Frações de carbono e nitrogênio mineralizável no solo em sistema de integração lavoura-pecuária

• Autor(a) principal: Laurito, Henrique Fontellas
• Data de Publicação: 2021
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/216931
• topic: Fertilidade do solo; Matéria orgânica no solo; Lavoura; Pecuária

In research on soil management, organic matter is often fractionated, with emphasis on the labile fraction, which is the most sensitive to changes in management and the most directly associated with nutrient cycling. This sensitivity allows to save time to recommend the best strategies or propose adjustments in management to increase soil quality and sustainability of production systems. The objective of this study was to evaluate the physical fractions of carbon (Coarse and Fine Particulate Organic Carbon and Organic Carbon Associated with Minerals) and mineralizable organic N in an Integrated Crop-Livestock System (ICLS) in which different corn and marandu grass sowing systems were evaluated in the integration. The experiment was installed in 2015 at the Research Center for Beef Cattle of Sertãozinho, belonging to the Institute of Animal Science/APTA/SAA. The design of the experiment was randomized blocks with six treatments and three replications. The treatments were: Tillage (corn for grains); Livestock (marandu grass); ICLS1: corn plus marandu grass with simultaneous sowing in planting fertilization; ICLS2: corn plus marandu grass with simultaneous sowing in planting fertilization + application of nicosulfuron herbicide; ICLS3: corn plus marandu grass with marandu grass sowing in corn cover fertilization; ICLS4: corn plus marandu grass with simultaneous sowing of marandu grass in the corn line and between line + application of the herbicide nicosulfuron. The experiment was conducted until January 2018, when soil samples were collected at depths of 0-10 cm and 10-20 cm. Part of the collected soil volume was incubated for 28 days at 25°C (incubated samples) and the other part was kept at room temperature (non incubated samples) and, in incubated and non-incubated samples, carbon fractions and mineralized nitrogen were determined in 28 days of incubation. In the statistical analysis, monoculture corn and grass and sowing systems within the ICLS were considered the main treatments, and the depths, the secondary ones. The effects of treatments on POC levels before incubation and mineralized N were evaluated using variance analysis by f-test and comparison of means by Tukey test. Particulate organic carbon was higher in crop-livestock integration systems, particularly in ICLS1 (marandu-grass plus corn with simultaneous sowing in planting fertilization) and ICLS3 (marandu-grass corn with marandu grass sowing in corn cover fertilization). The sowing and management systems did not influence the mineralized nitrogen content. In the layer from 0 to 10 cm there was a higher content of mineralized nitrogen, particulate organic carbon and associated with minerals.