Doses Of Pig Slurry Research Articles

Soil, water and p losses by water erosion in soil treated with pig slurry

Pig slurry (PS) can modify the soil fertility and influence the water erosion. The aim of this research was to evaluate the effect of PS doses on the content phosphorus (P) in the soil and on water (WL) and P losses due to water erosion, in a Alfisol in southern Brazil. The treatments, totaling 0, 250, 500, and 1000 m3 ha-1 of PS applied in oats (Avena strigosa), corn (Zea mays), turnip (Raphanus sativus L.) and soybean (Glycine max), and in oat residues. Simulated rainfall (65 mm h-1 and 75 minutes) was applied three times (test -T) on corn and four T on turnip, soybean, and residues, with a simulator rotating-boom. T1 occurred one day after the application of the PS and the interval between the other T ranged from 14 to 70 days. The P in the soil was determined before and after the survey. During runoff, runoff samples were collected to determine WL and P in the water. The PS did not influence the P in the soil. The P in runoff water was 78% higher in the D1000 treatment than in D0, while the difference in total P loss was 90%. Soil P at the end of the research increased at the beginning of the research, and the content in the soil at the end of the research decreased with increasing layer depth. P loss increased with increasing water loss, while P in water increased with increasing P in the soil.

Micromorphology of pores and water erosion in Inceptisol soil after application of pig slurry

The application of pig slurry (PS) to soil is known to change its chemical and physical properties. However, little is known about the alterations that PS causes in pore morphology and water erosion. This research evaluated the influence of PS on the morphology of the pores in the surface layer of the soil and on water erosion in an Inceptisol subjected to simulated rainfall. The soil was cultivated with black oats and the treatments (doses) 0, 50, 100 and 200 m3 ha-1 of PS were applied to the crop residue. The experimental design was completely randomized. Six simulated rainfall lasting 60 minutes and planned constant intensity of 65 mm h-1 were applied to the treatments. Undisturbed soil samples were collected in the 0-0.05 m layer, 24 h before and 24 h after the first, third and sixth rainfall events. Image analysis was performed, determining the percentage of macropores and mesopores, number, diameter and shape of the pores, using the micro morphometry technique. PS doses of 100 and 200 m3 ha-1, combined with simulated rainfall, favored surface sealing and pore rearrangement. There was an increase in the number of small and rounded pores, without interconnection between them, with a consequent increase in water erosion until the moment of stabilization of the superficial crust.
 Keywords: micro morphometry, organic fertilizer, porometry.

Changes in Dry Matter and Carbon, Nitrogen, and Sulfur Stocks after Applications of Increasing Doses of Pig Slurry to Soils with Tifton-85 for Six Years in Southern Brazil

Pig slurry (PS) has been used as soil fertilizer due to its nutrient and organic matter contents, which may improve soil nitrogen, carbon, and sulfur stocks. The objective of this work was to evaluate the best PS dose that favors the increase in dry matter production and carbon (C), nitrogen (N), and sulfur (S) contents and stocks after applications of PS to soils with Tifton-85 for six years. The experiment was conducted in a randomized block design with four replications, in a hay-producing area under a clayey Typic Hapludox in southern Brazil. The treatments consisted of annual applications of organic and mineral fertilizers at rates based on their N contents, using PS (100, 200, 300, and 400 kg ha−1) and urea (200 kg ha−1), and a control without N application. Samples of the soil in 0–5, 5–10, and 10–30 cm layers were collected in March 2019 and evaluated for soil bulk density and N, C, and S contents and stocks. The Tifton-85 dry matter production was evaluated using samples from three cuts carried out between 2012/2013 and 2017/2018 agricultural years. The applications of increasing doses of PS in Tifton-85 pastures over six years increase linearly the dry matter and soil organic C, N, and S stocks in the 0–30 cm layer. The PS rate equivalent to 100 or 200 kg ha−1 of N is recommended for increasing soil C, N, and S stocks, since it resulted in C, N, and S stocks equal to or higher than the control and mineral (urea) treatments.

