Review and Interpretation: Nitrogen Management Strategies to Reduce Nitrate Leaching in Tile-Drained Midwestern Soils
Review and Interpretation: Nitrogen Management Strategies to Reduce Nitrate Leaching in Tile-Drained Midwestern Soils
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发表时间：
2002
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通讯作者：
D. Dinnes;D. Karlen;D. Jaynes;T. Kaspar;J. Hatfield;T. Colvin;C. Cambardella
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作者：
D. Dinnes;D. Karlen;D. Jaynes;T. Kaspar;J. Hatfield;T. Colvin;C. Cambardella
农业用地的增加和人造氮肥使用量的增加。平衡植物最佳生长所需的氮量，而不到50年前，玉米(Zea Mays L.)一般来说，最大限度地减少被输送到地下水和地表水中的硝酸盐，这是与谷类作物和饲用豆类轮作种植的作物，对于每个试图了解的人来说，仍然是一个重大挑战，如紫花苜蓿(Medicago sativa L.)、红三叶草(Trifover)(Trifover)，以及提高农业养分的利用效率。Lium pratense L.)和三叶草(Melilotus spp.)本综述旨在研究过去一个世纪农业管理措施的变化如何通过生物固氮影响中西部土壤中的氮，通常是豆科植物，并确定所需的研究和管理措施的类型，以增加土壤剖面中的残留氮量。以减少非点状N3向水资源渗漏的可能性。这些残留的、生物固定的氮随着土壤固有的特性和管理措施的循环，从添加动物粪便的土壤有机质矿化的氮到中西部土壤中非点状N3的损失，N3的负荷或通过降雨沉积的影响是对地表水水质的影响，改进的N管理策略，并讨论了玉米和其他粮食作物获得N的研究需要。第二次世界大战后，人工排水系统的可用性增加，可能会对水质产生重大影响，因为它们的作用类似于浅层商业氮肥，并减少了对向地表水直接输送管道的需求。大田作物N3的非点状损失导致了作物对水资源轮作的显著减少，但这不是由任何单一因素造成的。在爱荷华州，牧草占作物选择、土壤有机质水平、水文、温度和降水模式的33.6%以上。通过减少该州排水系统总种植面积的3 389 160公顷来减少N3损失的战略包括改善二战结束后适当施氮的时间(美国环保部)。商务部，统计局使用土壤测试和植物监测，多样化作物轮作，1945年人口普查的利率)。到1997年，在覆盖作物、减少耕作、优化施氮技术等方面的牧草面积仅占全州总面积的12.8%(1393451 Hm2)，并使用硝化抑制剂。硝酸盐也可以去除总种植面积(USDA Natl.阿格里克。统计一下。通过建立湿地或生物滤池，从水中去除。1997年的研究)。将豆类纳入作物轮作，重点是了解将N3污染降至最低的方法，不再需要商业N投入，也应逐渐利用水资源的投入来教育公众关于替代生物固氮的知识。问题的复杂性和多重管理的需要、商业氮素供应的增加也使解决农业景观问题的战略变得更加容易。专业化和全国农畜生产企业分离的趋势。动物粪便不再是一种重要的作物养分来源，N是生长和繁殖所必需的，在所有生命形式的农场和除豆科作物外的农场上不再需要草地豆类作物，并开始专门种植玉米和大豆[土壤有机质(L.)相对较高的原始土壤]。[MERR.]制作。虽然有相当大的土壤有机质(SOM)，但通常必须补充土壤氮，以维持氮肥使用、食物、饲料和纤维生产的不同年份和地区之间的差异。在过去的20年里，这种耕作制度变化的净结果是一个普遍的担忧，即氮从农业上平均增加的商业氮肥非点源转移到更广泛的水资源中，在20世纪60年代中期期间增加了2.4公斤hm2(图1)，并因缺氧等问题而增加(Rabalais等人，20世纪90年代末)。商业氮肥使用量的增长(1996年)变得更加明显。为了了解中西部各州(伊利诺伊州、爱荷华州、印第安纳州、密歇根州，美国北部明尼苏达州、密苏里州、内布拉斯加州、俄亥俄州和威斯康星州)玉米和大豆种植带的氮素管理现状，有必要研究一下玉米和大豆种植带的氮肥使用量是否已经放缓，从1991年到本世纪，过去农业中商业氮肥的平均使用量增加了4公斤公顷(0.5公斤公顷/年)。这些变化包括使用不太多样化的1999年(图2)。然而，如果化石燃料企业、耕作强度的变化、农产品价格的排放大幅增加，以及化肥行业的缩写：LCD，局部压实和穹顶；LSNT，LATE USDA-ARS Natl，则商业氮肥的轮作稳步增加、作物生产和动物使用分离的趋势可能会改变。土壤耕作实验室，2150Pammel博士，Ames，IA 50011。春季硝酸盐试验；近红外；PSNT，主持2001年4月27日收到的土壤硝酸盐。*通讯作者(Dinnes@nstl.gov)。试验；SI-CD，控制排水渗灌；土壤有机质；WTM，地下水位管理。在阿格隆出版。J.94：153-171(2002)。
ricultural fields, and increased use of manufactured N fertilizers. Balancing the amount of N needed for optimum plant growth while Less than 50 yr ago, corn (Zea mays L.) was generally minimizing the NO3 that is transported to ground and surface waters grown in rotation with cereal crops and forage legumes remains a major challenge for everyone attempting to understand such as alfalfa (Medicago sativa L.), red clover (Trifoand improve agricultural nutrient use efficiency. Our objectives for lium pratense L.), and sweetclover (Melilotus spp.). this review are to examine how changes in agricultural management practices during the past century have affected N in midwestern soils Through biological N fixation, the legumes generally and to identify the types of research and management practices needed increased the amount of residual N in the soil profile. to reduce the potential for nonpoint NO3 leakage into water resources. Cycling of this residual, biologically fixed N along with Inherent soil characteristics and management practices contributing N mineralized from SOM added with animal manure to nonpoint NO3 loss from midwestern soils, the impact of NO3 loading or deposited through rainfall was the primary process on surface water quality, improved N management strategies, and through which corn and other grain crops obtained N. research needs are discussed. Artificial drainage systems can have a Following World War II, increased availability of significant impact on water quality because they behave like shallow, commercial N