrolysis reaction over 2 h, whereas phytic acid did not hydrolyze. The results suggest an overestimation of dissolved reactive phosphate from these polyphosphates should be considered when evaluating the STP data.     

土壤质地对柱花草生长发育、生物量及土壤肥力变化的影响

采用大田试验的方法,在云南省元谋县小雷宰流域内壤土、砂壤土和重壤土3种质地土壤上,以热研5号柱花草为材料,研究土壤质地对柱花草生长发育、生物量及土壤有机质、有机碳、全氮和全磷的影响。试验结果表明:3种土壤质地上种植柱花草,柱花草地上部和地下部生长量和生物量表现幼苗期增加缓慢,而分枝期后增加快的趋势。壤土耕性好,兼有砂土和重壤土的优点,有利柱花草地上部分的生长发育,柱花草地上部生长量、生物量及改善土壤肥力方面显著高于重壤土。砂壤土有利于柱花草根系向深层土壤生长,柱花草地下部生长量、生物量及根瘤显著高于种植在重壤土。在3种土壤质地种植柱花草后,土壤有机质、有机碳、全氮和全磷均有上升趋势。综合而言,通气性和保肥保水能力居中的壤土更适合柱花草的生长发育及干物质的积累。     

Evaluation of Mehlich 3 extractant for estimating phosphorus deficiency and phosphorus sorption of Zimbabwean soils

Abstract

The Mehlich 3 extractant was compared with the resin method for its ability to predict the phosphorus (P) status of Zimbabwean soils. Correlation of P extraction between the two methods and with plant growth was found to vary with soil texture. Because the Mehlich 3 extractant was less influenced by texture, it was better able to predict the P status over a wide range of soil types. The Mehlich 3 extractant correctly predicted P deficiency for all Zimbabwean soils, except for those that contained visible calcium carbonate. Mehlich 3‐extractable aluminum (Al) was very highly correlated with the maximum P‐sorption capacity of a wide range of soils, excluding those with calcium carbonate. Adoption of the Mehlich 3 extractant for multiple elemental analysis of soils in Zimbabwe is recommended, particularly if routine Al measurement is included as an indicator of soil P requirements.     

Differential leaching of cations and sulfate in gypsum amended soils

Abstract

An adequate supply of available Ca in the soil solution of the pegging zone during fruit development is required for production of high yields of high quality peanuts (Arachis hypogaea L.). On low Ca soils, application of gypsum during early bloom is recommended in order to ascertain adequate availability of Ca. Reaction of gypsum in soils under leaching conditions vary considerably and play an important role in fruit development and yield of peanuts. A laboratory study was conducted in leaching soil columns to investigate the effects of one gypsum amendment on leaching of Ca, K, Mg, and SO₄ to a depth of 8 cm (fruiting zone of peanut). Six soils of varying physical and chemical properties representative of major peanut growing soils in Georgia were utilized. Following leaching with 15 cm water through gypsum‐amended soil columns, 50% to 56% and 74% to 77% of applied Ca and SO₄, respectively, were leached below 8 cm in the sandy‐Carnegie, Dothan, Fuquay and Tifton soils. The respective values for the sandy clay loam‐Greenville and Faceville soils were 28% to 36% and 58% to 69%. Lower initial Ca status and greater leaching of Ca from the applied gypsum in the sandy soils as compared to sandy clay loam soils suggest greater beneficial effects of supplemental gypsum application for peanut production in the former soils than in the latter soils. Leaching of K or Mg (as percentage of Mehlich 1 extractable K or Mg) in gypsum‐amended treatment was considerably greater in sandy soils than that in the sandy clay loam soils. In view of the reported adverse effects of high concentrations of soil K and Mg in the fruiting zone on the yield and quality of peanuts, greater leaching of K and Mg from the fruiting zone in gypsum amended sandy soils enable them to maintain a favorable cation balance for the production of high yields of quality peanuts.     

