ABSTRACT: This study evaluated P pools after nine years of successive application of either pig slurry (PS) or deep pig litter (DL) in a no-till Ultisol from southern Brazil. The experiment was established in Dec 2002 with the treatments control, application of 90 and 180 kg N ha−1 N as PS and as DL. In Mar 2010, soil samples were taken at six layers up to 30 cm deep. Total organic and inorganic P were assessed by the ignition method, and P compounds classes were evaluated by 31P-NMR spectroscopy. Total soil P increased proportionally with the P amount applied via DL and PS. Only DL application increased soil organic P, mainly at the highest dose and in the uppermost soil layers. The application of high doses of manure to these soils under no-till to meet crop N demands significantly increased P accumulation at the soil surface, especially with DL. This, in turn, increases the risk of contamination of water bodies due to P transfer from soil to rivers via runoff. The ignition method overestimates organic P compared to P-NMR. The highest proportion of organic P estimated by the ignition and P-NMR methods, at surface layers in the control suggests that inorganic P is added to the plots treated, increasing inorganic P and decreasing organic P. Moreover, with no P additions to the control, inorganic soil P is removed by plants, causing an apparent increase in the organic P proportion.
ABSTRACT The phosphorus (P) rates recommended for corrective fertilization-P of soils from southern Brazil may be insufficient to reach the critical level for optimal plant growth. This study aimed to quantify the fertilizer-P rates for total correction fertilization with varying soil buffering capacity in the states of Rio Grande do Sul (RS) and Santa Catarina (SC). Soil samples from 0.00-0.10 and 0.10-0.20 m layers were collected from 41 locations distributed in both states. Twelve P rates were applied to each soil, varying between 0 and 100 % of the maximum adsorption capacity (P-max), and incubated for 20 days. After incubation, the extractable P was determined by Mehlich-1. Based on the relationship between applied rates and extracted P, the P buffer capacity (trP_M1) of the soils was quantified, relating it to soil properties. The trP_M1 values, that is, amounts of P2O5 required to increase 1 mg dm-3 of P extracted by Mehlich-1, varied between 2.4 and 34.5 kg ha-1 of P2O5. A multiple explanatory equation for the variable P was generated, in which only P-max, clay content, and initial P availability have a significant effect. The P buffer capacity was significantly higher in the soils with the highest clay content, and there was a reduction in trP_M1 for soils with higher initial P availability. Considering 270 soil samples with low P, the P rate to reach the sufficient levels may be 2-folds higher than the values currently indicated for the RS and SC states, especially for soils with more than 40 % of clay. Phosphorus rates for corrective fertilization must be based on the soil clay content and in P initial availability. The fertilizer-P in clayey soils must be increased.
ABSTRACT The overloading of soil with manure or mineral fertilizers enhances phosphorus (P) availability, promoting its loss to water bodies and increasing the risk of eutrophication. In this sense, the establishment of an environmental P threshold is a simple and useful tool to classify soils regards its risk of P losses. Here we propose a P-threshold for soils from the state of Rio Grande do Sul (RS) in Brazil, with the soil clay content as the principal variable of the model. Samples from 20 representative soils of Rio Grande do Sul State were collected in the 0.00-0.10 and 0.10-0.20 m layers. Samples were physically and chemically characterized and incubated with P rates varying from 0 to 100 % of its maximum adsorption capacity. After 20 days of incubation, the P availability was determined in water and Mehlich-1 extractant. We assessed trough segmented linear functions the value of P-Mehlich in which the levels of P water enhance abruptly (i.e., breaking point) to determine the P limit for each soil. Subsequently, the P limit values were linked to the clay content in the sample, adopting the linear equation arising from it as the P-threshold. Adding a safety margin of 20 % to the P-threshold equation, we propose a simplified one “P-threshold = 20 + clay”. Based on the current critical level of P adopted by the regional recommendation in RG, the equation proposed does not limit the production of the most crop species.
