Estoques de carbono orgânico e de nitrogênio no solo em sistema de integração lavoura-pecuária em plantio direto, submetido a intensidades de pastejo

Abstract

RESUMOSistemas de integração lavoura-pecuária têm um alto potencial de uso no sul do país, especialmente em áreas de soja sob plantio direto, com espécies de cobertura no inverno. A condução de sistemas de integração com diferentes intensidades de manejo da pastagem resultará, ao longo do tempo, em estoques de C orgânico (CO) e de N diferenciados, decorrentes do aporte diferenciado de resíduos. Este trabalho foi realizado para avaliar a evolução dos estoques de CO e de N total (NT) e em frações físicas da matéria orgânica em solo submetido a diferentes intensidades

Microbial Characteristics of Soils Under an Integrated Crop-Livestock System

“…However, the period of establishment of the system may be a determining factor. Souza et al (2009) observed C losses at a high grazing intensity (10 cm), and C increases at moderate grazing intensities (20 and 40 cm) or with no grazing following three years of ICL with no tillage.…”

Soil carbon and nitrogen stocks in traditional agricultural and agroforestry systems in the semiarid region of Brazil

“…The main constituents of SOM are C (52-58 %) and N (3.7-7 %); the soil levels and pools of these elements vary according to the application rates of plant and animal residues and to the losses resulting from erosion and oxidation by soil microorganisms (Souza et al, 2009). SOM is involved in the balance between the C and N cycles, and its content is stable in soils under native vegetation (Bortolon et al, 2009).…”

“…In traditional agricultural systems tillage is usually more intense, leading to erosive losses and increased microbial activity due to the greater exposure of organic residues to microorganisms and their enzymes Souza et al, 2009). These conditions result in decreased levels of C and N and, consequently, increased C-CO 2 emissions into the atmosphere and decreased N cycling (Sharma et al, 2005).…”

“…These conditions result in decreased levels of C and N and, consequently, increased C-CO 2 emissions into the atmosphere and decreased N cycling (Sharma et al, 2005). Conversely, conservation systems that prioritize the organic residue input and reduced tillage, including no-tillage (Souza et al, 2009;Maia et al, 2010), agrosilvopastoral systems (Maia et al, 2007;Aguiar et al, 2010), silvopastoral systems Tonucci et al, 2011), and organic farming , have proved efficient in maintaining and sometimes raising the soil C and N levels (Maia et al, 2008).…”

“…An understanding of the organic matter dynamics in soils requires temporal studies, since changes in the soil organic matter and interactions that result from adopted management practices tend to appear gradually (Souza et al, 2009). In this context, this study assumes that in the long term, AFSs increase the total soil organic C and N stocks, evaluating the changes in total soil C and N stocks under agroforestry (silvopastoral and agrosilvopastoral) and traditional agricultural systems by comparing these systems to the natural vegetation of Caatinga, after 13 years of cultivation in a typical Ortic Chromic Luvisol, in the semiarid region of Ceará, Brazil.…”