Effects of combined conservation practices on soil and water quality in the Central Mississippi River Basin
Effects of combined conservation practices on soil and water quality in the Central Mississippi River Basin
复制标题
密西西比河流域中部土壤和水质综合保护措施的影响
DOI：
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发表时间：
2020
影响因子：
3.9
通讯作者：
N. Kitchen
中科院分区：
文献类型：
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作者：
C. Baffaut;F. Ghidey;R. Lerch;Kristen S. Veum;E. Sadler;K. Sudduth;N. Kitchen
粘土土壤的常规耕作由于径流量大和相关的土壤侵蚀而导致土壤和水质退化。古德沃特溪实验流域，这是美国农业部农业研究服务基准保护效果评估项目，流域评估研究的一部分，建立解决这些问题。小区研究强调了侵蚀控制和除草剂或养分径流之间的权衡。有必要对减少径流造成的沉积物、养分和除草剂损失的综合措施进行长期的实地评估。位于密苏里州的36公顷田地在常规玉米（Zea mays L.）- 大豆（Glycine max L.）1993年至2003年采用春季播种前施肥和耕作的系统。从2004年到2014年，实施了由两个主要管理区定义的精准农业系统：小麦（Triticum aestivum L.）大豆占60%，玉米和大豆占40%。该系统包括免耕，覆盖作物，莠去津分次应用的基础上杂草的压力，变量率的氮（N），和变量率的下降施加磷（P）。本研究的目的是比较径流水质从两个管理系统，流量和负荷持续时间曲线，累积分布函数，并从复制的地块研究的结论。精准农业系统并不影响年径流量，但它确实增加了低流量的频率。由于免耕和覆盖作物，泥沙流失减少了87%。阿特拉津和磷的损失低于预期，尽管缺乏纳入土壤。阿特拉津的损失可能较低，因为小麦面积作为缓冲区，阿特拉津的吸附和保留在外地，更快的衰减。溶解磷损失的一部分，应用保持不变，可能是因为更大的吸附和较低的径流风险时，应用P.最后，硝酸盐-N（NO3-N）的损失减少，导致整体减少的N损失，尽管略有增加铵-N（NH 4-N）的损失。包括更大的土壤含水量，不同的施氮时间，覆盖作物的氮吸收。在这些成功的基础上，提出了一个理想的管理系统，以进一步提高精准农业系统的性能和实用性。
Conventional cultivation of claypan soils leads to soil and water quality degradation because of high runoff and associated soil erosion. The Goodwater Creek Experimental Watershed, which is part of the USDA Agricultural Research Service Benchmark Conservation Effects Assessment Project, Watershed Assessment Studies, was established to address these issues. Plot studies have highlighted trade-offs between erosion control and herbicide or nutrient runoff. There is a need for long-term field-scale evaluation of combined practices that reduce sediment, nutrient, and herbicide losses by runoff. A 36 ha field located in Missouri was under a conventional corn (Zea mays L.)–soybean (Glycine max L.) system from 1993 to 2003 with fertilizer application and tillage prior to planting in the spring. A precision agriculture system defined by two main management zones was implemented from 2004 to 2014: wheat (Triticum aestivum L.) and soybean in 60% of the field, and corn and soybean in the remaining 40%. The system included no-till, cover crops, atrazine split-applications based on weed pressure, variable rates of nitrogen (N), and variable rates of fall-applied phosphorus (P). The objective of this study was to compare runoff water quality from the two management systems, based on flow and load duration curves, cumulative distribution functions, and conclusions from replicated plot studies. The precision agriculture system did not affect annual runoff, but it did increase the frequency of low flows. Sediment losses were reduced by 87% as a result of no-till and cover crops. Atrazine and P losses were lower than expected, despite the lack of incorporation into the soil. Atrazine losses were possibly lower because of the wheat area acting as a buffer, greater atrazine adsorption and retention in the field, and faster decay. Dissolved P losses as a fraction of applied remained the same, likely because of greater adsorption and lower runoff risk when applying P. Finally, nitrate-N (NO3-N) losses decreased and resulted in an overall decrease of N losses despite a slight increase of ammonium-N (NH4-N) losses. Explanations included a greater soil water content, a different timing of N applications, and N uptake by cover crops. Building on these successes, an aspirational management system is proposed to further improve on the performance and practicality of the precision agriculture system.