Abstract: The objective of this work was to evaluate changes in phosphorus fractions in a Humic Cambisol cultivated with vineyards, after 62 years of additional fertilization with poultry litter. Soil samples were collected from two vineyards (V1 and V2) and a forested area adjacent to them. A total of 1,365 and 910 kg ha-1 P were applied to V1 and V2, respectively, throughout the past 62 years. Samples were collected at 0-10, 10-20, 20-30, and 30-40-cm soil depths for the analysis of soil physicochemical properties. The addition of poultry litter to the soil of the vineyards increased the contents of inorganic P (Pi) in all fractions, except in the residual fraction (residual-P), mainly at the 0-10-cm soil depth, in comparison with the forested area. The addition of poultry litter as fertilizer does not affect the organic P (Po) stock in the Humic Cambisol, it only increases the Pi contents of the soil.
Resumo: O objetivo deste trabalho foi avaliar as modificações de frações de fósforo em um Cambissolo Húmico cultivado com vinhedos, após 62 anos de fertilização adicional com cama-de-aves. Amostras de solo foram coletadas de dois vinhedos (V1 e V2) e de uma área de floresta (F) adjacente a eles. Foram aplicados 1.362 e 910 kg ha-1 de P ao V1 e ao V2, respectivamente, durante os últimos 62 anos de cultivo. Amostras de solo foram coletadas a 0-10, 10-20, 20-30 e 30-40 cm de profundidade, para análises das propriedades físico-químicas do solo. A adição de cama-de-aves ao solo dos vinhedos aumentou os teores de P inorgânico (Pi) em todas as frações, exceto na fração residual, principalmente à profundidade de 0-10 cm, em comparação à área de floresta. A adição de cama-de-aves como fertilizante não afeta os estoques de P orgânico (Po) do Cambissolo Húmico, apenas aumenta os teores de Pi do solo.
ABSTRACT Use of organic fertilizers in integrated crop-livestock (iCL) systems may affect soil phosphorus fractions. This study aimed to determine phosphorus fractions in the soil under the iCL system after six years of application of organic or mineral fertilizers. The experiment was conducted on a Rhodic Kandiudox (Nitossolo Vermelho Distroférrico) in a randomized block design, using a 5 × 3 + 1 factorial scheme, with four replicates. The treatments consisted of three organic fertilizers (poultry litter, pig slurry, and compost) and two mineral fertilizers (M1, equivalent to pig slurry; and M2, equivalent to poultry litter) in interaction with three application rates, corresponding to 75, 100, and 150 % of the fertilizer recommendation for the crop of interest and a control (with no fertilizer). Soil sampling was performed in the 0.00-0.05, 0.05-0.10, and 0.10-0.20 m layers for determination of the phosphorus fractions. Successive use of organic or mineral fertilizers for six years in the iCL system considerably raises the labile and moderately labile P fractions up to the 0.20 m depth and, with less intensity, raises the non-labile fractions up to the 0.10 m depth. The soil P increase associated with fertilizer input raises soybean and corn yields, and it does not exceed the critical P limit according to local environmental legislation.
ABSTRACT: Potential soil acidity can be measured by two methods in the states of Rio Grande do Sul (RS) and Santa Catarina (SC): solution SMP or solution TSM (Buffer Santa Maria). Calibration of these methods is done by incubating soils for long periods (180 days) of CaCO3. The hypothesis of this study is that it is possible to reduce the incubation period in soils by using a soluble base such as calcium hydroxide. The study aimed to estimate potential acidity in a group of soils by moist incubation with Ca(OH)2 (short) as an alternative to the typical method with CaCO3 (long) and relate to the values estimated by the equation used by the Soil Chemistry and Fertility Commission of Rio Grande do Sul and Santa Catarina (CQFS-RS/SC; 2016). Ten soils with sandy texture and low organic matter content were collected at 0-20cm in the Campanha Gaúcha region of the state of RS and incubated for 180 days with doses of CaCO3 equivalent to 0, 25, 50, 75, 100, 125 and 150% of the lime requirement estimated by the solution TSM to raise to pH 6.0. Soils were also incubated for 4 days in an oven at 35ºC with 0.22mol L-1 Ca(OH)2 at doses equivalent to CaCO3. Short incubation of the soil with Ca(OH)2 may substitute long incubation with CaCO3. Also, estimating potential acidity using the equation of the CQFS-RS/SC (2016) overestimated potential acidity in soils with solution TSM pH values lower than 6.0 in this study.
