腐解菌剂对红壤橘园圆叶决明腐解及养分释放动态的影响

Effects of Decomposing Microbial Inoculum on Decomposition and Nutrient Release Dynamics of Chamaecrista rotundifolia in Red Soil of Orange Orchards

为明确绿肥配施腐解菌剂在红壤旱地中的腐解及养分释放规律,更好地利用其营养,在田间条件下,设置对照(CK)、腐解菌剂(DM)、腐解菌剂+炭基有机肥(BM)和腐解菌剂+固氮菌(NM)4个处理,采用尼龙网袋法模拟研究圆叶决明在橘园红壤中的腐解及养分释放动态特征,并测定其养分残留率。结果表明,夏季绿肥圆叶决明中有机物腐解和养分释放在翻压后前2周速率最快,之后逐渐变缓。绿肥秸秆翻压后前10天平均每天的腐解速率为3.319 g/d,碳、氮、磷、钾平均每天的释放速率分别为1.765、0.124、0.009、0.090 g/d;第10~70天平均每天的腐解速率为0.531 g/d,碳、氮、磷、钾平均每天的释放速率分别为0.230、0.014、0.002、0.007 g/d。绿肥翻压后第70天,CK、DM、BM和NM处理秸秆质量累计减少率分别达到67.96%、73.72%、79.73%和76.68%,碳累计释放率分别为70.07%、76.84%、85.07%和77.70%,氮累计释放率分别为78.00%、82.20%、85.34%和83.81%,磷累计释放率分别为81.27%、84.85%、91.74%和85.08%,钾累计释放率分别为97.58%、98.39%、98.45%和98.36%。不同处理下圆叶决明秸秆养分释放率均表现为钾>磷>氮>碳。其中,以BM处理秸秆腐解及养分释放率最快。综合考虑绿肥腐解及养分释放规律,夏季绿肥圆叶决明配施腐解菌剂后翻压能有效改善旱地红壤微生物结构,提高腐解速率,增加养分释放效率。

To clarify the decomposition and nutrient release of green manure combined with microbial inoculum in arid red soil,and to make better use of the nutrients,under field conditions,four treatments were conducted including control(CK),decomposing microbial inoculum(DM),decomposing microbial inoculum+biochar organic fertilizer(BM),and decomposing microbial inoculum+nitrogen-fixing bacteria(NM).The dynamic characteristics of decomposing and nutrient release of Chamaecrista rotundifolia in arid red soil of orange orchard were simulated by nylon-bag method,and the nutrient residual rate was also determined.The results showed that the rate of organic matter decomposition and nutrient release were the fastest in the first two weeks after turnover,and then decreased gradually.Ten days after turnover,the average daily decomposition rate of green manure straw was 3.319 g/d,and the average daily release rate of C,N,P and K was 1.765,0.124,0.009 and 0.090 g/d,respectively.The average daily decomposition rate of green manure straw from the 10 thto70 thday after turnover was 0.531 g/d,and the average daily release rate of C,N,P and K was 0.230,0.014,0.002 and 0.007 g/d,respectively.On the 70 thday of the decomposition of green manure,the cumulative reduction rate of straw mass treated by CK,DM,BM and NM treatment was 67.96%,73.72%,79.73%and76.68%,respectively;and the cumulative release rate of C under the four treatments was 70.07%,76.84%,85.07%and 77.70%,respectively;the cumulative release rate of N was 78.00%,82.20%,85.34%and 83.81%,respectively;the cumulative release rate of P was 81.27%,84.85%,91.74%and 85.08%,respectively;the cumulative release rate of K was 97.58%,98.39%,98.45%and 98.36%,respectively.The nutrient release rate of straw of Chamaecrista rotundifolia under different treatments was in the range of K>P>N>C,and BM treatment had the fastest rate of decomposition and nutrient release.Considering the decomposition of green manure and nutrient release comprehensively,the application of decomposing microbial inoculum in combination with Chamaecrista rotundifolia and turnover could effectively improve the soil microbial structure,increase the rate of decomposition and the efficiency of nutrient release in arid red soil.