土壤活性氮动态变化及氮素可利用性对紫云英翻压量的响应

程会丹; 鲁艳红; 聂军; 朱启东; 聂鑫; 曹卫东; 高雅洁; 廖育林

文章摘要

土壤活性氮动态变化及氮素可利用性对紫云英翻压量的响应

Effect of application rate of Chinese milk vetch on soil active nitrogen dynamics and nitrogen availability

投稿时间：2020-05-14

DOI：10.13254/j.jare.2020.0250

中文关键词: 紫云英，无机氮，微生物量氮，可溶性有机氮，氮素利用性

英文关键词: Chinese milk vetch, inorganic nitrogen, microbial biomass nitrogen, dissolved organic nitrogen, nitrogen availability

基金项目:国家重点研发计划（2017YFD0301504，2018YFD03006）；国家绿肥产业技术体系（CARS-22-G-11）；湖南省农业科技创新资金项目（2018ZD02-2，2019LS03-1）

作者	单位	E-mail
程会丹	湖南省土壤肥料研究所, 长沙 410125 湖南大学研究生院隆平分院, 长沙 410125
鲁艳红	湖南省土壤肥料研究所, 长沙 410125 农业农村部湖南耕地保育科学观测实验站, 长沙 410125
聂军	湖南省土壤肥料研究所, 长沙 410125 湖南大学研究生院隆平分院, 长沙 410125 农业农村部湖南耕地保育科学观测实验站, 长沙 410125
朱启东	湖南省土壤肥料研究所, 长沙 410125 农业农村部湖南耕地保育科学观测实验站, 长沙 410125
聂鑫	湖南省土壤肥料研究所, 长沙 410125 湖南大学研究生院隆平分院, 长沙 410125
曹卫东	中国农业科学院农业资源与农业区划研究所, 北京 100081
高雅洁	湖南省土壤肥料研究所, 长沙 410125 农业农村部湖南耕地保育科学观测实验站, 长沙 410125
廖育林	湖南省土壤肥料研究所, 长沙 410125 湖南大学研究生院隆平分院, 长沙 410125 农业农村部湖南耕地保育科学观测实验站, 长沙 410125	ylliao2006@126.com

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中文摘要:

通过田间定位试验，研究了减量化肥紫云英不同翻压量下土壤活性氮的含量、动态变化及氮素可利用性，探讨了紫云英鲜草的适宜翻压量和土壤氮素利用效率，为双季稻合理施用氮肥提供理论依据。在稻-稻-紫云英轮作体系典型时期紫云英翻压前、早稻分蘖盛期、早稻成熟期、晚稻分蘖盛期、晚稻成熟期分别采集土壤样品，监测稻田土壤微生物量氮（MBN）、可溶性有机氮（DON）含量动态变化及氮素可利用性，并分析晚稻成熟期土壤铵态氮（NH₄⁺-N）和硝态氮（NO₃^--N）含量。结果表明：与对照（CK）处理相比，各施肥处理均提高了土壤全氮（TN）、NH₄⁺-N和NO₃^--N含量，增幅分别为10.4%~21.2%、10.3%~44.1%和14.7%~52.9%。在翻压紫云英15.0~22.5 t·hm^-2时，土壤TN、NH₄⁺-N和NO₃^--N含量均随紫云英还田量增多而提高，之后则随还田量的增多而降低。与常规施肥处理相比，化肥减施下紫云英各翻压量处理均提高了土壤MBN、DON及活性氮含量，增幅分别为7.0%~28.7%、8.5%~22.5%和5.8%~26.6%，且随紫云英翻压量的增加呈先增加后降低的变化趋势，MBN和活性氮含量均在翻压量22.5 t·hm^-2时最高，DON含量在翻压量30.0 t·hm^-2时最高。MBN/TN在翻压量22.5 t·hm^-2时最高，DON/TN在翻压量30.0 t·hm^-2时最高。各处理不同时期土壤MBN、DON含量及MBN/TN、DON/TN有明显波动，总体来看，土壤MBN含量及MBN/TN在早稻分蘖盛期明显降低，早稻成熟期有所回升，至晚稻成熟期又逐渐降低；土壤DON含量及DON/TN在早稻成熟期降至最低，至晚稻成熟期再次上升。研究表明，减施40%化肥条件下长期翻压紫云英不仅能增加土壤活性氮含量，同时有利于提高土壤氮素可利用性，紫云英翻压量22.5~30.0 t·hm^-2时效果最好。

英文摘要:

A located field experiment was conducted to investigate, dynamic change of the soil active nitrogen concentration, and nitrogen availability under application of reduced chemical fertilizer combined with Chinese milk vetch. Another aim was to explore the optimal application rate of Chinese milk vetch fresh grass and nitrogen utilization efficiency, thus providing theoretical basis for the rational application of nitrogen fertilizer in double cropping paddy soil. Soil samples were collected in the typical period of rice-rice-Chinese milk vetch rotation, i.e., before the incorporation of Chinese milk vetch(S1), tillering stage of early rice(S2), mature stage of early rice(S3), tillering stage of late rice(S4), and mature stage of late rice(S5). The samples were analyzed for the dynamic changes in soil microbial biomass nitrogen(MBN), dissolved organic nitrogen(DON), and nitrogen availability. The concentrations of NH4+-N and NO- 3-N in the soil at the mature stage of late rice were also analyzed. The results showed that compared with CK treatment, each fertilization treatment led to an increase in the concentration of soil total nitrogen(TN), ammonia nitrogen(NH4+-N), and nitrate nitrogen(NO- 3-N), with an increase of 10.4%~21.2%, 10.3%~44.1%, and 14.7%~52.9%, respectively. The concentrations increased with the amount of Chinese milk vetch applied(15.0~22.5 t·hm^-2), but showed a decreasing trend when the applied amount was over 22.5 t·hm^-2. Compared with the conventional fertilization, the application of reduced chemical fertilizer combined with Chinese milk vetch led to an increase in the contents of soil MBN, DON, and active nitrogen, with an increase of 7.0%~28.7%, 8.5%~22.5%, and 5.8%~26.6%, respectively. The concentrations of MBN, DON, and active nitrogen increased first and then decreased with the increase in the amount of Chinese milk vetch. The content of both MBN and active nitrogen was highest at 22.5 t·hm^-2 of Chinese milk vetch, while that of DON was highest at 30.0 t·hm^-2 of Chinese milk vetch. The ratio of MBN to TN was highest at 22.5 t·hm^-2 of Chinese milk vetch, whereas that of DON to TN was highest at 30.0 t·hm^-2 of Chinese milk vetch. The concentrations of MBN and DON in soil and the ratios of MBN to TN and DON to TN fluctuated significantly between different periods of the same treatment. In general, the soil MBN concentration and the ratio of MBN to TN decreased significantly in the tillering stage of early rice, rebounded in the mature stage of early rice, and gradually decreased in the mature stage of late rice. The soil DON concentration and the ratio of DON to TN decreased to the lowest level in the mature stage of early rice, and then increased again in the mature stage of late rice stage. Comprehensively, the long-term cultivation of Chinese milk vetch under 40% reduced chemical fertilization can not only increase the soil active nitrogen concentration, but also improve the soil nitrogen availability. Moreover, the optimal application rate of Chinese milk vetch is recommended as 22.5~30.0 t·hm^-2.

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