RESUMO: A acidez potencial do solo pode ser medida por dois métodos nos estados do Rio Grande do Sul (RS) e Santa Catarina (SC): índice SMP ou solução TSM (Tampão Santa Maria). A calibração destes métodos é feita pela incubação de solos por longos períodos (180 dias) com quantidades crescentes de CaCO3. A hipótese deste estudo é que é possível reduzir o período de incubação em solos usando uma base solúvel como o hidróxido de cálcio. O trabalho objetivou estimar a acidez potencial em um grupo de solos por meio de incubação úmida com Ca(OH)2 (curta) como alternativa ao método típico com CaCO3 (longa) e relacionar com os valores estimados pela equação utilizada pela CQFS-RS/SC (2016). Dez solos com textura arenosa e baixo conteúdo de matéria orgânica foram coletados a 0-20cm na região da Campanha Gaúcha e incubados por 180 dias com doses de CaCO3 equivalentes a 0, 25, 50, 75, 100, 125 e 150% da exigência de calcário estimada pela solução TSM para elevar o pH a 6,0 (longa). Os solos foram também incubados por 4 dias em estufa a 35ºC com 0,22mol L-1 de Ca(OH)2 em doses equivalentes ao CaCO3 (curta). A incubação curta do solo com Ca(OH)2 pode substituir a incubação longa com CaCO3. Além disso, a estimativa da acidez potencial utilizando a equação do CQFS-RS/SC (2016) superestimou a acidez potencial de solos com valores de pH em solução TSM inferiores a 6,0 neste estudo.
ABSTRACT Phosphorus extractors (P) Mehlich 1 (M-1), Mehlich 3 (M-3) and Anion Exchange Resin (RTA) show sensitivity to soil clay content. Also, the use of equations for conversion of available P extracted by M-3 into equivalent values of M-1 may not be adequate for a set of contrasting soils. The objective of this work is to evaluate the influence of clay content on the extraction of P by M-1, M-3 and RTA, as well as to evaluate the effectiveness of using the equation proposed by Local Soil Fertility Committee to convert M-3 contents to equivalent values of M-1. It was selected 301 farmers’ soil samples from the soil test laboratory at Santa Catarina State University, distributed in four classes of clay: 0-20, 21-40, 41-60 and > 60% clay. The samples were prepared and the available P was extracted by M-1, M-3 and RTA. M-3 and RTA extracted 12 and 11% more P than M-1, M-1 extracted less P than M-3 and RTA in sandy soils and extracted more P than others in clayey soils. The equation suggested by Local Soil Fertility Committee for converting M-3 values to equivalents in M-1 underestimated P values by up to 24%. Therefore, it is proposed to use the equation P-M1eq (mg dm-3) = (P-M3 / (1.38-0.01 * Arg)). The evaluated methods present sensitivity to soil clay content, and the classification of P availability should be performed by texture bands.