fertilizer and decreased demand for fordirect conduits to surface waters. Nonpoint loss of NO3 from fields age crops led to a significant reduction in crop rotations to water resources, however, is not caused by any single factor. Rather, and a general substitution of purchased N for biological it is caused by a combination of factors, including tillage, drainage, N. In Iowa, forage pasture represented more than 33.6% crop selection, soil organic matter levels, hydrology, and temperature and precipitation patterns. Strategies for reducing NO3 loss through (3 389 160 ha) of the state’s total cropped area at the drainage include improved timing of N application at appropriate end of World War II (U.S. Dep. of Commerce, Bureau rates, using soil tests and plant monitoring, diversifying crop rotations, of the Census, 1945). By 1997, forage pasture area in using cover crops, reducing tillage, optimizing N application techIowa comprised only 12.8% (1 393 451 ha) of the state’s niques, and using nitrification inhibitors. Nitrate can also be removed total cropped area (USDA Natl. Agric. Stat. Serv., from water by establishing wetlands or biofilters. Research that is 1997). Incorporation of legumes into a crop rotation focused on understanding methods to minimize NO3 contamination was no longer needed as commercial N inputs gradually of water resources should also be used to educate the public about replaced biological N fixation. the complexity of the problem and the need for multiple management The increased availability of commercial N also facilistrategies to solve the problem across agricultural landscapes. tated specialization and a national trend for separating crop and animal production enterprises. Animal manure no longer served as an important crop nutrient resource, N is essential for growth and reproduction and meadow legumes were not required on farms that of all life forms, and except for legume crops and began to specialize in corn and soybean [Glycine max virgin soils with relatively high soil organic matter (L.) Merr.] production. Although there is considerable (SOM), soil N must usually be supplemented to sustain variation among years and regions in N fertilizer usage, food, feed, and fiber production. During the past 20 yr, the net result of this farming-system change was a napublic concern regarding N movement from agricultural tional average increase in commercial N fertilizer use nonpoint sources into broader water resources has inof 2.4 kg ha 1 yr 1 (Fig. 1) between the mid-1960s and creased as problems such as hypoxia (Rabalais et al., the late 1990s. The rise in commercial N fertilizer usage 1996) became more evident. To understand current within Midwest states (Illinois, Iowa, Indiana, Michigan, questions about N management in the U.S. northern Minnesota, Missouri, Nebraska, Ohio, and Wisconsin) Corn and Soybean Belt, it is necessary to examine the has slowed, with average use of commercial N fertilizer changes that have occurred in agriculture during the past increasing by 4 kg ha 1 (0.5 kg ha 1 yr 1 ) from 1991 to century. These changes include the use of less diversified 1999 (Fig. 2). However, the trend of steadily increased crop rotations, separation of crop production and animal usage of commercial N fertilizer may change if fossil fuel enterprises, changes in tillage intensity, drainage of agprices increase substantially and the fertilizer industry is Abbreviations: LCD, localized compaction and doming; LSNT, lateUSDA-ARS Natl. Soil Tilth Lab., 2150 Pammel Dr., Ames, IA 50011. spring nitrate test; NIR, near infrared; PSNT, presidedress soil nitrate Received 27 Apr. 2001. *Corresponding author (dinnes@nstl.gov). test; SI–CD, subirrigation with controlled drainage; SOM, soil organic matter; WTM, water table management. Published in Agron. J. 94:153–171 (2002).