摘要：

为探讨绿肥种植对盐碱地淡水淋盐下土壤及淋溶液碳氮含量的影响,于2021年10月至2022年5月设置冬闲(T1)、冬牧70黑麦(T2)和油菜(T3)3个处理进行大田试验,测定土壤及淋溶液有机碳(SOC)、硝态氮($\mathrm{NO}_{3}{ }^{-}-\mathrm{N}$)、铵态氮($\mathrm{NH}_{4}^{+}-\mathrm{N}$)空间分布情况。结果表明,T1、T2、T3处理0~30 cm土层中土壤有机碳分别由淋盐前的6.20,6.58,7.24 g/kg增加到淋盐后的6.48,7.39,8.06 g/kg,增幅分别为4.41%,12.20%,11.23%。淋盐前后0~60 cm土层中T1处理土壤硝态氮含量显著高于T2和T3,淡水淋盐后,0~30 cm土层各处理分别降低42.42%,3.85%,10.84%;60~90 cm土层中减少了1.38%,7.96%,18.11%。淋盐前各土层土壤铵态氮含量不同处理之间无显著差异,淋盐后各土层土壤铵态氮含量均以T2含量最高。综上,淋盐灌溉后,相较于淋盐前各处理不同土层土壤有机碳均呈增加趋势,而土壤氮素则呈明显降低趋势,通过对土壤及淋溶液氮素含量分析发现,淋盐灌溉造成的氮素淋失主要以硝态氮为主。相较于冬闲田,种植油菜绿肥对土壤氮素提高有明显效果,而种植冬牧70绿肥对减少土壤氮素淋失具有最佳效果。

关键词: 盐碱地, 冬闲农田, 绿肥, 淡水淋盐, 有机碳, 硝态氮, 铵态氮

Abstract:

To investigate the influence of green manure cultivation on the carbon and nitrogen content of saline-alkali soil under freshwater leaching,a field experiment was conducted from October 2021 to May 2022.Three treatments were set up:winter fallow(T1),Dongmu 70 rye(T2),and rape(T3).The spatial distribution of soil organic carbon(SOC),nitrate nitrogen($\mathrm{NO}_{3}{ }^{-}-\mathrm{N}$),and ammonium nitrogen($\mathrm{NH}_{4}^{+}-\mathrm{N}$)in the soil and leachate were measured.The results revealed that in the 0—30 cm soil layer,the soil organic carbon content of T1,T2,and T3 increased from 6.20,6.58,7.24 g/kg before leaching to 6.48,7.39,8.06 g/kg after leaching,representing an increase of 4.41%,12.20%,and 11.23%,respectively.After freshwater leaching,the nitrate nitrogen content in the 0—60 cm soil layer of T1 was significantly higher than that of T2 and T3.In the 0—30 cm soil layer,the respective reductions for each treatment were 42.42%,3.85%,and 10.84%.In the 60—90 cm soil layer,the reductions were 1.38%,7.96% and 18.11%.There were no significant differences in ammonium nitrogen content among the different treatments before leaching,but after leaching,the highest ammonium nitrogen content was observed in T2.In conclusion,after leaching irrigation,the soil organic carbon content in different soil layers increased compared to before leaching,while soil nitrogen showed a significant decrease.Analysis of nitrogen content in the soil and leachate indicated that the main nitrogen loss caused by leaching irrigation was in the form of nitrate nitrogen.Compared to winter fallow farmland,the cultivation of rapeseed green manure had a significant effect on increasing soil nitrogen content,while Dongmu 70 green manure was the the most effective in reducing soil nitrogen loss.

Key words: Saline-alkali land, Winter fallow farmland, Green manure, Freshwater pillar salt, Organic carbon, Nitrate nitrogen, Ammonium nitrogen