土壤不同形态碳氮含量和酶活性对培养时间及外源碳投入的响应

Responses of Different Forms of Soil Carbon and Nitrogen Contents and Enzyme Activities to Cultivation Time and Exogenous Carbon Input

在绿色农业科技的推动下,有机物料资源化利用备受青睐,但有机物料种类不同对土壤肥力的提升效果不同,为探究有机物料施用对潮土不同形态碳氮含量及酶活性的动态影响,通过为期1年的培养试验,设置添加10 g/kg的秸秆菌渣(S)、树枝菌渣(B)、小麦秸秆(W)、黑麦草秸秆(R)和蚕豆秸秆(BB),并以空白处理作为对照(CK)。结果表明:与CK相比,有机物料施用显著增加土壤不同形态碳氮含量及酶活性,随培养时间的延长,有机碳及全氮含量呈增加的趋势,增幅分别为25.4%~42.9%和35%~60%,易氧化有机碳和碱解氮含量呈先上升后下降的趋势,最大值分别为2.80,43.26 mg/kg,水溶性有机碳、微生物量碳氮和酶活性则呈下降的趋势,最大值分别为346 mg/kg,293μg/g和23.08μg/g。有机物料施用会增加土壤酶活性提高土壤呼吸速率,通过对3个取样期7种水解酶的分析发现,酶活性表现为:LAP>PHOS>NAG>BG>CB>AG>XYL,即参与氮循环酶活性>参与磷循环酶活性>参与碳循环酶活性,绿肥秸秆主要增加氮循环酶活性,且以BB处理酶活性最高,菌菇渣主要增加碳循环酶活性,B处理酶活性高于S处理。有机物料施用会影响土壤酶活性,增加不同形态碳氮含量,但增幅因有机物料种类不同而有所差异,且碳氮组分对培养时间的响应不一。总体而言,小麦秸秆和蚕豆秸秆腐殖化系数最高,对不同组分碳氮含量增加效果最优。

With the promotion of green agricultural technology,the utilization of organic materials has been favored,but different types of organic materials have different effects on improving soil fertility.In order to explore the dynamic effect of organic materials application on the content of carbon and nitrogen in different forms and the enzyme activity in alluvial soil,a one-year culture test was conducted with treatments including add 10 g/kg of straw fungus residue(S),dendritic fungus residue(B),wheat straw(W),ryegrass straw(R),broad bean straw(BB),and Control(CK).The results showed that compared with CK,the application of organic materials significantly increased the carbon and nitrogen content in different forms and enzyme activity in soil.With the increase of the cultivation time,the organic matter and total nitrogen content showed increase trends with increases of 25.4%to 42.9%and 35%to 60%,respectively.The contents of easily oxidizable organic carbon and alkali-hydrolyzable nitrogen increased first and then decreased,and maximized at 2.80 and 43.26 mg/kg.Organic carbon,microbial biomass carbon and nitrogen,and enzyme activity showed a downward trend with the maximum values were 346 mg/kg,293μg/g,and 23.08μg/g.Organic material application could increase soil respiration rate by increasing soil enzyme activity.Through analysis of 7 hydrolytic enzymes at three sampling periods,the enzyme activity was:LAP>PHOS>NAG>BG>CB>AG>XYL,which indicating enzyme activity in the nitrogen cycle>enzyme activity in phosphorus cycle>enzyme activity in carbon cycle.Green manure straw mainly increased nitrogen cycle enzyme activity,and BB treatment had the highest enzyme activity.Mushroom residue mainly increased carbon cycle enzyme activity,the treatment activity of B was higher than that of S.Organic material application will affect soil enzyme activity and increase the content of different forms of carbon and nitrogen,but the increase varies depending on the types of organic material,and the response of the carbon and nitrogen components to the culture time is different.In general,wheat straw and broad bean straw showed the highest humification coefficient,and had the best effect on increasing the carbon and nitrogen content of different components.