Seven years of pig slurry fertilization: impacts on soil chemical properties and the element content of winter barley plants

Intensive pig farming produces large amounts of slurry, which is applied to agricultural soils as fertilizer. A 7-year field study was performed to check the effect of pig slurry on soil properties and on the accumulation of some essential nutrients and heavy metals in a calcareous silty-loam soil (0–0.3 m) and in barley (Hordeum vulgare L.) plants in two cropping seasons with contrasting amounts of rainfall. Five fertilization treatments, control (no N applied), mineral fertilizer (90 kg N ha−1), and different N doses of pig slurry (146, 281, 534 kg N ha−1), were applied at sowing of a barley crop. Organic carbon, available P and K, and total P in soil increased with slurry dose. No differences were found in Co, Cr, Fe, Mn, Ni, and Pb soil concentrations. Slurries increased Cu, Mn, and Zn extractions and plant concentrations of P in straw and Zn in grain. However, the lowest slurry rate was able to maintain the highest grain yields while improving fertility. The results of this research study support the sustainability of pig slurry fertilization at appropriate rates in relation to soil chemical quality.

Effect of high pig slurry doses on yields and ionic balance of white mustard

Effect of high pig slurry doses on yields and ionic balance of white mustard

Modifications of soil organic matter structure by long-term pig slurry amendment of tropical soil

ABSTRACT This work aimed to study the impacts of long-term pig slurry (PS) amendment by soil organic matter (SOM) structural characterization. The study was conducted over 5 years in an experimental field with PS amendment. Two doses (50 m3 ha−1 and 100 m3 ha−1) of PS were applied to soil twice every year, once before planting the winter crop (Avena strigosa Schreb. + Lolium multiflorum Lam.) and once before planting the summer crop (Zea mays L.). SOM modifications were studied by compositional and spectroscopic analyses. Differences between the fractions were obtained using chemometrics methods. PS amendment of the soil caused increases in the amount of total soil carbon and the humic fraction depending on the duration of PS amendment. Humic acids (HAs) and fulvic acids (FAs) functional groups were modified under both rates of PS amendment. The PS amendment modified the HAs and FAs structure in the first year, and in the last year, the higher application rate (100 m3 ha−1) caused more intense modifications than in earlier years. The cluster and MCR analysis proved that carbohydrate and peptide structures (CAlkyl-O,N; CAlkyl-O; CAlkyl-di-O), lignin (CArom-H,R; CArom-O,N) and lignocellulosic carbon were incorporated into the soil HAs and FAs structures.

Monitoring of physicochemical parameters of soils after applying pig slurry. Analysis of its application in short and long periods in the province of Córdoba, Argentina

Soil amendment with manures from intensive livestock breeding is, currently, a usual practice which could produce positive and/or negative effect on several soil properties. In this work, the effect of consecutive additions of pig slurry (PS), during 1 and 15 years, in two different farms in the Province of Córdoba (Argentina), was analyzed. Also, a control soil (without amendment), and an untilled soil were studied for comparison for each farm. This is the first research to be conducted in this part of the country. In this research we study the effect of PS applications in large commercial pig farms. For all soils and PS samples collected the following parameters: pH, electrical conductivity (EC), total N (TN), available phosphorus (P), Na, K, Ca and Mg, were analyzed. PS presents an alkaline pH, high EC, high phosphorus and nitrogen content. The statistical analysis, shown that PS application for 15 years could significantly modify the soil physicochemical properties, but one PS application before harvest, is similar to soil control. The soil amended with PS through 15 years shown: higher pH (7.57), and EC (3.09 dSm−1) values, and high P content (264 ppm), probably due to the low P mobility. Values of TN (2.15 g L−1) increased with the PS application, making this. The PS application, as a soil amendment, an advantage treatment for TN conservation and to avoid the commercial fertilizer use. PS application has to be planned in order to increase the soil nutrient recovery. The PS doses (m3 ha−1) must be carefully calculated to prevent soil nutrient unbalance and possible soil and/or groundwater contamination. These results could be an important contribution on the proper PS application, as soil amendment, in the province of Córdoba and in other Argentinian regions.

