施用生物炭对东台沿海杨树人工林土壤理化性质及酶活性的影响

Effects of biochar application on soil physicochemical properties and enzyme activities in poplar plantation in Dongtai coastal area

以东台杨树人工林为研究对象,开展野外试验,设置了4个水平生物炭处理:低施用量(40 t·hm^-2)、中施用量(80 t·hm^-2)、高施用量(120 t·hm^-2)及对照(0 t·hm^-2),对土壤蛋白酶、脲酶和蔗糖酶的活性进行一年的动态测定;同时测定了土壤理化指标,以分析土壤酶活性的变化及与理化性质间的相关性.结果表明:施用生物炭可以提高土壤pH值、全碳、有机碳及NH+4含量,降低土壤容重和含水率;中、高生物炭施用量提高了土壤全氮、NO3^-含量,低施用量则反之.3个水平的施用量都降低了土壤蛋白酶和脲酶的活性;低施用量下蔗糖酶的活性降低,但是中、高施用量下蔗糖酶的活性升高.总体来说,施用生物炭会降低土壤酶指标,并且随着施用量的升高,土壤酶指数逐渐降低.

To study the effects of biochar on the structure and function of soil ecosystem, 4 levels of biochar(0, 40, 80 and 120 t·hm-2) were set up in poplar plantation in Dongtai Forest Center in Jiangsu Province, with each treatment replicated for 4 times. Activities of soil protease, urease and invertase were measured dynamically for one year together with soil physical and chemical indicators. The correlations between soil physiochemical properties and enzyme activities were further analyzed. The results showed that application of biochar generally increased soil pH values, contents of total carbon, organic carbon and NH+4, and lowered soil bulk density and water content. Biochar applied at 80 and 120 t·hm^-2 increased soil total nitrogen and NO3^- contents while the application at 40 t·hm^-2 lowered the contents. Soil protease and urease activities were both inhibited at 3 levels of applications. Invertase activities were promoted when applying biochar at 80 and 120 t·hm^-2 though the activities were reduced at the lowest application. Soil enzyme index declined with the supplements of biochar, and the higher rate applied, the bigger decline soil enzyme index became.