田菁翻压还田对滩涂土壤碳氮及微生物生物量的影响

为探讨不同施肥处理下田菁翻压还田对滩涂土壤的改良效果,通过田间小区试验对不同施肥处理(CK、SN1、SN2、SN3、SN4及SN4+OF对应的施氮量分别为N 0、90、135、180、225 kg/hm~2及N 225 kg/hm~2+有机肥)下田菁生物量、碳氮养分含量及翻压还田对土壤碳氮、微生物生物量的影响及各指标间的相关性进行了研究。结果表明:SN3处理对提高田菁总生物量及两次刈割地上部碳氮含量效果明显。SN4+OF处理下田菁翻压还田后土壤有机碳、全氮及固定态铵含量明显提升,分别为6.44 g/kg、0.62 g/kg和40.1mg/kg,土壤活性有机碳、硝态氮、铵态氮、微生物生物量碳氮(MBC、MBN)含量及碳库管理指数(CPMI)均以SN2处理下田菁翻压还田效果较优。土壤C/N、MBC/MBN比值分别以SN4+OF和SN2处理下田菁翻压还田最高。因此,SN3处理可明显提高田菁生物量和碳氮养分含量,而田菁翻压还田效果则以SN2及SN4+OF处理较优。

Effects of Overturning Sesbania cannabina on Soil Carbon, Nitrogen and Microbiological Biomass in Coastal Area

In order to explore the effect of overturning and returning of Sesbania cannabina to fields on the improvement of soil in coastal area, field experiments were conducted to study the biomass, carbon and nitrogen nutrient content of Sesbania cannabina under different fertilization treatments (Control, SN1, SN2, SN3, SN4, SN4+OF), as well as the microbiological characteristics, carbon and nitrogen nutrients of soil in coastal area by overturning Sesbania cannabina. The correlations between the soil and plant indexes were also studied. It indicates that the SN3 treatment got the highest total biomass and total nitrogen content in the cutting part and shoots of Sesbania cannabina,as well as the content of organic carbon. By overturing of Sesbania cannabina, the highest contents of soil organic carbon, total nitrogen and fixed ammonium were appeared in SN4 + OF treatment, which were 6.44 g.kg_^-1, 0.62 g.kg_^-1and 40.1 g.kg_^-1, respectively. The carbon, nitrate nitrogen, ammonium nitrogen, microbial biomass carbon/nitrogen, and CPMI were significantly higher with SN2 treatment than other treatments. SN4 + OF and SN2 treatments got the highest values of soil C / N and MBC / MBN respectively. Therefore, SN3 treatment can significantly increase the biomass, carbon and nitrogen nutrient content of Sesbania cannabina, while the effect on soil improvement is better with SN2 and SN4+OF treatment by overturning and returning of Sesbania cannabina to field.