Disponibilidade e mineralização do nitrogênio após aplicações sucessivas de lodo de esgoto no solo, estimadas por meio de incubação anaeróbica

Abstract

Resumo -O objetivo deste trabalho foi avaliar, por meio de incubação anaeróbica, a mineralização e a disponibilidade de N em solos tratados com aplicações sucessivas de lodo de esgoto, e determinar o efeito residual das aplicações anteriores na taxa de mineralização do nitrogênio (TMN). Dois experimentos de longa duração foram realizados com doses anuais de lodo de esgoto, para o cultivo de milho: um com dose recomendada de lodo, correspondente a 120 kg ha -1 de N, e 2, 4 e 8 vezes essa dose, em área da Embrapa Meio Ambiente, em Jaguariúna; e outro com 80 kg ha -1 de N aplicado via adubo mineral, e 1 e 2 vezes a dose recomendada de lodo de esgoto, em área do Instituto Agronômico, em Campinas; além de testemunha, sem aplicação de lodo. A disponibilidade de N e a TMN foram estimadas em condições de campo e por incubações anaeróbicas em laboratório. O N total absorvido pelas plantas também foi determinado. O lodo de esgoto é mais efetivo em fornecer nitrogênio ao milho, em longo prazo, do que a adubação mineral. O efeito residual do lodo de esgoto não influencia a TMN do lodo recém-adicionado. O método de incubação anaeróbica é eficiente em estimar a mineralização do N proveniente de lodo de esgoto recém-adicionado.Termos para indexação: Zea mays, acúmulo de nitrato, efeito residual, fertilização orgânica, resíduo orgânico.Nitrogen availability and mineralization after successive sewage sludge applications on soil, estimated through anaerobic incubationAbstract -The objective of this work was to evaluate, through anaerobic incubation, N mineralization and availability in soils treated with successive applications of sewage sludge, and to determine the residual effect of previous applications on nitrogen mineralization rate (NMR). Two long-term experiments were conducted with annual sewage sludge doses for corn cultivation: one with the recommended dose of sewage sludge, correspondent to 120 kg ha -1 N, and 2, 4, and 8 times the dose in area at Embrapa Meio Ambiente, in Jaguariúna, in the state of São Paulo, Brazil; and the other with 80 kg ha -1 mineral N fertilization, and 1 and 2 times the recommended dose of sewage sludge in area at Instituto Agronômico, in Campinas, in the state of São Paulo, Brazil; besides a control, without sewage sludge application. N availability and NMR were determined in field conditions and through anaerobic incubations in laboratory. Total nitrogen absorbed by plants was also estimated. Sewage sludge is more effective in supplying nitrogen to corn in the long term than mineral fertilization. The residual effect of sewage sludge does not influence the NMR from newly-added sludge. The method of anaerobic incubation is efficient in estimating the mineralization of N from newly-added sewage sludge.Index terms: Zea mays, nitrate accumulation, residual effect, organic fertilization, organic waste. IntroduçãoO uso agrícola do lodo de esgoto no Brasil é regulamentado pela Resolução Conama n o 375 (Brasil, 2006), na qual estão indicados os critérios e os procedimentos para seu uso adequado. Ent...

Agricultural use and pH correction of anaerobic sewage sludge with acid pH

“…similar to soil conditioners and organic fertilizers (Table 1). The evaluation of ASS indicated similar values to those found in literature for organic carbon (21-32%), nitrogen (1.09-4.2%), phosphorus (0.56-4.2%), calcium (3.42-3.82%), magnesium (0.14-1.93%), sulfur (0.89-2.68%) and manganese (120-400 mg kg − 1 ), however, the pH (5.4-7.9) and potassium content (0.2-1.5%) were lower than those previously found in the literature, while values for aluminum (0.76-1.64%) and iron (1.03-2.60%) were larger (Bueno et al, 2011;Stemann et al, 2015;Pires et al, 2015;Pesonen et al, 2016;Ren et al, 2015;Herzel et al, 2016;Kodešová et al, 2019). These differences were probably due to particularities in the anaerobic digestion process.…”

Grain Yield and Microbiological Quality of Cowpea Plants Grown Under Residual Effect of Sewage Sludge Fertilization1

“…The highest GY found for the cultivars under residual fertilization of sewage sludge was attributed to the improvement of soil chemical and physical characteristics, mainly by the increase in organic matter and decrease in soil density (Table 3), which contribute for higher availability of nutrients, especially nitrogen, since this element limits cowpea grain yield because it is the most extracted nutrient by the crop (TAGLIAFERRE et al, 2013). The nitrogen in the sewage sludge is predominantly organic (PIRES et al, 2015), and is gradually mineralized over time and made available to plants (ZARE; RONAGHI, 2019). Thus, nitrogen can be kept longer in soils fertilized with sewage sludge than in soils fertilized with high-solubility fertilizers, which results in increases in grain yield.…”

Organic Nitrogen in Agricultural Systems

“…Siqueira et al [24] found that in soil under NT system for 12 and 22 years, the averages for N mineralization were 0.19 and 0.26 g m −2 day −1 , respectively. For organic compounds such as sludge, the N mineralization rate is generally below 50%, 5-38% [25], 14-43% [26], 7-16% [27], and 24-31% [28]. Among the species used in straw production, Fabaceae plants stand out for fixing atmospheric N 2 and presenting low C/N ratio tissues, in addition to the high soluble compound content and low lignin and polyphenol contents.…”