Organic matter and phosphorus fractions in irrigated agroecosystems in a semi-arid region of Northeastern Brazil (original) (raw)
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The development of management strategies aiming to increase soil quality in Brazilian semi-arid regions, including the improvement of soil organic matter (SOM) status, is still scarce. In general, most of the traditional farming practices adopted in agricultural fields in Northeast Brazil (semi-arid) contribute to reduce SOM levels. Thus, alternative management practices must be implemented to improve soil quality in different agricultural production systems. Within this context, agroforestry and organic farming have been considered suitable management options to cope with the semi-arid climate despite of its environmental constraints. This study aimed at presenting results from well established experiments on agroforestry and organic farming performed in Sobral, Guaraciaba do Norte and Ubajara counties, all located in the State of Ceará, Brazil. In agroforestry, agrosilvopastoral and silvopastoral designs may be considered as important options to increase soil organic C stocks, with consequences in the different SOM pools, including labile C. Organic farming has been implemented in both small and large scale agriculture, and it also represents a good strategy to increase the status of SOM, even in sandy soils as observed at Ubajara county. Obviously, agronomic, economic and social aspects should be linked to the environmental benefits brought about through the adoption of agroforestry and/or organic cultivation. Notwithstanding, the discussion involving the improvement of food production in Brazilian semi-arid must regard both types of agroecosystems as suitable options to increase the status of SOM, which represents the starting point for recovering soil quality, and consequently, enhancing productivity.
Soil organic matter pools under management systems in Quilombola Territory in Brazilian Cerrado
Revista Brasileira de Engenharia Agrícola e Ambiental, 2017
The aim of this study was to evaluate the stable and labile fractions of soil organic matter and carbon (C) management index in cultivated areas with conservation and conventional management used by Quilombola farmers in the Goiás state, Brazil. The management systems were studied in the areas of Cerradão: Native Cerrado; Pasture; Conventional grain cultivation; Conservation cultivation of perennial crop; and in the sensu stricto Cerrado: Native Cerrado; Natural pasture; Conventional grain cultivation; Conventional cultivation of perennial crop. The study was considered as observational, with five replicates. Total organic C, fractions of humic substances, labile C and C management index were determined. The Cerradão phytophysiognomy had the highest total organic C values and stable soil organic matter fractions. The native areas had low levels of labile C. The conservation cultivation of perennial crop showed the largest accumulation of total organic C in the different fractions of...