田菁翻压还田对滩涂土壤碳氮及微生物生物量的影响

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

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。

A field experiment was conducted to explore the effects of overturning Sesbania cannabina on the improvement of soil in coastal area, the biomass, carbon and nitrogen contents of Sesbania cannabina under different fertilization treatments(CK, N 0 kg/hm^(2);SN1, N 90 kg/hm^(2);SN2, N 135 kg/hm^(2);SN3, N 180 kg/hm^(2);SN4, N 225 kg/hm^(2);SN4+OF, N 225 kg/hm^(2) +organic fertilizer), microbiological biomass, carbon and nitrogen contents of soil were determined, and the correlations between soil properties and plant indexes were analyzed. The results showed that SN3 got the highest total biomass, and nitrogen and carbon contents in twice mowing of Sesbania cannabina. SN4 + OF had the highest contents of soil organic carbon, total nitrogen and fixed ammonium, which were 6.44 g/kg, 0.62 g/kg and 40.1 mg/kg, respectively. SN2 had the highest contents of active organic carbon, nitrate nitrogen, ammonium nitrogen, microbial biomass carbon(MBC) and nitrogen(MBN) and CPMI. SN4 + OF and SN2 got the highest ratios of soil C/N and MBC/MBN. In conclusion, SN3 can significantly increase the biomass, carbon and nitrogen contents of Sesbania cannabina, and SN2 and SN4+OF have the better effect on soil improvement.