摘要
盖子庄稼能由增加碳(C) 供应在土壤微生物学上有有益的效果，但是这些有益的效果能被降水条件调制。这研究的目的是比较休闲冬季小麦(Triticum aestivum L.) 旋转到在在半干旱的美国高平原的 rainfed 和灌溉条件下面的几盖子庄稼冬季小麦旋转。实验在科罗拉多在二个地点，在内布拉斯加的 Sidney，和 Akron 被执行，美国与三次在在盖子庄稼结束的 2012-2013 的土壤采样，种的小麦，和小麦成熟。实验包括了四单个种类的盖子庄稼， 10 种类混合物，和一个休闲处理。测量的变量是土壤 C 和氮(N) ，由甲基酉旨(名声) 介绍的丰满的酸的土壤社区结构，和土壤 -glucosidase,-glucosaminidase, 和 phosphodiesterase 活动。休闲处理，缺乏生活植物，在盖子庄稼结束减少了大多数名声的集中。全部的名声集中与盖子庄稼生物资源被相关(R = 0.62 在 Sidney 并且 0.44 在 Akron ) 。等到种的小麦，有灌溉的有益的效果，它在 mycorrhizal 和原生动物门标记引起了增加。在小麦成熟，土壤名声上的盖子庄稼和灌溉效果减退了，但是灌溉在 Akron 在 -glucosidase 和 phosphodiesterase 活动上有积极效果，它二个地点中是更干燥的。盖子庄稼和灌溉是慢的影响土壤 C 集中。我们的结果证明盖子庄稼在在半干旱的基于小麦的旋转和灌溉的微生物引起的社区能提高的土壤上有短命效果土壤酶活动。在半干旱的环境，更长的时间跨度可能被需要在土壤上看见盖子庄稼的有益的效果微生物引起的社区结构，土壤酶活动，和土壤 C 隐遁。
Cover crops can have beneficial effects on soil microbiology by increasing carbon （C） supply, but these beneficial effects can be modulated by precipitation conditions. The objective of this study was to compare a fallow-winter wheat （Triticum aestivum L.） rotation to several cover crop-winter wheat rotations under rainfed and irrigated conditions in the semiarid US High Plains. Experiments were carried out at two sites, Sidney in Nebraska, and Akron in Colorado, USA, with three times of soil sampling in 2012--2013 at cover crop termination, wheat planting, and wheat maturity. The experiments included four single-species cover crops, a 10-species mixture, and a fallow treatment. The variables measured were soil C and nitrogen （N）, soil community structure by fatty acid methyl ester （FAME） profiles, and soil β-glucosidase,β-glucosaminidase, and phosphodiesterase activities. The fallow treatment, devoid of living plants, reduced the concentrations of most FAMEs at cover crop termination. The total FAME concentration was correlated with cover crop biomass （R = 0.62 at Sidney and 0.44 at Akron）. By the time of wheat planting, there was a beneficial effect of irrigation, which caused an increase in myeorrhizal and protozoan markers. At wheat maturity, the cover crop and irrigation effects on soil FAMEs had subsided, but irrigation had a positive effect on the β-glucosidase and phosphodiesterase activities at Akron, which was the drier of the two sites. Cover crops and irrigation were slow to impact soil C concentration. Our results show that cover crops had a short-lived effect on soil microbial communities in semiarid wheat-based rotations and irrigation could enhance soil enzyme activity. In the semiarid environment, longer time spans may have been needed to see beneficial effects of cover crops on soil microbial community structure, soil enzyme activities, and soil C sequestration.
