施用秸秆对土壤可溶性有机碳氮及矿质氮的影响

Effects of Addition Amounts of Straw on Soil Dissolved Organic Carbon,Nitrogen and Mineral Nitrogen

为了研究施用秸秆对土壤可溶性有机碳氮及矿质态氮含量的影响,设置CK(对照),M2,M4,M6共4个处理,处理中每100g干土中加入秸秆量分别为0,2,4,6g。在室温为25℃、土壤含水量为田间持水量的70%的条件下进行培养试验,分别在15,30,45,60,105,150d时,采取各处理中的土壤样品,观测土壤可溶性有机碳氮及矿质氮的动态变化。结果表明:4个处理的土壤可溶性有机碳、氮具有相同的变化趋势,表现为随着培养时间的推移,先增加,再减小,然后经过一段时间的波动后趋于平稳。在培养的整个过程中,M4与M6处理的土壤可溶性有机碳、氮明显高于CK中的含量,表明了施用秸秆可以促进土壤可溶性有机碳氮的累积。在相同时间段内,各处理之间铵态氮含量无明显差异,与对照相比,加入秸秆后,土壤中硝态氮的含量明显下降。

In order to examine the effects of straw amendment on soil dissolved organic carbon, nitrogen and mineral nitrogen, 4 treatments were set up, which included CK （no straw）, M2 （2 g of straw in 100 g soil）, M4 （4 g of straw in 100 g soil） and M6 （6 g of straw in 100 g soil）. The straw and soil were mixed evenly, the soil water was kept 70% of water holding capacity, then the incubation experiment was conducted at room temperature （25 ℃ ）, and soil moisture was controlled by weighing. Soil samples were taken in 15 d, 30 d, 45 d, 60 d, 105 d and 150 d, respectively. The results showed that the 4 treatments had the same change trend in terms of soil dissolved organic carbon（DOC） and dissolved organic nitrogen（DON）, upward trend was ob served at first, then DOC and DON went down, and leveled off after a period of fluctuation. The soil levels of DOC and DON of M4 and M6 treatments were significantly higher than CK. Ammonium nitrogen content had no obvious difference among all treatments in the same period. The contents of nitrate nitrogen signifi- cantly decreased after straw was added into soil compared with the CK.