华北地区棉田翻压冬绿肥腐解及养分释放规律研究

Study on Regulars of Decompostion and Nutrients Releasing of Green Manure Ploughed in Cotton Field in North Plain of China

利用尼龙网袋,研究了油菜、毛叶苕子、冬牧70黑麦翻压于棉花田间15～20 cm土层,腐解及养分释放规律。研究表明,绿肥翻压43 d内干物重显著降低,前3 d腐解速度最快,后降低趋势变缓。翻压43 d时油菜、毛叶苕子、冬牧70黑麦腐解率达到81.7%,77.5%,62.2%;翻压113 d时腐解率分别达到89.6%,89.5%,76.2%。翻压21d内氮释放较快,3个品种氮矿化率都达到60%以上。磷在整个翻压期内释放较为平缓,翻压113 d时油菜、毛叶苕子、冬牧70黑麦磷矿化率分别达到89.6%,86.5%,75.6%。钾在翻压前期迅速释放,翻压9 d后,油菜、毛叶苕子、冬牧70黑麦钾的矿化率分别为94.5%,93.2%,91.9%。翻压前21 d,绿肥碳含量显著降低,以后逐渐缓慢,翻压113 d后油菜、毛叶苕子、冬牧70黑麦碳矿化率为93.4%,91.3%,81.9%。在翻压前15 d,冬牧70黑麦C/N呈上升趋势,其他两品种C/N变化不显著。

This experiment studied on the decay process and nutrition release regulars of green manure ploughed in cotton field（15-20 cm soil layer）and green manure were installed in nilong dilly bag.Green manure included winter 70 rye,winter rape,and hairy vetch.The results showed that：dry matter weight of green manure decreased significantly dring 0-43 days incubation,decomposing speed were most fast in the first three days,then more and more slowly.After 43 days incubation,decomposition rate of winter rape,hairy vetch and winter 70 rye at 81.7%,77.5%,62.2%,and after 113 days incubation at 89.6%,89.5%,76.2%,respectively.Nitrogen released fast in the first 21days,after 21 days incubation,N-mineralization rates of three green manure were all greater than 60%.Phosphorous released gently during the whole ploughing days,after 113 days incubation,P-mineralization rates of winter rape,hairy vetch and winter 70 rye at 89.6%,86.5%,75.6%,respectively.Potassium released fast in the first 9 days,K-mineralization rates were more than 90% after 9 days incubation.Carbon released fast in the first 21days,after 113 days incubation,C-mineralization rates of winter rape,hairy vetch and winter 70 rye at 93.4%,91.3%,81.9%,respectively.C/N ratio of winter 70 rye showed increasing tendency in the first 15days,from 22 to 36,while the other two breed had no significant change.