RESUMO Os extratores de fósforo (P) Mehlich 1 (M-1), Mehlich 3 (M-3) e Resina Trocadora de Ânions (RTA) apresentam sensibilidade ao conteúdo de argila do solo. Ainda, o uso de equações para conversão do P disponível extraído por M-3 em valores equivalentes de M-1 pode não ser adequado para um conjunto de solos contrastantes. O objetivo do trabalho é avaliar a influência do conteúdo de argila na extração de P por M-1, M-3 e RTA, bem como avaliar a efetividade de utilização de equações para conversão dos teores por M-3 em valores equivalentes de M-1. Foram selecionadas 301 amostras de solo no laboratório de rotina do CAV/UDESC, distribuídos em quatro classes de argila: 0-20, 21-40, 41-60 e > 60% de argila. As amostras foram preparadas e foi extraído o P disponível por M-1, M-3 e RTA. Os extratores M-3 e RTA extraíram quantidades de P 12 e 11% superiores ao M-1, respectivamente. M-1 extraiu menos P que M-3 e RTA em solos de textura arenosa e extraiu mais P que os demais extratores em solos de textura argilosa. A equação sugerida pela CQFS - RS/SC (2016) para conversão dos teores de M-3 para equivalentes em M-1 subestimou os valores de P em até 24%. Com isso, alternativamente, se propõe a utilização da equação P-M1eq (mg dm-3) = (P-M3 / (1,38-0,01*Arg)). Os métodos avaliados apresentam sensibilidade ao teor de argila do solo, devendo ser realizada a classificação da disponibilidade P por faixas de textura.
ABSTRACT The purpose of this study was to evaluate Cu and Zn migration and fractions in sandy soil of vineyards. In Urussanga (SC), Brazil, soil samples were collected from a 4-year-old and 15-yearold vineyard, and from a forested area. In the soils, the chemical characteristics of Cu and Zn were analyzed by the EDTA method, which determines the fraction available in soil; 3050B method of the USEPA for total concentrations, which represents the pseudo-soil contents in the soil; and chemical fractionation, which estimates soluble fraction, exchangeable fraction, fraction associated with clay minerals, fraction associated with organic matter and residual fraction. The results show that there is accumulation of Cu and Zn in sandy soils cultivated with grapevines and with frequent fungicide applications. These higher levels were found in soils with longer cultivation time (15 years old), but were restricted to the superficial layers of the soil. Most of the Cu was extracted by EDTA method, and it may be considered as available to plants. The EDTA also extracted a small part of Zn. Most of the Cu in the vineyard soils can be characterized by low geochemical mobility, but in the uppermost soil layers of the oldest vineyard, there was an increase in Cu content associated with soil organic matter. Most of the Zn in the vineyard soil was associated with minerals, which indicates low mobility and also low potential for toxicity to plants and microorganisms.
ABSTRACT: The objective of this study was to compare two methods of evaluation of potencial acidity (H+Al) and two methods to estimate liming requirement (LR) for soils from the west region of Santa Catarina State, Brazil. Fourteen soils were incubated with 7 lime rates for 120 days, obtaining the real values of H+Al at pH 7.0 and LR. These values were used as reference to evaluate the accuracy of two H+Al estimating methods: SMP buffer and calcium acetate at pH 7.0, and to evaluate the accuracy of two LR methods: base saturation (BS) and SMP index. On average, H+Al was underestimated in 6 and 40% by SMP and calcium acetate methods, respectively, especially in soils with high buffer capacity. The LR was underestimated in 20 and 30% by SMP index and BS, respectively. The SMP Index showed a better LR estimative than BS, especially in soils with high buffer capacity.
RESUMO: O estudo objetivou comparar dois métodos de avaliação de acidez potencial (H+Al) e de estimativa da necessidade de calagem (NC) para solos da região Oeste de Santa Catarina (SC). Quatorze solos foram incubados com 7 doses de calcário durante 120 dias, obtendo-se ao final os valores reais de H+Al a pH 7,0 e a NC dos solos. Esses valores serviram de referência para avaliar a exatidão dos métodos de estimativa do H+Al: tampão SMP e acetato de cálcio a pH 7,0 e a exatidão dos métodos de estimativa da NC: índice SMP e saturação por bases (V%). Em média, o H+Al foi subestimado em 6 e 40% pelos métodos SMP e acetato de cálcio, respectivamente, sendo mais problemático nos solos de maior tamponamento. Já a NC foi subestimada em 20 e 30% pelo Índice SMP e V%, respectivamente. O índice SMP estimou melhor a NC que o método V%, principalmente em solos de maior tamponamento.
