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Organic matter and physicochemical attributes of a cambisol under different agricultural uses in a semi-arid region of Brazil.

2016; Southern Cross Publishing; Volume: 10; Issue: 1 Linguagem: Inglês

1835-2693

Ana Cecília da Costa Sinclair Marinho, Jeane Cruz Portela, Eulene Francisco da Silva, Nildo da Silva Dias, Francisco Souto de Sousa, A.C. Silva, Jucirema Ferreira da Silva,

Soil Carbon and Nitrogen Dynamics

In semiarid environments, it is possible to verify the fragility of soils in terms of decomposition of soil organic matter (SOM) and changes in physicochemical attributes. The objective of this study was to analyze quantitative fractions of soil organic matter (SOM) and soil's physicochemical attributes according to different agricultural uses, aiming to analyze its impact on the soil. The secondary objective was to detect which of these attributes was the most sensitive to distinguish environments. The research was conducted in the city of Governador Dix-Sept Rosado, at the Settlement Project Terra da Esperan a, located in the Chapada do Apodi-RN microregion, in a haplic eutrophic cambisol. The studied areas were native forest area (NFA), ambarella orchard area (AOA), collective area with conventional tillage with intercropping (CACTI), colluvial area (COLA), and agro-ecological zone (AEZ). Soil fertility, macronutrient and physical analyses (resistance to penetration, particle size, bulk density, particle density, analyses of total organic carbon and labile and recalcitrant fractions of SOM) were performed. The results showed that in the studied areas, soil fertility had neutral to alkaline reactions without the presence of Al3+ and H+Al, and without a high salinity. The highest organic material input in the AOA enhanced the P, Ca2+ and K+ of the soil, reduced Mg2+ and an increased resistance to penetration due to animal trampling. The agro-ecological zone had a condition similar to the native forest (NFA) regarding labile and recalcitrant carbon organic matter (SOM) fractions, reaching a carbon management index (CMI) of 111. The main components showed that some chemical parameters (P, K+ and Ca2+) and labile and recalcitrant fractions of organic matter (SOM) were indicators of environmental separation. However, the most sensitive components were labile C and CMI.