Phosphorus sorption,supply potential and availability in soils with contrasting parent material and soil chemical properties

Soil phosphorus (P) management requires a more targeted and soil‐specific approach than is currently applied for agronomic recommendations and environmental evaluation. Phosphorus buffering capacities control the supply of P in the soil solution and were measured across Irish soils with contrasting parent material and chemical properties. Langmuir sorption buffer capacities (MBCs) and binding energies (b) were strongly correlated with soil pH and extractable aluminium (Al). A broken‐line regression fitted to the relationship between MBC and Al derived a change‐point value for Al above which MBC increased linearly. Soils above the change point were predominantly acidic to neutral with non‐calcareous parent material, with larger buffering capacities and binding energies than calcareous soils. Ratios of Mehlich3‐Al and P (Al:P) were used to relate buffering capacity to supply potential in non‐calcareous soils. Large ratios of Al:P were associated with poor P availability, characteristic of strongly P‐fixing soils. Threshold values of iron‐oxide paper strip P (FeO‐P) and Morgan's P revealed Al:P ratios where soils began to supply P in available form. The change‐point for Morgan's P fell within the current target index for P availability; however, the confidence interval was more compatible with previous agronomic P indices used in Ireland. Relationships between Morgan's P and measures of extractable P, M3‐P and Olsen P, deviated in calcareous soils at large soil P contents, indicative of P precipitation processes dominating in these soils. Identifying differences in soil P buffering capacity at the laboratory scale would improve agronomic and environmental assessment at field and catchment scales.     

Extraction Methods for Phosphorus and Their Relationship with Soils Phosphorus‐Buffer Capacity Estimated by the Remaining‐Phosphorus Methodology‐A Pot Study with Maize

Abstract

This work aimed to calibrate Mehlich 1, Mehlich 3, Bray 1, Olsen, and ion‐exchange resin extraction methods with maize phosphorus (P) responses in a pot study with lowland and upland soils with different P‐buffer capacities and to evaluate whether the calibration can be enhanced through the knowledge of remaining P. The experimental design was completely randomized with four replications in a factorial arrangement involving five P concentrations and four lowland or seven upland soils. The remaining P for each soil was determined, P‐buffer capacity was estimated, and the soils were grouped according to the results. Correlation coefficients showed that the remaining P is strongly dependent on clay and soil organic‐matter content, and its determination was useful to the evaluation of the extractants. The classification and grouping of soils according to their P‐buffer capacity improved the correlations between extracted P and plant response for Mehlich 1 and Bray 1 extractants. The Mehlich 3, Olsen, and resin methods presented better performances, independent of soil grouping.     

山西省菜园土壤磷素积累特征及流失风险分析

为了解山西省不同区域菜园土壤磷素积累以及流失情况, 本文分析了菜园土壤磷饱和度(DPS)、Mehlich3-P、Olsen-P与水溶性磷(Pw)的积累特征.结果表明: 山西各地菜园土壤4种磷素(土壤全磷、水溶性磷、Olsen-P和 Mehlich3-P)积累明显, 已经远远超过作物需求量; 土壤表层水溶性磷含量随着土壤磷饱和度(DPS)、Olsen-P、Mehlich3-P含量的增加而增加; 且Mehlich3-P与Olsen-P、水溶性磷与Olsen-P、水溶性磷与Mehlich3-P之间具有极显著相关性, 相关系数分别为0.976 6、0.923 2、0.962 0 (P<0.01); 当磷饱和度大于46.64%、Olsen-P大于81.88 mg·kg-1、Mehlich3-P大于164.59 mg·kg-1时, 水溶性磷含量上升幅度迅速增大, 由此将土壤磷饱和度为46.64%、Olsen-P 为81.88 mg·kg-1、Mehlich3-P为164.59 mg·kg-1和水溶性磷为8.05 mg·kg-1初步确定为山西省菜园土壤磷素流失的临界值.该结果将为探讨山西农田土壤磷素的养分管理和环境风险评估提供重要的理论依据.     

