Organic matter and phosphorus fractions in irrigated agroecosystems in a semi-arid region of Northeastern Brazil

• Published in: Agriculture, ecosystems & environment Vol. 138; no. 1; pp. 74 - 82
• Main Authors: de Assis, Cristiane Pereira, de Oliveira, Teógenes Senna, da Nóbrega Dantas, Joana d’Arc, de Sá Mendonça, Eduardo
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15-06-2010; Amsterdam; New York: Elsevier; Elsevier
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; agroecosystems; Agronomy. Soil science and plant productions; annuals; Apodi; bananas; Biological and medical sciences; Carbon; corn; Cultivation; Eutrophication; fruit crops; Fundamental and applied biological sciences. Psychology; General agroecology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; grain crops; Hard surfacing; humic substances; Irrigated cultivation; irrigated farming; Irrigation. Drainage; land management; land use; Musa; nitrogen; perennials; Phosphorus; Reduction; Reserves; semiarid zones; Soil (material); soil depth; soil fertility; Soil management; soil organic carbon; Soil organic matter; Soil phosphorus; soil quality; Vegetation; Zea mays; Brazil; South America; America; Brazil, Ceara; Soil organic matter; Soil phosphorus; Irrigated cultivation; Soil management; Irrigation; Soils; Organic matter; Semi arid zone; Phosphorus; Ecology; Culture; Agroecosystem
• ISSN: 0167-8809; 1873-2305
• DOI: 10.1016/j.agee.2010.04.002

The main goal of agricultural management practices in irrigated agroecosystems in the Brazilian semi-arid is either to maintain or increase soil quality. In these areas, the reduction in soil quality is mainly associated with depletion of soil organic matter (SOM), as well as of soil phosphorus (P) reserves. We aimed to evaluate changes in SOM and P fractions of a eutrophic haplic cambisol (Eutric Cambisol) under different uses and management systems in the irrigated perimeter of Jaguaribe/Apodi in Ceará State, Brazil. The evaluated irrigated agroecosystems were perennial banana (
Musa ssp.) cultivation (IPBC) and annual maize (
Zea mays L.) cultivation (IAMC). The respective natural vegetation (NVIB) and (NVIM) were selected and used as a reference. Soil samples were collected at 0–5, 5–15, 15–25, and 25–40
cm soil depths, and evaluated for total organic carbon (TOC), total nitrogen (TN), humic substances, fractions of oxidizible organic carbon, and organic and inorganic P fractions. The stocks of TOC, TN, and humic substances in topsoil have been reduced by cultivation, and the largest reductions were observed in the IAMC area. The degree of SOM oxidation decreased with soil depth and the greastest amounts of labile C were found in IAMC. Annual and perennial agroecosystems showed changes in reserves of soil P. Our results pointed out that irrigated agroecosystems in the Brazilian semi-arid regions need to adopt management practices that favor the building up of soil SOM contents, particularly where annual crops are cultivated.