ABSTRACT: Weed management in apple orchards (Malus domestica) can affect the leaching of nitrogen (N) in soil. The study aimed to evaluate the potential leaching of N forms in soil of an apple orchard with different weed management treatments. The experiment was conducted in an apple orchard implanted in 2008. In October 2011, 80 plants were selected and the following treatments were implemented: no weed management (NM), desiccation of weeds on the tree row with herbicide use (DR) and mechanical mowing of weeds on the tree row (MR). Yield was evaluated in the 2011/2012, 2012/2013 and 2013/2014 crop seasons. In May 2012 porous cup lysimeters were installed in the NM, DR and MR treatments. In the solution collected at 0.20m, NH4 +-N and NO3 --N were analyzed sixteen times and mineral N concentration was calculated. The highest concentrations of NO3 --N and mineral N occurred in soil solution with DR, which increases availability of the nutrient to apple trees, but also enhances the potential losses. Weed management and N flow in the solution did not affect apple yield.
RESUMO: O manejo de plantas espontâneas em pomares de macieira (Malus domestica) pode afetar a lixiviação de nitrogênio (N) do solo. O trabalho objetivou avaliar a lixiviação de formas de N em solo sob pomar de macieiras com diferentes manejos de plantas espontâneas. O experimento foi conduzido em um pomar de macieira implantado em 2008. Em outubro de 2011, foram selecionadas 80 plantas e implantados os tratamentos: sem manejo das plantas espontâneas (SM); dessecamento das plantas espontâneas na linha de plantio com uso de herbicidas (DL) e roçada mecânica das plantas espontâneas na linha de plantio (RL). Nas safras 2011/2012, 2012/2013 e 2013/2014 foi avaliada a produtividade. Em maio de 2012 foram instalados lisímetros com cápsula porosa nos tratamentos SM, DL e RL; e na solução coletada a 0,20m em dezesseis épocas foram analisados NH4 +-N e NO3 --N, e calculado o teor de N-mineral. Os maiores teores de NO3 --N e mineral-N ocorreram na solução no solo com DL, o que aumenta a disponibilidade do nutriente às macieiras, mas também potencializa as perdas. O manejo de plantas espontâneas e o fluxo de N na solução não afetaram a produtividade de maçã.
ABSTRACT Phosphorus (P) applications at dosages higher than the necessary may cause P buildup in the soil labile fractions and, consequently, pollution of water sources. This study aimed to assess accumulation of P fractions as well as the parameters of adsorption isotherms in soil profiles having a history of application of phosphate fertilizers and cultivated with apple trees. Soil samples were collected from an area with no history of cultivation and 2 apple orchards cultivated for 8 (P8) and 18 (P18) years, in the city of Urubici, Santa Catarina, southern Brazil. Soil samples were air dried, sieved in a 2-mm mesh, and subjected to chemical analyses (P adsorption) besides P chemical fractionation. Applications of phosphate fertilizers to the orchards, particularly P18, increased the inorganic and organic concentrations of P in all fractions. The distribution of P in organic and inorganic forms in the planted soils was similar to the distribution observed for the native vegetation soil. The highest inorganic labile P fraction, the lowest maximum P adsorption capacity, and the highest equilibrium concentration values at P18 are indicators of a higher environmental pollution risk of the orchards soils compared to the native soil.
