Carbono orgânico em neossolo quartzarênico recuperado com lodo de esgoto sob espécies nativas da Mata Atlântica
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Data
2017-08-09
Autores
Goulart, Lívia Mara Lima
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O experimento, iniciado em 2005, visou nesta etapa avaliar a fertilidade do solo, o C orgânico total e o estoque de C no solo, as alterações na quantidade de C microbiano e sua atividade enzimática (β-glicosidase, desidrogenase, fosfatase e arilsulfatase), a qualidade da MOS e a emissão de CO2 em decorrência da aplicação de fertilizante orgânico composto em Neossolo Quartzarênico recuperado com lodo de esgoto sob espécies nativas da Mata Atlântica. Os tratamentos foram: 10, 20, 30, 40 e 50 Mg ha-1 de fertilizante orgânico com suplementação de K; adubação mineral convencional; dose de K utilizada como suplementação para o composto; e tratamento controle. A coleta das amostras de solo foram realizadas antes da aplicação dos tratamentos e após 6 meses. O solo foi amostrado nas camadas de 020, 20-40, 40-60, 60-80 e 80-100 cm. Nas amostras da primeira (prévia à aplicação dos tratamentos) coleta e após seis meses foram realizadas análise química básica, de micronutrientes, densidade e C orgânico total. Logo após a aplicação dos tratamentos foi quantificada a emissão de CO2 do solo e nas amostras coletadas após 6 meses foram realizados as análises do fracionamento físico e químico da MOS, da atividade enzimática e do C microbiano. O C estocado no solo em cada uma das épocas foi determinado multiplicando-se o teor de C orgânico total pelo volume e densidade do solo de cada camada amostrada do sistema. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade. Os resultados dos tratamentos com as doses de lodo de esgoto e fertilizante orgânico foram analisados por regressão, quando significativo. Nos resultados preliminares, a adição de lodo de esgoto, em sua maior dosagem (20 Mg ha-1) diminuiu o pH do solo e proporcionou um aumento nas demais variáveis analisadas, exceto na densidade do solo, Ca, Mg e SB, que não apresentaram resposta significativa à aplicação dos tratamentos. A quantificação do fluxo de CO2 do solo logo após a reaplicação dos tratamentos com fertilizante orgânico foi significativa até os 60 dias, com maiores emissões nos locais que receberam o composto. Após 6 meses da reaplicação do fertilizante orgânico, observou-se efeito significativo sobre a fertilidade do solo, carbono orgânico total e estoque de C na camada superficial do solo, no fracionamento químico e físico da MOS e nos atributos microbiológicos do solo, exceto na atividade da fosfatase ácida, sendo que as maiores médias foram observadas nos tratamentos que receberam 40 e 50 Mg ha-1 do composto. Assim, a aplicação lodo de esgoto, bem como a de fertilizante orgânico em solos degradados é útil na recuperação de suas características químicas, físicas e biológicas, pois proporciona o aumento dos níveis dos nutrientes, bem como da atividade microbiológica do solo.
The experiment, started in 2005, aimed at evaluating soil fertility, total organic C and soil C stock, changes in the amount of microbial C and its enzymatic activity (βglucosidase, dehydrogenase, phosphatase and arylsulfatase), the quality of SOM and the emission of CO2 due to the application of organic fertilizer compound in Quartzarenic Neosol recovered with sewage sludge under native species of the Atlantic Forest. The treatments were: 10, 20, 30, 40 and 50 Mg ha-1 of organic fertilizer with supplementation of K; conventional mineral fertilization; dose of K used as supplementation for the compound; and treatment control. The soil samples were collected before the application of the treatments and after 6 months. Soil was sampled in the 0-20, 20-40, 40-60, 60-80 and 80-100 cm layers. In the first samples (prior to the application of the treatments) collected and after six months were performed basic chemical analysis, micronutrients, density and total organic C. Soon after the application of the treatments, the CO2 emission of the soil was quantified and the samples collected after 6 months were analyzed the physical and chemical fractionation of the MOS, the enzymatic activity and the microbial C were performed. The C stored in the soil at each of the seasons was determined by multiplying the total organic C content by the volume and density of the soil of each sampled layer of the system. The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% probability. The results of the treatments with the doses of sewage sludge and organic fertilizer were analyzed by regression, when significant. In the preliminary results, the addition of sewage sludge, in its higher dosage (20 Mg ha-1), decreased the pH of the soil and provided an increase in the other analyzed variables, except in the density of soil, Ca, Mg and SB presented a significant response to the treatments. The quantification of soil CO2 flux after reapplication of organic fertilizer treatments was significant up to 60 days, with higher emissions at the sites that received the compound. After 6 months of reapplication of organic fertilizer, there was a significant effect on soil fertility, total organic carbon and C stock in the soil surface layer, in the chemical and physical fractionation of SOM and in soil microbiological attributes, except in the activity of the acid phosphatase, and the highest averages were observed in the treatments that received 40 and 50 Mg ha-1 of the compound. Thus, the application of sewage sludge as well as that of organic fertilizer in degraded soils is useful in the recovery of its chemical, physical and biological characteristics, as it provides the increase of nutrient levels as well as the microbiological activity of the soil.
The experiment, started in 2005, aimed at evaluating soil fertility, total organic C and soil C stock, changes in the amount of microbial C and its enzymatic activity (βglucosidase, dehydrogenase, phosphatase and arylsulfatase), the quality of SOM and the emission of CO2 due to the application of organic fertilizer compound in Quartzarenic Neosol recovered with sewage sludge under native species of the Atlantic Forest. The treatments were: 10, 20, 30, 40 and 50 Mg ha-1 of organic fertilizer with supplementation of K; conventional mineral fertilization; dose of K used as supplementation for the compound; and treatment control. The soil samples were collected before the application of the treatments and after 6 months. Soil was sampled in the 0-20, 20-40, 40-60, 60-80 and 80-100 cm layers. In the first samples (prior to the application of the treatments) collected and after six months were performed basic chemical analysis, micronutrients, density and total organic C. Soon after the application of the treatments, the CO2 emission of the soil was quantified and the samples collected after 6 months were analyzed the physical and chemical fractionation of the MOS, the enzymatic activity and the microbial C were performed. The C stored in the soil at each of the seasons was determined by multiplying the total organic C content by the volume and density of the soil of each sampled layer of the system. The data were submitted to analysis of variance and the means were compared by the Tukey test at 5% probability. The results of the treatments with the doses of sewage sludge and organic fertilizer were analyzed by regression, when significant. In the preliminary results, the addition of sewage sludge, in its higher dosage (20 Mg ha-1), decreased the pH of the soil and provided an increase in the other analyzed variables, except in the density of soil, Ca, Mg and SB presented a significant response to the treatments. The quantification of soil CO2 flux after reapplication of organic fertilizer treatments was significant up to 60 days, with higher emissions at the sites that received the compound. After 6 months of reapplication of organic fertilizer, there was a significant effect on soil fertility, total organic carbon and C stock in the soil surface layer, in the chemical and physical fractionation of SOM and in soil microbiological attributes, except in the activity of the acid phosphatase, and the highest averages were observed in the treatments that received 40 and 50 Mg ha-1 of the compound. Thus, the application of sewage sludge as well as that of organic fertilizer in degraded soils is useful in the recovery of its chemical, physical and biological characteristics, as it provides the increase of nutrient levels as well as the microbiological activity of the soil.
Descrição
Palavras-chave
Estoque de carbono no solo, Fertilidade do solo, Emissão de CO2, Fracionamento da matéria orgânica, Atributos microbiológicos do solo