Zhao Yi, Wang Yuqiang, Sun Shengnan, Liu Wentao, Zhu Ling, Yan Xuebing
College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China.
Joint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou 225009, China.
Plants (Basel). 2022 Apr 13;11(8):1057. doi: 10.3390/plants11081057.
Nitrogen fertilization is a simple and effective field management strategy for increasing plant productivity, but the regulatory mechanisms of nitrogen forms and proportions on soil nutrients and plant growth remain unclear. Therefore, we investigated soil enzyme activities and nutrient contents of alfalfa under different forms and proportions of exogenous nitrogen addition. Results showed that nitrogen input significantly increased the activity of three oxidoreductases (hydroxylamine reductase, nitrate reductase, and nitrite reductase) while having no significant effects on urease. A high proportion of ammonium nitrogen significantly increased neutral protease activity. The amylase activity markedly increased under mixed-nitrogen addition but decreased under single-nitrogen addition. Additionally, the contents of soil nutrients (soil organic matter, total nitrogen, nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium) were significantly increased under different exogenous nitrogen inputs, which drove the changes in enzyme activities. Further, nitrogen addition also improved the biomass and nitrogen content of alfalfa. These findings indicated that applying different forms and proportions of exogenous nitrogen may stimulate soil enzyme activities, which will accelerate the transformation of nutrients and then promote alfalfa growth.
氮肥施用是提高植物生产力的一种简单有效的田间管理策略，但氮素形态和比例对土壤养分及植物生长的调控机制仍不清楚。因此，我们研究了不同形态和比例外源氮添加条件下苜蓿的土壤酶活性和养分含量。结果表明，氮输入显著提高了三种氧化还原酶（羟胺还原酶、硝酸还原酶和亚硝酸还原酶）的活性，而对脲酶无显著影响。高比例铵态氮显著提高了中性蛋白酶活性。混合氮添加下淀粉酶活性显著增加，单氮添加下淀粉酶活性降低。此外，不同外源氮输入下土壤养分（土壤有机质、全氮、硝态氮、铵态氮、有效磷和速效钾）含量显著增加，这推动了酶活性的变化。此外，施氮还提高了苜蓿的生物量和氮含量。这些结果表明，施用不同形态和比例的外源氮可能刺激土壤酶活性，从而加速养分转化，进而促进苜蓿生长。
