Davies Benjamin, Coulter Jeffrey A, Pagliari Paulo H
Famine Early Warning Systems Network, Washington, DC 20003, USA.
Department of Agronomy and Plant Genetics, University of Minnesota, Saint Paul, MN 55108, USA.
Plants (Basel). 2022 Aug 29;11(17):2247. doi: 10.3390/plants11172247.
Understanding how fertilizer application (particularly N, the most used chemical fertilizer worldwide) interacts with soil microbes is important for the development of best management practices that target improved microbial activity to enhance sustainable food production. This study was conducted to determine whether urea N rate and time of application to maize () influenced soil enzyme activity. Enzyme activity was determined by monitoring fluorescein diacetate (FDA) hydrolysis, ß-glucosidase, acid-phosphomonoesterase, and arylsulfatase activities. Experiments were conducted from 2014 through 2016 to compare single (fall or spring applications) and split applications of N at varying N rates under irrigation (Becker) and rainfed conditions (Lamberton and Waseca) in MN, USA. Nitrogen rates varied by location and were based on University of Minnesota guidelines. Soil samples were collected seven times each season. Nitrogen application split into two applications increased FDA activity by 10% compared with fall and spring applied N at Waseca. Fall or spring N application decreased arylsulfatase activity by 19% at Becker and by between 13% and 16% at Lamberton. ß-Glucosidase and acid-phosphomonoesterase activities were unaffected by N application. Sampling time and year had the greatest impact on enzyme activity, but the results varied by location. A negative linear relationship occurred between FDA and ß-glucosidase activity at all three sites. In summary, urea N application had small effects on enzyme activity at the sites studied, suggesting that some form of organic N could be more important than the ammonium provided by urea.
了解肥料施用（特别是全球使用最广泛的化学肥料氮）如何与土壤微生物相互作用，对于制定最佳管理措施至关重要，这些措施旨在提高微生物活性以促进可持续粮食生产。本研究旨在确定玉米的尿素施氮量和施肥时间是否会影响土壤酶活性。通过监测荧光素二乙酸酯（FDA）水解、β-葡萄糖苷酶、酸性磷酸单酯酶和芳基硫酸酯酶的活性来测定酶活性。2014年至2016年进行了实验，以比较美国明尼苏达州灌溉条件下（贝克尔）和雨养条件下（兰伯顿和瓦西卡）不同施氮量的单次（秋季或春季施肥）和分次施肥情况。施氮量因地点而异，依据明尼苏达大学的指导方针确定。每个季节采集七次土壤样本。与在瓦西卡秋季和春季施氮相比，分次施氮使FDA活性提高了10%。在贝克尔，秋季或春季施氮使芳基硫酸酯酶活性降低了19%，在兰伯顿降低了13%至16%。β-葡萄糖苷酶和酸性磷酸单酯酶的活性不受施氮影响。采样时间和年份对酶活性影响最大，但结果因地点而异。在所有三个地点，FDA与β-葡萄糖苷酶活性之间均呈负线性关系。总之，在所研究的地点，尿素施氮对酶活性影响较小，这表明某种形式的有机氮可能比尿素提供的铵更重要。