Comparisons of phosphorus availability between anion exchange resin and mehlich‐1 extractions among Oxisols with different capacity factors

Abstract

Acid and dilute‐salt chemical extractants are commonly used to assess and adjust phosphorus (P) availability in soils. Soybean was grown for 45 days under greenhouse conditions on samples of 10 Oxisols treated with variable levels of soluble P to compare critical soil P levels between an anion exchange resin (AER) and the Mehlich‐1 extractant, and to evaluate the influence of the soil P capacity factor (PCF) on the critical soil P levels. Variation among soils in the quantities of extracted P and critical P levels with the AER was less than that with Mehlich‐1. Low correlation values between soil characteristics related to PCF and measurements of AER soil P suggested that the AER method was not as sensitive to variations in soil PCF as Mehlich‐1. Interpretations of AER critical P levels, therefore, do not need auxiliary measures of PCF as with the Mehlich‐1 extractant. The reverse was true, however, for P uptake. Therefore, the criteria used to assess plant response to P (P uptake or dry matter production) in soils with variable PCF will influence the results obtained in correlations between methods used to extract soil P.     

互花米草入侵对滨海湿地不同质地土壤碳氮磷及其生态化学计量比的影响

为了阐明外来物种入侵对滨海湿地不同质地土壤碳(C)、氮(N)、磷(P)及其生态化学计量比的影响，对福建省滨海地区东湖湿地两种质地土壤的土著种与入侵种植被下土壤C、N、P含量及其生态化学计量特征与影响因素进行了测定与分析。研究结果表明：相同植被下，壤质土的C、N、P及其计量比均高于砂质土。互花米草入侵增加了两种质地土壤的C、N含量及碳磷比(C/P)、氮磷比(N/P)，降低了土壤有效磷(AP)、P含量与碳氮比(C/N)，其中砂质土的土壤N含量显著增加了近1倍(P<0.05),AP含量下降近70%，壤质土的C/P增加了近2倍(P<0.05)。不同质地土壤中铵态氮(NH₄⁺-N)和硝态氮(NO₃^–-N)含量对互花米草入侵的响应不同，在壤质土中，互花米草入侵后降低了50%的NH₄⁺-N含量，增加了近3倍的NO₃^–-N含量(P<0.05)；而在砂质土中，互花米草入侵后土壤NH₄     

Impact of Soil Water Content and Core Sampler Diameter at Sampling for Dry Soil Fragment‐Size Distributions

Soil conditions at sampling and the dimensions of the sample are critical factors when soil aggregation is indirectly characterized by determining the distribution of soil fragments. Our objective was to determine the effects of gravimetric soil water content and core sampler diameter (16, 54, and 84 mm) at sampling on the dry‐fragment‐size distribution of two soils (Typic Paleudalf and Typic Hapludalf) under undisturbed Festuca arundinacea L. sod and recently rototilled treatments. The 16‐mm core diameter sampler compressed the rototilled soil, and it was not appropriate for soil aggregation studies. The fragmentation of samples taken with core diameters greater than 54 mm decreased with decreasing soil water content. A greater probability of discriminating between undisturbed and fragmented silt loam or clay loam soils was observed when sampling with a 54‐mm‐diameter probe and when the soil had a mean soil water content of 237g kg^?1 or at a potential of ?0.61MPa.     

Impact of Experimental Factors in Soil Phosphorus Tests: Shaking Vessel,Filtration, and Centrifugation

In the analysis of Mehlich III, deionized water (DI), Bray, and Olsen soil phosphorus (P) extractions, variations in shaking vessel, centrifugation, and filter paper result in different soil test P (STP) values. Of these factors, centrifugation and type of filtration were found to have the greatest impact on the results of water‐extractable P (WEP), that is, extraction with DI. Further spectrophotometric experiments demonstrated that centrifugation removed fine soil particles from the extract. Without the commonly used 0.45‐µm filters or centrifugation, these particles scatter the radiation of the spectrometer. During colorimetric analysis, this scattering of radiation will be perceived as absorption. This misperception results in a falsely high STP. In WEP analysis with only qualitative filtration, the scattering is very significant and appears to be due to limited aggregation of soil particles in the low ionic strength extract.