Estoque de carbono e atributos físicos de um Latossolo Vermelho em diferentes sistemas de manejo

Abstract

RESUMOO objetivo deste trabalho foi avaliar as modificações nos estoques de carbono, resíduos vegetais da superfície do solo (RVS) e em alguns atributos físicos do solo, tais como densidade do solo (Ds), densidade das partículas (Dp) e volume total de poros (VTP) em diferentes sistemas de manejo, no cerrado goiano; para isto foram selecionados no sudoeste do estado de Goiás, quatro diferentes tipos de manejo, a saber: sistema plantio direto (SPD) com integração lavoura-pecuária (ILP), SPD sem ILP e áreas de Cerrado natural (CN) e pastagem (PA); em cada uma das áreas foram coletadas amostras nas profundidades de 0-5; 5-10 e 10-20 cm; o delineamento utilizado foi o inteiramente casualizado; o tratamento com CN apresentou, em todas as profundidades analisadas (0 a 20 cm) menores valores de Ds, e o maior VTP, do que as demais tratamentos avaliados. Dentre os sistemas manejados a área de ILP e o SPD apresentaram menores Ds que a PA na camada superficial do solo, no entanto, não houve diferença entre esses sistemas de manejo para a Dp e VTP. A área de CN apresentou RVS e EstC semelhantes ao SPD e ILP na camada superficial do solo; já a ILP apresentou EstC semelhante a área de CN na camada de 10-20 cm.Palavras-chave: cerrado integração lavoura-pecuária, matéria orgânica do solo, pastagem, sistema de plantio direto Carbon stock and physical attributes of an Oxisol under different management system ABSTRACTThe objective of this study was to evaluate the changes in carbon stocks, crop residues from the soil surface (RVS), and some soil physical properties such as bulk density (Ds), particle density (Dp) and total pore volume (VTP) under different management systems in the 'Cerrado goiano'. For this, in the southwestern part of Goiás state four different types of management were selected, namely: no-tillage (NT) with crop-livestock integration (ILP), NT without ILP and natural areas of 'Cerrado' (CN) and pasture (PA ). In each area, soil samples were collected in 0-5, 5-10 and 10-20 cm depths. The experimental design was completely randomized. Treatment with CN presented in all depths studied (0 to 20 cm) lower values of Ds and the VTP higher than other treatments. Among the management systems, the area of ILP and NT had lower Ds than the PA in the topsoil, however, there was no difference between these management systems for Dp and VTP. The area of CN presented EstC similar to the RVS and NT and ILP in the topsoil, while the ILP presented EstC similar to NC area in 10-20 cm.

Soil carbon and nitrogen stocks, light organic matter, and remaining phosphorus under a crop-livestock integration system

“…The Cst did not differ between the PP and the PC in the 0.00-0.20 m layer (Table 3). Higher Cst values in areas with native vegetation, such as the NCA, than cultivated areas under NTS and CLI have been reported previously (GUARESCHI et al, 2012;ROSSI et al, 2012;BATISTA et al, 2013;GAZOLLA et al, 2013GAZOLLA et al, , 2015BEUTLER et al, 2015). This is probably because the NCA has characteristics that promote SOM stability, such as the continuous deposition of plant residues (litterfall) and roots with different C/N ratios, perennial vegetation, and no soil disturbance (GUARESCHI et al, 2012).…”

“…The absence of statistical differences in Cst between the cultivated areas (NTS and CLI) could also be attributed to the short implementation times of the management systems, because the Cst in areas under conservation management systems require many years (≥8 years), depending on the edaphoclimatic conditions, to recover their C stocks to levels close to those under the original conditions (Cerrado native vegetation) (PEREIRA NETO et al, 2007;SILVA et al, 2011;GUARESCHI et al, 2012;GAZOLLA et al, 2013). This absence of sensitivity of Cst under CLI was confirmed by the LOM results, i.e., the Cst was not affected, but some SOM compartments, such as LOM, changed, which may have influenced soil Cst dynamics, depending on how long the system had been implemented.…”

“…Soil Cst and Nst under CLI tend to increase over time, and, sometimes, even equalize and exceed the values found in native Cerrado vegetation areas (NCA) and areas with NTS without grazing (SOUZA et al, 2009;LOSS et al, 2012b;GAZOLLA et al, 2013). This increase is caused by a combination of several factors, such as high shoot and root production by grasses, cattle manure, deposition of plant residues from annual crops, and fertilization (SOUZA et al, 2009;LOSS et al, 2012c).…”

“…The most suitable CLI conditions are strictly related to the edaphoclimatic conditions of the region (LEMAIRE et al, 2014;SALTON et al, 2014). Previous studies have evaluated several soil quality indicators in the Cerrado biome, including the light organic matter (LOM) content (LOSS et al, 2011(LOSS et al, , 2012a, carbon (Cst) and nitrogen (Nst) stocks (SOUZA et al, 2009;GAZOLLA et al, 2013), soil density (SD) (FLORES et al, 2007;CONTE et al, 2011;BONETTI et al, 2015), and remaining phosphorus (Prem) (BIELUCZYK, 2014;BEUTLER et al, 2015;BEZERRA et al, 2015), and have compared different CLI systems and/or grazing intensities with areas without grazing and/ or native vegetation.…”

Estoque de carbono e atributos físicos de um Latossolo em cronossequência sob diferentes manejos

“…Campos et al (2013) relataram que o plantio direto por nove anos em Latossolo Amarelo distrófico acumulou mais C no período seco, com 44,9 e 26,75 Mg ha -1 para as camadas de 0-20 e 20-40 cm, respectivamente em comparação ao período chuvoso. Considera-se que a similaridade no estoque de C entre as áreas de cerrado natural e sistema plantio direto nas camadas superficiais do solo decorre do maior aporte de resíduos vegetais depositados na superfície do solo (Gazolla et al, 2013). Corroborando esses resultados, Guareschi et al (2012) também constataram, ao avaliar uma cronossequência Médias seguidas da mesma letra não diferem entre si pelo teste de Tukey (p < 0,05).…”