Phosphorus forms leached in a sandy Typic Hapludalf soil under no-tillage with successive pig slurry applications

Successive pig slurry (PS) applications can substantially increase phosphorus (P) movement due to leaching, mainly in sandy soils found in areas presenting high rainfall rates. The aim of the current study was to assess the transference of different P forms through leachate in a soil managed under no-tillage system, in a crop rotation system subjected to successive PS applications. The study was carried out from 2005 to 2007; the studied site presents Typic Hapludalf soil and its mean annual rainfall reaches 1,769 mm. The study adopted PS doses 0, 20, 40 and 80 m3 ha-1, which were applied to soil surface before each crop-sowing process. Leachate samples were collected 0.60 m down in the ground at each rainfall event (n = 24) that resulted in solution leaching during the experimental period. Available-P, soluble-P, particulate-P and total-P concentration in the leachate were determined. Successive PS applications increased leachate and P transfers in the leached solution. Phosphorus was transferred via leaching mainly in the particulate form, but soluble-P concentration increase was also observed. The highest P concentrations were observed in the treatment with the highest PS dose, whereas the highest P amounts were transferred in the treatment 40 m3 ha-1 of PS. The total amount of transferred P was very small – 0.2 kg ha-1 year-1 –, but it evidenced the likelihood of groundwater contamination, mainly due to increase in the available-P proportion. In addition, P concentrations in the leachate indicate that high and frequent PS doses should be avoided in sandy soils.

Maize yield after long-term application of pig slurry

ABSTRACT Organic wastes produced in large quantities in pig farms, such as liquid swine manure (LSM), can become a good alternative source of nutrients for agriculture, thus enabling total or partial replacement of mineral fertilizers in agricultural crops. The aim of this study was to evaluate the use of LSM as a substitute of mineral fertilizer in the maize crop under Cerrado soil conditions. The treatments consisted of using mineral fertilization recommended for the maize crop; without fertilization; and LSM doses (25, 50,100 and 200 m3 ha-1). Maize grain yield was evaluated in the 2004/2005, 2005/2006, 2006/2007, 2007/2008, 2009/2010, 2011/2012 and 2013/2014 crop seasons. The mineral fertilization in maize can be replaced by pig slurry doses from 100 m3 ha-1 in a Cerrado soil (dystroferric Red Latosol with clayey texture) with no loss of yield components.

Modeling Zinc and Copper Movement in an Oxisol under Long‐Term Pig Slurry Amendments

Core Ideas Eleven years of Zn and Cu movement in an Oxisol amended with pig slurry (PS) was modeled. Root growth and water uptake effects were successfully added in HYDRUS simulations. Concentration profiles of Zn were described better than those of Cu. DOC‐facilitated Cu transport needs to be considered when modeling Cu transport in soils. Zn concentrations will not be a problem during the next 50 yr in PS‐amended soils. Increases in Zn and Cu concentrations in soils amended with pig slurry (PS) can be described using numerical models. Our main objective was to validate that the HYDRUS‐1D model is able to numerically describe profile concentrations and long‐term vertical transport of Zn and Cu in a clay soil (Oxisol) cultivated under annual cropping in a no‐till system and contaminated by successive doses of PS amendments. We first used a modeling approach that had previously been validated for an Alfisol. Then, we additionally also evaluated the effects of root growth and root water uptake on the transport of trace metals (TMs). Finally, we carried out 50‐yr‐long prospective simulations for different doses of PS amendments. Consideration of root growth and root water uptake processes in HYDRUS‐1D simulations improved the description of measured field Zn concentrations. Although the correspondence between simulated and measured Cu concentrations was not as good as for Zn, we performed prospective simulations for both elements. Future scenarios that considered large PS doses showed large increases in concentrations of both TMs in the soil surface layer. The feasibility of using PS amendments on agricultural Oxisols will be limited by Cu because the soil Cu threshold concentration is exceeded in approximately 29 yr. Moreover, the total loads of both TMs allowed on agricultural soils are reached very fast when large rates are used, especially for Cu (19 yr), indicating that the long‐term disposal of PS on agricultural soils should be done at low doses. These conclusions are probably conservative because our model did not consider potential leaching of TMs from the surface soil into deeper soil layers by dissolved organic C facilitated transport.

How does pig slurry fertilization influence percolated water and runoff erosion? A study of the soybean cycle in Brazilian Cerrado soil

