| View Larger Image | Effect of wheat crop fertilization on nitrogen dynamics and balance in the Humid Pampas, Argentina [An article from: Agriculture, Ecosystems and Environment] | Digitalby A. Abril (Author), D. Baleani (Author), N. Casado-Murillo (Author), L. Noe (Author)
| List Price: | $10.95 | | | Available: | Available for download now |
| | Binding: | Digital | | Publisher: | Elsevier | | Page Count: | 5 Pages | | Publication Date: | February 01, 2007 |
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Product Description
This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: Water contamination by nitrates has increased international awareness. It is widely accepted that massive fertilizer application is the principal factor responsible for water nitrate contamination. During the last years, Argentina has extraordinarily increased the use of fertilizers, particularly on wheat (Triticum aestivum L.). However, few studies have quantified nitrate losses. Here we report N dynamics in soil fractions and N balance in wheat crops in Marcos Juarez, province of Cordoba (Argentina) with the aim of determining nitrate loss and its possible influence on water contamination. Four treatments were studied to evaluate the combined effect of tillage systems and N fertilizer doses on N losses in soil 0-20cm in depth. The treatments analyzed were: (a) conventional tillage, non-fertilized (CT 0N), (b) no-till and 25kgNha^-^1 (NT 25N), (c) no-till and 50kgNha^-^1 (NT 50N), and (d) no-till and 140kgNha^-^1 (NT 140N). Determinations were: soil total N, NO"3^--N, NH"4^+-N, microbial biomass N, crop residue biomass, crop residue N, and grain N. N balance was calculated as the difference in N fractions between harvest and sowing samples. N balance was negative in all treatments evaluated; the highest N loss (-1075kgNha^-^1) occurred with the highest fertilization rate (140kgNha^-^1). Losses of microbial and soluble N fractions were significant at the end of the crop cycle in all the treatments analyzed (15 and 40%, respectively), probably due to leaching by high precipitations (250mm). Much of the N lost was soil organic matter N, a fact seldom considered in other N balances. Furthermore, it was observed that neither yield efficiency nor the remaining N increased significantly with the highest fertilization dose (140N). Our data show that high doses of nitrogen fertilizer result in low N utilization efficiency and a high risk of water contamination by nitrates. |
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