山东省冬闲农田种植冬牧70压青后腐解及养分动态

Dynamics of Nutrients and Decomposition of Dongmu 70 Cultivated in Winter Fallow Period in Shandong Province

为研究冬闲农田种植绿肥翻压后的腐解及土壤养分释放动态,利用网袋法分别在青岛胶州、青岛平度、东营利津对冬牧70进行原位腐解试验,前茬作物皆为玉米,后茬分别种植马铃薯、花生、棉花,种植前将冬牧70粉碎后翻耕。在翻压后10、20、40、60、80、100、110d取样测定其干物质量及养分含量,计算其腐解剩余率、N、P、K、C的累计释放率、碳氮比等指标。结果表明,三地冬牧70都呈现指数腐解动态,在翻压前期腐解速度较快,40 d后降低。经过110 d的腐解,胶州、平度、利津腐解剩余率分别为21.33%、20.58%、18.09%;N累计释放率分别为90.11%、73.61%、81.99%;P累计释放率分别为85.82%、80.71%、83.59%;K累计释放率分别为99.55%、99.78%、99.87%,C累计释放率分别为87.78%、81.39%、83.00%,各养分的累计释放率表现为钾>氮>碳>磷,钾素累计释放量较大且速度较快。随腐解时间的延长碳氮比不断降低,经过110 d的腐解,胶州、平度、利津三地碳氮比分别降低到25.40%、15.99%、24.48%。试验结果对于了解不同土壤类型绿肥分解速度和养分释放量动态,合理运筹肥料以避免绿肥翻压与作物养分需求产生矛盾有重要的指导意义;同时为促进冬闲农田绿肥种植推广,改善土壤生态环境具有重要的参考价值。

The nylon-bag method was used to study the in-situ decomposition and release of nutrients of Dongmu 70 in Jiaozhou,Pingdu,Qingdao city and Lijin,Dongying city,respectively.The potato,peanut and cotton were planted after corn in these zone and Dongmu 70 was crushed and ploughed before cultivating.The accumulative releasing rate of N,P,K and C,and residual percent after decomposition of 10,20,40,60,80,100 and 110 days for Dongmu 70 were investigated,respectively.The results showed that exponential dynamics decomposition of Dongmu 70 was found in these experiments,and it decomposed fast in the primary stage of decomposition and then the decomposition rate decreased in 40 days.The decomposition residual rates of Dongmu 70 were 21.33%,20.58%,and 18.09%,after 110 days of decomposition,respectively.Moreover,the accumulative releasing rates of N were 90.11%,73.61%,81.99%,respectively.However,the accumulative releasing rates of P were 85.82%,80.71%and 83.59%,respectively.The accumulative releasing rates of K were 99.55%,99.78%and 99.87%,respectively.The cumulative release rates of carbon were 87.78%,81.39%,83.00%,respectively.The cumulative release rates of nutrients showed as follows:K>N>C>P,and potassium released high and fast.The C/N decreased with the decomposition process.After 110 days of decomposition,the C/N decreased to 25.40%,15.99%and 24.48%in Jiaozhou,Pingdu and Lijin,respectively.The results are important to know decomposition rate of green manure and dynamic of nutrient release in different types of soils,and is also valuable for fertilizer,green manure and crop management in order to avoid a conflict of nutrients.At the same time,it can promote the promotion of green manure planting in winter idle farmland,the results are valuable for improving cultivating green manure in winter fallow period and soil ecology and environment.