The objective of this study was to evaluate the effects of pig slurry (PS) and chemical fertilizer (NPK 02–20–20) applications on soil water infiltration; sediment, water and nutrient losses by runoff; and soybean yield during a soybean (Glycine max L.) cropping cycle. A field study was carried out in Rio Verde, Goiás, Brazil on a Cerrado Oxisol managed with no tillage. The experiment was arranged as a randomized block design with three replications and treatments. The treatments consisted of two doses of PS, 25 and 100m3ha−1, and chemical fertilization at 370kg ha−1 (NPK 02–20–20) applied to the soil surface in a single application. After the occurrence of rainfall events, the volume of percolated water in lysimeters and the sediment and water losses in plots was measured. To determine the macro and- (Ca, Mg, K, P) micronutrients (Fe, Mn, Cu, Zn), runoff water was collected. We also assessed the dry biomass and productivity of soybean production at the end of the experiment. Treatment with 25m3ha−1 of PS resulted in higher amounts of (106mm) percolated water in the soil (p>0.05). Neither losses of water, sediment and nutrients or biomass production and soybean productivity were significantly affected by the PS treatments compared with chemical (NPK) fertilization (p>0.05). A trend of higher sediment and water losses was observed in the 25m3ha−1 PS treatment (249.86kg ha−1 and 20.58mm, respectively) compared with the 100m3ha−1 PS and chemical (NPK) treatments; the 25m3ha−1 PS treatment showed ~10% and ~43% higher values of sediment losses, respectively, and ~43% and ~23% higher values of water losses, respectively. Regarding soybean productivity, the 25m3ha−1 PS treatment showed a tendency of low productivity (3405kg ha−1) that was ~15% and ~20% lower than that of the 100m3ha−1 PS and chemical (NPK) treatments, respectively. The low values of sediment and water required per kilogram of soybean produced in the chemical fertilization and 100m3ha−1 PS treatments indicate that these management regimes are more sustainable.

Effect of fertilising with pig slurry and chicken manure on GHG emissions from Mediterranean paddies

Soil fertilisation affects greenhouse gas emissions. The objective of this study was to compare the effect of different fertilisation strategies on N2O, CH4 emissions and on ecosystem respiration (CO2 emissions), during different periods of rice cultivation (rice crop, postharvest period, and seedling) under Mediterranean climate. Emissions were quantified weekly by the photoacoustic technique at two sites. At Site 1 (2011 and 2012), background treatments were 2 doses of chicken manure (CM): 90 and 170kgNH4+-Nha−1 (CM-90, CM-170), urea (U, 150kgNha−1) and no-N (control). Fifty kilogram N ha−1 ammonium sulphate (AS) were topdress applied to all of them. At Site 2 (2012), background treatments were 2 doses of pig slurry (PS): 91 and 152kgNH4+-Nha−1 (PS-91, PS-152) and ammonium sulphate (AS) at 120kgNH4+-Nha−1 and no-N (control). Sixty kilogram NH4+-Nha−1 as AS were topdress applied to AS and PS-91. During seedling, global warming potential (GWP) was ~3.5–17% of that of the whole rice crop for the CM treatments. The postharvest period was a net sink for CH4, and CO2 emissions only increased for the CM-170 treatment (up to 2MgCO2ha−1). The GWP of the entire rice crop reached 17Mg CO2-eqha−1 for U, and was 14 for CM-170, and 37 for CM-90. The application of PS at agronomic doses (~170kgNha−1) allowed high yields (~7.4Mgha−1), the control of GWP (~6.5MgCO2-eqha−1), and a 13% reduction in greenhouse gas intensity (GHGI) to 0.89kgCO2-eqkg−1 when compared to AS (1.02kgCO2-eqkg−1).

Crop yield and nutrient balance influenced by shoot biomass management and pig slurry application

ABSTRACT Crop systems that export large amounts of nutrients from the farm may require higher doses of animal manure than those needed for grain production. This study aimed to evaluate the yield of crops and to determine the simplified nutrient balance in three management systems of shoot biomass of crops (cover-grain, cover-silage and hay-silage) associated with five fertilization treatments (control, soluble fertilizer and three doses of pig slurry). The experimental design was a split plot, arranged in randomized blocks with four replicates. The management systems of shoot biomass did not affect the yield of the winter pasture, but there was an increase in yield with the application of pig slurry. The summer crops responded differently to fertilization, depending on the purpose for which they were grown, whether for grain or silage. In the three management systems of shoot biomass, there was an excess of Zn and Cu from the application of 25 m3 ha-1; N from 50 m3ha-1; and P, K and Ca + Mg at the dose of 100 m3ha-1.

