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.

A aplicação de dejetos de animais no solo pode aumentar a disponibilidade de fósforo às plantas e potencializar a transferência do nutriente pela solução escoada ou percolada. Este trabalho objetivou avaliar o efeito de sucessivas aplicações de fontes orgânicas e mineral de nutrientes sobre o teor disponível, o escoamento superficial e a percolação de formas de P em um Argissolo Vermelho manejado sob sistema plantio direto. O experimento 1 foi desenvolvido em 2004 na área experimental do Departamento de Solos da Universidade Federal de Santa Maria, em Santa Maria, RS, sob plantio direto. Os tratamentos foram testemunha (sem aplicação de nutrientes), dejeto líquido de suínos (DLS), cama sobreposta de suínos (CSS), dejeto líquido de bovinos (DLB) e fertilizante mineral (NPK), sendo as doses determinadas para suprir a necessidade de N das culturas. Durante o ano agrícola de 2010/2011 (cultivo de aveia-preta e milho), após cada evento (chuva + escoamento ou percolação), foi coletada solução e determinaram-se os teores de P-solúvel, total e particulado. Em novembro de 2008, amostras de solo foram coletadas estratificadas de 2 em 2 cm, até 20 cm; de 5 em 5 cm, até 40 cm; e 10 em 10 cm, até 70 cm. O solo foi seco, moído e determinado o teor de P extraído pela resina trocadora de ânions (RTA). No experimento 2, os tratamentos foram solo; solo + DLS; solo + CSS; solo + DLB; e solo + NPK. Após 20, 35, 58, 73 e 123 dias de incubação, foram determinados os teores de P extraído por RTA. As aplicações de fontes de nutrientes ao longo dos anos proporcionaram incremento e migração de P-disponível no perfil do solo, refletindo em transferências de P por escoamento superficial e percolação, especialmente no solo com a aplicação de DLS e CSS, onde foi realizada a maior adição do nutriente. Os teores de P disponível no solo e as transferências de P por escoamento superficial correlacionam-se com as quantidades aplicadas, independentemente da fonte de P utilizada. Porém, a transferência de P por percolação não se correlacionou com a quantidade aplicada do nutriente, mas sim com a quantidade de solução percolada no perfil do solo.

The application of animal manure to soil can increase phosphorus availability to plants and enhance transfer of the nutrient solution drained from the soil surface or leached into the soil profile. The aim of this study was to evaluate the effect of successive applications of organic and mineral nutrient sources on the available content, surface runoff and leaching of P forms in a Typic Hapludalf in no-tillage systems. Experiment 1 was set up in 2004 in the experimental area of UFSM, in Santa Maria (RS, Brazil). The treatments consisted of: control (without nutrient application) and application of pig slurry (PS), pig deep-litter (PL), cattle slurry (CS), and mineral fertilizers (NPK). The rates were determined to meet the N crop requirements of no-tillage black oat and maize, grown in the 2010/2011 growing season. The soil solution was collected after each event (rain + runoff or leaching) and the soluble, particulate and total P contents were measured. In November 2008, soil was collected in 2 cm intervals to a depth of 20 cm, in 5 cm intervals to a depth of 40 cm, and in 10 cm intervals to a depth of 70 cm. The soil was dried and ground, and P determined after extraction by anion exchange resin (AER). In experiment 2, samples collected from the Typic Hapludalf near experiment 1 were incubated for 20, 35, 58, 73 and 123 days after applying the following treatments: soil, soil + PS, soil + PL, soil + CS and soil + NPK. Thereafter, the soil was sampled and P was analyzed by AER. The applications of nutrient sources over the years led to an increase in available P and its migration in the soil profile. This led to P transfer via surface runoff and leaching, with the largest transfer being observed in PS and PL treatments, in which most P was applied. The soil available P and P transfer via surface runoff were correlated with the amounts applied, regardless of the P source. However, P transfer by leaching was not correlated with the applied nutrient amount, but rather with the solution amount leached in the soil profile.

As videiras em produção tendem a aproveitar pequena quantidade do N, derivado do fertilizante mineral, mesmo cultivadas em solos com textura arenosa e baixo teor de matéria orgânica, o que confere a esses solos baixa capacidade de fornecimento de nitrogênio (N). O objetivo deste trabalho foi avaliar, por meio de incubação, a disponibilidade de nitrogênio (N) em solo com histórico de cultivo com videiras e submetido à aplicação de fontes minerais e orgânicas de nutrientes. Foram coletadas amostras de um Argissolo Vermelho, em um vinhedo e em uma área sob campo natural, no município de Rosário do Sul (RS). Após o preparo do solo, foram montados os seguintes tratamentos: solo do campo nativo; solo do vinhedo; solo do vinhedo + composto orgânico; solo do vinhedo + ureia revestida com polímeros e solo do vinhedo + ureia. Os solos foram incubados por 141 dias, e aos 0, 38, 70, 102 e 141 dias de incubação, foram determinados os teores de N-NH4+ e N-NO3-, e calculados os teores de N mineral, mineralização líquida, N mineralizado em relação ao total e o N mineral acumulado. No solo de vinhedo submetido à aplicação de ureia revestida com polímeros e de ureia, a maior mineralização de N aconteceu no período inicial. A liberação de N do composto orgânico tem um maior sincronismo com a necessidade da videira pelo nutriente. As reservas de N total potencialmente mineralizável do solo podem suprir a demanda da videira pelo N.

The objective of this study was to evaluate the nitrogen (N) availability in a soil with history of growing vines and submitted to application of mineral and organic sources of nutrients. In October 2010, samples of a Sandy Typic Hapludalf soil were collected in a vineyard and in a natural pasture soil, in the municipality of Rosario do Sul (RS). The treatments consisted of: natural pasture and vineyard soil as control; vineyard soil + organic compost; vineyard soil + polymer coated urea and vineyard soil + urea. The soils were incubated and subsamples were taken at 0, 38, 70, 102 and 141 days of incubation to determine N-NH4+ and N-NO3- contents. Concentrations of mineral N, net mineralization, N mineralization in relation to the total N and mineral buildup were calculated. In vineyard soils submitted to application of the polymer coated urea and urea, most N mineralization occurred in the initial period. Nitrogen release from the organic compound has better synchronicity with the vine requirements. The soil reserves of total nitrogen potentially mineralized may supply the vine demand for N.