• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>STI/PUB/1285; Consultants Meeting on Management Practices for Improving Sustainable Crop Production in Tropical Acid Soils; 19990501-03; Vienna(AT) >NITROGEN DYNAMICS IN SOYBEAN-BASED CROP ROTATIONS UNDER CONVENTIONAL AND ZERO TILLAGE IN BRAZIL
【24h】

NITROGEN DYNAMICS IN SOYBEAN-BASED CROP ROTATIONS UNDER CONVENTIONAL AND ZERO TILLAGE IN BRAZIL

机译：巴西常规耕作和零耕下大豆作物轮作中的氮动力学

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Approximately 70% of Brazilian agriculture is based on the cultivation of highly weathered soils located in tropical and subtropical savannah areas, where the zero or no tillage (ZT) system is now considered as the best alternative to the traditional conventional tillage (CT). During the period 1999-2004 the Agrobiology Centre of Embrapa implemented a research program using nuclear and related techniques to study the main processes involved in the dynamics and cycling of N for predominant crop rotations grown at five locations under ZT in comparison to CT, on acidic savannah soils of both southern and Cerrado regions of Brazil. The most relevant results of these studies were: (1) The soybean crop derived a high proportion of its N (over 80%) from biological nitrogen fixation (BNF). The BNF system is so efficient that attempts to increase grain yields by addition of N fertilizer are hardly ever successful as long as the plants have been effectively inoculated with the recommended Bradyrhizobium strains. (2) The N fertilizer use efficiency by the maize crop fertilized with 80 to 90 kg N ha~(-1) varied from 40 to 60%. (3). A maximum 10% of N-urea applied broadcast over the soil surface (40 kg N ha~(-1)) in a maize crop was lost via NH_3 volatilization, with the highest values under ZT. (4) The inclusion of green manure legumes (GMLs) such as lupin and vetch, which are highly efficient in BNF was essential to promote a positive soil N balance in crop rotations and to increase the stock of soil organic C. (5) Less than 900 g N-N_2O ha~(-1) yr~(-1) were lost from the soil surface, and the highest values were found under CT. (6) Even thought the contribution of BNF to the Brazilian soybean crop is high (over 80%), the accurate assessment of this input to the soil N balance still remain unclear due to methodological problems using the leaf labeling technique to estimate residual below-ground N. Results obtained so far suggest that these methodological issues need to be overcome before these estimates can be considered as reliable. These results demonstrate the enormous potential impact of BNF in legumes such as soybean and green manures and their management under ZT and CT on the N cycling processes and overall C and N stocks in tropical acid savannah soils, thus contributing to the productivity and sustainability of the agricultural production systems.
机译：巴西约有70％的农业是基于热带和亚热带稀树草原地区高风化土壤的耕种而来的，在该地区，零耕或免耕（ZT）系统现在被认为是传统传统耕作（CT）的最佳选择。在1999年至2004年期间，Embrapa农业生物学中心实施了一项利用核及相关技术的研究计划，以研究与酸性条件下相比，在CT下，ZT下五个位置生长的主要农作物轮作过程中N的动态变化和循环的主要过程。巴西南部和塞拉多地区的稀树草原土壤。这些研究的最相关结果是：（1）大豆作物的氮的很大一部分（超过80％）来自生物固氮（BNF）。 BNF系统是如此有效，以至于只要添加了推荐的缓生根瘤菌菌株，就很难通过添加氮肥来提高谷物产量。 （2）80〜90 kg N ha〜（-1）施肥的玉米作物的氮肥利用效率在40％至60％之间变化。 （3）。通过NH_3挥发，玉米作物在土壤表层（40 kg N ha〜（-1））上传播的N-脲最多损失10％，在ZT下最高。 （4）包括羽扇豆和v子等绿肥豆科植物（GML），它们在BNF中非常有效，对于促进作物轮作中土壤氮素的正平衡和增加土壤有机碳的储量至关重要。（5）较少从土壤表面流失了900 g N-N_2O ha〜（-1）yr〜（-1），在CT下发现了最高值。 （6）即使使用BNF对巴西大豆作物的贡献很高（超过80％），由于使用叶标技术估算低于以下水平的残留量的方法学问题，仍无法准确评估此输入对土壤氮平衡的准确度-地面N.迄今为止获得的结果表明，在将这些估计值视为可靠之前，需要克服这些方法问题。这些结果表明，BNF对豆类（如大豆和绿肥）及其在ZT和CT下的管理对热带酸性稀树草原土壤中的N循环过程以及总C和N储量的巨大潜在影响，从而有助于BNF的生产力和可持续性。农业生产系统。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号