Soil Solution Nutrient Availability, Nutritional Status and Yield of Corn Grown in a Typic Hapludox under Twelve Years of Pig Slurry Fertilizations

Nutrient content in soil solution may vary in response to the applied amount of pig slurry (PS). Thus, the aim of this research was to evaluate the nutrient content in soil solution and its relationship to nutritional status and yield of corn under 12 years of annual fertilization with increasing doses of PS, soluble mineral fertilizer (MF) and PS combined with MF. The experiment was conducted under field conditions in a Latossolo Vermelho Distroferrico (Typic Hapludox). The treatments consisted of pig slurry at annual rates of 50 and 100 m3 ha-1 (PS50 and PS100), soluble mineral fertilizer (MF), and pig slurry at a rate of 25 m3 ha-1 complemented with mineral fertilizer (PS25 + MF), distributed in a randomized block design. Soil solution was sampled at two depths, 0.40 and 0.80 m, on six dates after the fertilizer applications. The nitrate (NO−3-N) and K levels in the soil solution were measured 40, 108 and 135 days after the last application of fertilizer (DAAF), being subsequently correlated with corn yield. PS50 provide contents of NO−3-N, P and K to the soil solution similar to those supplied by MF or PS25+MF. The critical limit of 10 mg L-1 NO−3-N in the soil solution was exceeded on 108, 135 and 230 DAAF, at rates of 100 and 50 m3 ha1 of PS and on 230 DAAF when using MF.

Microbiological activity and N transformations in a soil subjected to aggregate extraction amended with pig slurry

Pig slurry as a fertilizer source has been extensively used in agriculture; however, in order to reduce the risks of contaminating the water supplies given its high level of N sources, it is important to understand the N transformations occurring in the soil where it is applied. In this study, incubations were performed at 25 °C for a period of 63 to 73 d to evaluate the effect of different doses of pig slurry on the global microbiological activity and the N dynamics in time, with an emphasis on N mineralization and nitrification in a soil subject to aggregate extraction. The slurry was applied in doses equivalent to: 0, 162, 244, and 325 m3 ha-1, constituting four treatments: T0, T50, T75, and T100, respectively. The microbiological activity and the contents of NH4+-N and NO3-- N were measured. Increasing doses of slurry produced an increase in the evolution of the accumulated CO2, with 63.5, 115.0, 112.7, and 125.7 mg 100 g-1 soil for T0, T50, T75, and T100 respectively. A similar situation was observed in the initial contents of NH4+-N, which were 22.4, 30.3, 44.3, and 60.7 mg kg-1 in each treatment, respectively. On the other hand, the increase in NO3-- N contents were only noticed by the end of the incubation period and corresponded to 28.6, 69.0, 95.3, and 109.8 mg kg-1. In addition, the net N mineralization was predominant in all treatments with slurry during the measurement period, being 9.1, 45.4, 58.1, and 52.7 mg kg-1 for T0, T50, T75 and T100, respectively, at the end of the trial. The mineralization rate of the organic C decreased when increasing the dose of slurry and the mineralization rate of the organic N resulted to be low, which would indicate a high contribution of material resistant to degradation by the slurry, which could have a long term effect in the soil.

Nitrogen Dynamic in Soils Amended with Legislated and Extremely High Doses of Pig Slurry

The application of pig slurry as soil amendment is a common agronomic practice, but to avoid environmental hazards the doses are regulated. This article evaluates the N dynamic in two calcareous soils amended with legislated (170 kg N, D1) and high doses (1700 kg N, D2) of pig slurry and incubated for 300 days. Nitrification increased at the end of incubation (39–45 and 154–285 mg kg−1 in control, D1, and D2). Net N mineralization was similar in all soils (24–36 mg kg–1), but negative in D2 in soil 1 (–72 mg N kg−1). Soil type was an important factor for nitrification processes, with greater rates in the soil with high calcium carbonate content and with no effects on ammonification. Thus, legislated doses compared to control could be considered a wise practice. Conversely, overdoses displayed potential N processes influenced by the carbonate content and the salinity of the amended soil.

Soil tillage to reduce surface metal contamination – model development and simulations of zinc and copper concentration profiles in a pig slurry-amended soil