ABSTRACT The injection of nitrogen sources into the soil and use of nitrification inhibitor can improve the efficiency of applied nitrogen and minimize losses to the environment. The objective of this study was to evaluate the effect of swine slurry (SS) and urea in two modes of application in the soil (injected and surface), and the use of nitrification inhibitor on NH3 volatilization in a controlled environment, upon varying soil texture and soil pH conditions. The experiment was conducted under controlled conditions, or a Rhodic Kandiudox and Typic Hapludult soil in a completely randomized design in a 4 x 2 x 2 x 2 factorial design with three replications. The study evaluated four fertilizers (urea, SS, SS +nitrification inhibitor (dicyandiamide-DCD) and control), two pH conditions (natural and limed) and two forms of fertilizer application (injected and surface), and two soils. The SS rate used was 21 m3 ha-1, and the rate of the inhibitor was 10 kg ha-1. The evaluations consisted in daily accumulated ammonia volatilization up to 14 days, and the percentage of soil nitrogen loss. The injection of fertilizers reduced emissions of ammonia in both soils and, limed soil had higher N losses by volatilization. The inhibitor did not increase the emission of ammonia in both soils.
RESUMO A injeção de fontes de nitrogênio no solo e o uso de inibidor de nitrificação podem melhorar a eficiência do nitrogênio aplicado e minimizar perdas para o ambiente. O objetivo deste trabalho foi avaliar o efeito do DLS e da ureia em dois modos de aplicação no solo (injetado e superficial), e o uso de inibidor de nitrificação sobre a volatilização de NH3 em ambiente controlado, com condições variadas de textura e pH do solo. O experimento foi conduzido em condições controladas, em um Nitossolo e um Argissolo, com delineamento inteiramente casualizado, em esquema fatorial 4 x 2 x 2 x 2 com três repetições. Avaliou-se quatro fertilizantes (ureia, dejeto líquido suíno, dejeto líquido suíno+inibidor de nitrificação (dicianodiamida-DCD) e testemunha), duas condições de pH (natural e corrigido), duas formas de aplicação dos fertilizantes (injetado e superficial), e dois solos. A dose de dejeto suíno foi de 21 m3 ha-1, e a do inibidor foi de 10 kg ha-1. As avaliações consistiram em mensuração da volatilização de amônia diária e acumulada até o 14º dia, e da porcentagem de N perdido em relação ao aplicado. A injeção reduziu as emissões de amônia em ambos os solos, e a correção do pH favoreceu as perdas de N por volatilização. O inibidor não aumentou a emissão acumulada de amônia em ambos os solos.
Abstract: The objective of this work was to evaluate phosphorus forms in grape leaves and their relationships with must composition and yield in grapevines grown in a Typic Hapludalf with different available P contents. Two experiments were carried out with Vitis viniferacultivars, one with 'Tannat' and the other with 'Cabernet Franc' grapes. Experiment 1 consisted of two vineyards of 'Tannat', with the following P content in the soil: V1, 11.8 mg kg-1 P; and V2, 34.6 mg kg-1 P. Experiment 2 consisted of two vineyards of 'Cabernet Franc', with the following P content in the soil: V1, 16.0 mg kg-1 P; and V2, 37.0 mg kg-1 P. Leaves were collected at flowering (FL) and veraison (V), and, after their preparation, P forms were evaluated. Yield and must composition were assessed. The highest yield was observed in V2 of experiment 1 and in V2 of experiment 2. Total P content and P forms in leaves at FL and V have no relationship with yield parameters; however, total P content in leaves has a relationship with anthocyanin content in the must of 'Tannat' grapevines. Therefore, P fractionation in leaves predicts neither grapevine yield nor must composition.
