不同轮作模式下氮肥用量对土壤有机氮组分的影响

发布时间：2019-04-11 17:51

【摘要】：通过三年六季的田间定位试验,对比研究了水旱轮作(水稻/油菜)和旱地轮作(棉花/油菜)下氮肥用量对土壤有机氮含量及其组分的影响。结果表明,经过三年轮作后,周年轮作氮肥投入超过300 kg hm~(-2)(以纯氮计,下同)的处理0~20 cm土壤全氮含量明显增加。与不施氮处理相比,周年氮肥用量为300 kg hm~(-2)和375 kg hm~(-2)水旱轮作处理0~20 cm土壤全氮含量增加了13.6%~23.5%,而旱地轮作处理则增加了15.0%~23.0%,土壤酸解态氮含量增加是土壤全氮变化的主要原因。两种轮作模式下土壤酸解态氮含量无显著差异,但土壤酸解态氮各组分的变化却不相同。水旱轮作中酸解铵态氮增加的比例(33.8%)低于旱地轮作(53.9%),但其酸解未知态氮含量增加的比例(36.0%)高于旱地轮作(16.6%)。综上所述,周年氮肥合理施用能明显提高土壤有机氮含量,水旱和旱地轮作下土壤酸解态氮库各组分变化差异明显。根据不同轮作模式下土壤有机氮库转化特点,优化氮肥施用对于提高作物产量和氮肥利用率具有重要意义。
[Abstract]:A three-year and six-season field experiment was conducted to compare the effects of nitrogen application rate on soil organic nitrogen content and its components under paddy-dry rotation (rice / rape) and dry-land rotation (cotton / rape). The results showed that after three years' rotation, the soil total nitrogen content of 0 ~ 20 kg hm~ (- 2) (pure nitrogen) treatment with annual rotation nitrogen input more than 300 cm (- 2) increased significantly. Compared with the non-nitrogen treatment, the annual nitrogen application rate of 300 kg hm~ (- 2) and 375 kg hm~ (- 2) increased 13.6% ~ 23.5% of soil total nitrogen content in 0 / 20 cm and 15.0% / 23.0% in dryland rotation treatment, respectively, while the annual nitrogen application rate of 300 cm (- 2) and 375 kg hm~ (- 2) increased by 13.6% ~ 23.5% and 15.0% / 23.5% respectively. The increase of soil acid-hydrolyzed nitrogen content is the main reason for the change of soil total nitrogen. There was no significant difference in the content of acid-hydrolyzed nitrogen between the two rotation models, but the changes of the components of soil-hydrolyzed nitrogen were not the same. The percentage of acid-hydrolyzed ammonium nitrogen increased in paddy-dry rotation (33.8%) was lower than that in dry-land rotation (53.9%), but the increase in acid-hydrolyzed unknown nitrogen content (36.0%) was higher than that in dry-land rotation (16.6%). In conclusion, rational application of annual nitrogen fertilizer can obviously increase the content of soil organic nitrogen, and the variation of the components of soil acidified nitrogen pool under the rotation of paddy and dry land is obvious. According to the characteristics of soil organic nitrogen pool transformation under different rotation patterns, it is of great significance to improve crop yield and nitrogen use efficiency by optimizing nitrogen fertilizer application.
【作者单位】：华中农业大学资源与环境学院农业部长江中下游耕地保育重点实验室;
【基金】：国家自然科学基金项目(41401324) 国家油菜产业技术体系建设专项(CARS-13)资助~~
【分类号】：S153.62

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