Long-term applications of organic amendments, such as pig slurry (PS), may represent environmental risk of soil and water pollution by trace metals (TM). Our objective was to examine different soil and manure management scenarios that enhance the long-term agricultural use of soils under repetitive PS applications while avoiding environmental risk. Firstly, we developed a new module for simulating the impacts of soil tillage frequencies in Hydrus-1D. Secondly, we used a previously validated modeling approach to predict the surface accumulation and movement of the TM during the next 100-year in the soil under different PS doses (80 and 40m3ha−1cultivation−1) and tillage frequencies (no-tillage and 20, 10, and 5-year tillage). No-tillage simulations revealed consistent TM surface accumulations, reaching the soil threshold value for Cu in the 0–20cm layer after 86 years of PS amendments at high doses, but in layers 0–5, 0–10, and 5–10cm, this concentration was already reached after 17, 38, and 75 years, respectively. While soil tillage reduced TM concentrations over the top 20cm of the soil profile, it increased their transfer to deeper layers. Periodical soil tillage each 5, 10, and 20 years was found to allow PS applications without reaching the Cu threshold value in soil during 100 years. However, soil solution concentrations of Zn reached the threshold values for groundwater. Therefore, the best manure management practice for the long-term PS disposal with respect to Zn and Cu concentrations in soil is the application of moderate PS rates.

Matéria orgânica e atributos físicos de um Latossolo Vermelho após aplicações de dejeto de suínos

A atividade suinícola gera grande quantidade de dejetos que podem ser utilizados como fertilizante em áreas de lavouras e pastagens. A adição continuada desses dejetos pode alterar os atributos físicos do solo. Neste trabalho objetivou-se verificar a influência da aplicação de doses 0, 48, 96, 144, 192 e 240 m³ ha-1 ano-1, de dejeto líquido suíno durante quatro anos, num Latossolo Vermelho com pastagem perene. O teor médio de matéria seca do dejeto líquido de suínos foi de 1,72%. Amostras de solo com estrutura preservada e não preservada foram coletadas nas camadas de 0-0,05; 0,05-0,10; 0,10-0,15; 0,15-0,20; 0,20-0,25 e 0,25-0,30 m. Avaliaram-se o teor de matéria orgânica, a argila dispersa em água, a densidade do solo e dos sólidos e a relativa, a resistência à penetração, a porosidade total e o volume de macro, micro e criptoporos, a permeabilidade do solo ao ar e a estabilidade dos agregados do solo. Com exceção do teor da matéria orgânica não houve interação entre doses e camadas. Os atributos físicos avaliados não foram influenciados pela aplicação das diferentes doses de dejeto líquido de suínos com matéria seca de 1,72%, por um período de quatro anos em Latossolo Vermelho.

Combined pig slurry and mineral fertilization for corn cultivation

The objective of this work was to evaluate the environmental effects of the use of pig slurry to irrigate the corn crop grown in a typical Red Distroferric Latosol and in leachate composition. Twenty four lysimeters, filled with soil, in a protected environment, received five doses of pig slurry (0; 112.5; 225; 337.5 and 450 m³ ha-1 per growing cycle) combined with two mineral fertilization doses (50 and 75% of the recommended dose - 80 kg ha-1of nitrogen). Corn height and yield were evaluated, as well as nutrients in the soil and in leachate. From the results obtained in the first year of experiment, it was concluded that the concentrations of nitrate increased by increase of pig slurry application, and thus, it would be necessary to develop further studies in medium and long term.

Frações de fósforo no solo após sucessivas aplicações de dejetos de suínos em plantio direto

O objetivo deste trabalho foi quantificar as frações de acumulação de fósforo em solo submetido a sucessivas aplicações de dejetos líquidos de suínos (DLS) em sistema de plantio direto. Em Santa Maria, RS, doses de 0, 20, 40 e 80 m³ ha-1 de DLS foram distribuídas a lanço por sete anos agrícolas, antes do plantio de cada cultivo de inverno ou verão, em Argissolo Vermelho arenoso, totalizando 0, 584, 1.168 e 2.336 kg ha-1 de P aplicado via dejetos. O solo foi coletado nas camadas 0-2, 4-6, 8-10, 14-16 e 20-25 cm, e submetido ao fracionamento químico de P. A adição do DLS ao solo durante sete anos aumentou o teor de P até 25 cm de profundidade, principalmente nas frações inorgânicas extraídas por resina trocadora de ânions, NaHCO3 0,5 mol L-1 e NaOH 0,1 mol L-1. As aplicações não aumentaram os teores de P orgânico extraído por NaHCO3 0,5 mol L-1, mas sim as frações orgânicas extraídas por NaOH 0,5 e 0,1 mol L-1. O DLS adicionado ao solo por longo período pouco afeta a partição de P em frações inorgânicas e orgânicas. As sucessivas aplicações de DLS aumentam o acúmulo de P em frações predominantemente lábeis no solo, o que representa um risco potencial para contaminação de águas superficiais e subsuperficiais.