In no-tillage systems, there is an accumulation of crop residues (CR), which plays an essential role in the availability of soil-N. A study was set up to provide information regarding the N credit and the influence of N mineral fertilizer. There was the addition of a similar rate of residue (10 Mg ha?1; sugarcane, soybean, and brachiaria) and N mineral fertilizer (urea; 120 kg N ha?1) in loam soil. After the stabilization of biological activity (73 days), soil and remaining residues were collected, and C and N monitored. The results showed that the N credit was positive with the application of soybean, sugarcane, and brachiaria. There was a positive balance of the soybean N credit in soil with a reduction from 2.49 to 0.90 g kg?1 of N in remaining residue, and a direct increase of 90% of soil-N. There is no need of N fertilizer to potentialize the soybean N credit, but it is required to potentialize N credit of brachiaria and sugarcane. The urea demonstrated to be an excellent enhancer of brachiaria N credit, but it was not adequate for sugarcane residues. Based on our result, the accumulation and incorporation of CR can be considered as N credit with a positive contribution in soil-N.
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机译：在无耕作系统中，庄稼残留物（Cr）积累，这在土壤-N的可用性中起着重要作用。建立了一项研究，以提供有关N信贷的信息和N矿物肥料的影响。添加了类似的残基速率（10mg ha = 1;甘蔗，大豆和brachiaria）和N矿物肥料（尿素; 120kg n Ha-1）。在稳定生物活性（73天）后，收集土壤和剩余的残留物，并监测C和N。结果表明，N信贷与大豆，甘蔗和Brachiaria的应用是阳性的。大豆N信用的阳性平衡在土壤中减少2.49至0.90g kg？1的剩余残留物中，直接增加90％的土壤-N。不需要N肥料来潜在大豆N信贷，但需要潜入Brachiaria和甘蔗的N Credit。尿素表明是Brachiaria N信用的优秀增强剂，但它不适用于甘蔗残留物。根据我们的结果，CR的积累和掺入可被视为N信贷，并在土壤-N中具有积极贡献。
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