Resumo: O objetivo deste trabalho foi avaliar as formas de fósforo em folhas e suas relações com a composição do mosto e a produção em videiras cultivadas em um Argissolo Vermelho distrófico típico, com diferentes teores de P disponível. Dois experimentos foram realizados com cultivares de Vitis vinifera, um com uvas 'Tannat' e outro com 'Cabernet Franc'. O experimento 1 consistiu de dois vinhedos de 'Tannat', com os seguintes teores de fósforo no solo: V1, 11,8 mg kg-1 de P; e V2, 34,6 mg kg-1 de P. O experimento 2 consistiu de dois vinhedos de 'Cabernet Franc', com os seguintes teores de fósforo no solo: V1, 16,0 mg kg-1 de P; e V2, 37,0 mg kg-1 de P. Coletaram-se as folhas ao florescimento (FL) e ao início da maturação (IM), e, após a preparação delas, analisaram-se as formas de P. A produtividade e a composição do mosto foram avaliadas. A maior produtividade foi observada no V2 do experimento 1 e no V2 do experimento 2. O teor total de P e suas formas nas folhas ao FL e IM não apresentam relação com os parâmetros produtivos; no entanto, o teor de P total nas folhas apresenta relação com o teor de antocianinas no mosto de videiras 'Tannat'. Portanto, o fracionamento de P nas folhas não prediz a produtividade da videira nem a composição do mosto.
ABSTRACT Applications for long periods of organic animal waste as a source of nutrients to crops can contaminate the soil and the surface and subsurface waters. This study aimed to evaluate how the utilization of organic waste, after successive applications, affects P fractions in the soil and consequently environmental contamination. In an experiment conducted for 8 years, totaling 12 applications with pig slurry manure (PSM), liquid cattle manure (LCM), swine deep bedding (SDB), and mineral fertilizer (NPK), 460; 505; 1.111; and 535 kg P∙ha−1 were added to the soil through PSM, LCM, SDB, and NPK, respectively. In September 2012, soil samples were collected in the layers 0.0 – 0.04; 0.04 – 0.08; 0.08 – 0.12; 0.12 – 0.16; 0.16 – 0.20 m, prepared and subjected to a sequential chemical fractionation of P. The 12 applications of pig slurry, liquid cattle manure, swine deep bedding and NPK fertilizer for eight years (urea + triple superphosphate + potassium chloride) provided accumulations of P fractions in the soil that were above the necessary for a proper nutrition to plants considering the available P fractions (AER + organic NaHCO3 + inorganic NaHCO3) in the soil. In addition, they showed that the use of swine deep bedding, followed by pig slurry, means higher levels of available P fractions in the soil. In this sense, the establishment of a dosage of organic waste to meet the nitrogen need of crops is not an environmentally appropriate parameter. It may cause P accumulation in the soil, increased absorption ability of plants and soil support, contributing to environmental contamination.
ABSTRACT In Southern Brazil, agricultural soils are often treated over long periods with annual pig slurry (PS) applications, and their influence on soil nutrient dynamics should be monitored. This study aimed to evaluate the P forms accumulated in the soil and some biological and biochemical parameters of the P cycle after 19 successive PS applications over eight years, in a no-tillage (NT) system. Pig slurry was applied at rates of 0, 20, 40, and 80 m3 ha-1 per crop. Several P forms (available P, microbial P, phosphatase enzyme, total organic and inorganic P) in the 0.00-0.05 and 0.05-0.10 m soil layers were analyzed. Increases up to 5,523 % in available P, 308 % in microbial P, 104 % in phosphatase enzyme activity, 91 % in organic P, 251 % in inorganic P, and 19 % in Total-P were observed in the 0.00-0.05 m soil layer in response to the highest PS rate compared to the treatment with no PS. Results also indicated that P added via PS was preferentially accumulated in the inorganic fractions (83-98 %). The increase in organic P was limited by the increase in soil organic carbon. The increase in soil microbial biomass-P was more influenced by available P, while the increase in phosphatase enzyme activity was more related to the increase in organic P and C. Therefore, PS applied to the soil affected the chemical, biological, and biochemical components of the soil P cycle. Results indicate that even half of the PS rate normally used by farmers (20 m3 ha-1) poses a high risk of pollution of water bodies by runoff from these soils.