| Green manure resources are rich in our country,generally can be divided into two categories,leguminous green manure and non leguminous green manure,leguminous green manure and returning the leguminous green manure is China southern paddy cultivation measures.Due to the limitation of its own C/N,legume and non-legume green fertilizers have some limitations when returning to the field alone.In recent years,the mixed return of green manure has become a new technology applied to crop cultivation.Therefore,the double cropping rice production and soil nutrient changes under the mixed return of leguminous and non-leguminous green manure mode are worth studying.In this paper,the effects of legume and non-legume green manure returning to the field on double cropping rice yield and soil nutrients were studied by field plot experiment and indoor decomposition experiment.The characteristics of legume and non-legume green manure returning to the field and nutrient release of N,P and K were discussed,so as to screen out a green manure returning to the field suitable for the production of rice fields in southern China.The main findings are as follows:1.Mixed legume and non-legume green fertilizers can effectively increase leaf chlorophyll content in late growth period of double cropping rice and delay the decrease of net photosynthetic rate of sword leaf.Compared with the combination of legume and non-legume green fertilizers,leaf SPSD of early and late rice increased by 0.88%～1.96%and0.47%～1.55%at full heading stage,respectively,and net photosynthetic rate of sword leaf increased by 4.70%～11.40%and 1.00%～7.52%at maturity stage,respectively,under the combination of legume and non-legume green fertilizers.Among them,the mixed returning of milk vetch and rape plants was the best,with an increase rate of 1.96%,1.55%and 11.40%,7.52%,respectively.2.Mixed legume and non-legume green manure is beneficial to dry matter production and distribution of double cropping rice.The dry matter accumulation of early rice at mature stage was increased by 10.16%-18.12%and 4.23%-11.75%,respectively.The proportion of root and stem decreased by 0.56%-0.87%,0.24%-0.55%,1.32%-1.99%and 0.41%-1.08%,and the proportion of ear increased by 1.29%-3.05%and 1.20%-2.96%,respectively,compared with that without green fertilizer and Chinese milk grass returned to the field alone.Late rice mature period of dry matter accumulation were increased by 5.68%～11.40%,2.39%～7.93%,roots,leaves fell 0.29%～0.44%,0.08%～0.23%and 1.09%～2.39%and 0.01%～1.31%,increased by 0.35%～0.79%,0.16%～0.60%.Among them,the mixed returning of milk vetch and rape plants showed the best performance in increasing dry matter accumulation and panicle proportion in early and late rice mature stage.3.Combination of legume and non-legume green manure could increase the contents of N,P and K and the accumulation of N,P and K in different parts of early and late double cropping rice,and the effect was better than that of green manure alone.Compared with no green manure returning,the panicle nitrogen and phosphorus contents of early and late rice were increased by 21.90%,18.56%,19.09%and 26.65%,respectively,and the accumulation of nitrogen and phosphorus was increased by 48.42%,44.20%and 31.17%,42.57%,respectively,by the mixed returning of milk vetch and rape plants.The potassium content of panicle increased by 23.08%and 23.72%,and the potassium accumulation increased by 29.91%and 28.04%,respectively,at the mature stage of early and late rice.4.The mixed return of leguminous and non-leguminous green fertilizers could significantly increase the effective panicle number,seed setting rate and yield of double cropping rice,and there was a significant positive correlation between the effective panicle number,seed setting rate and yield of double cropping rice(P<0.05).The yield of double cropping rice was the highest with a two-year average yield of 17.44t/hm~2,which was significantly increased by 14.74%and 9.32%compared with that of green manure not returned to the field and milk vetch returned to the field alone,respectively.The yield of double cropping rice was the second,and the average yield of two years was 17.11t/hm~2,which was12.56%and 7.27%higher than that of green manure not returned to the field and Chinese vetch returned to the field alone,respectively.5.The decay of green manure can be divided into three stages:rapid decay stage(0-20d),medium decay stage(20-70d)and slow decay stage(70-110d).On the 110th day of decomposition,the cumulative decay rate of green manure was 57.61%～66.25%,and the cumulative decay rate was the highest in the mixed returning of Chinese sinica and rape.The cumulative release rates of N,P and K were 57.75%-69.69%,55.54%-64.38%and 93.7%-95.71%,respectively,which showed that K>N>P,the highest N and P release rates were found in the mixed return of milk vetch and rape plants,and the highest K release rates were found in the mixed return of pea and ryegrass.6.Under plot experiment,the contents of soil organic matter,total nitrogen,total phosphorus,total potassium,alkaline hydrolysis nitrogen,available phosphorus and rapidly available potassium increased by 1.61%～13.15%,2.79%～17.14%,4.17%～18.74%,1.69%～6.73%,1.16%～2.59%,1.17%～4.29%,0.24%～2.91%,respectively.Under indoor decomposition test,soil organic matter,total nitrogen,total phosphorus,group potassium,alkali-hydrolyzed nitrogen,available phosphorus and rapidly available potassium were increased by 66.81%～88.54%,17.76%～26.28%,8.63%～15.78%,8.76%～12.80%,15.82%～23.49%,12.97%～22.05%,25.10%～31.64%,respectively.Under the field plot test and indoor decomposition test,the mixed return of green manure was beneficial to increase the contents of soil organic matter,total nitrogen,total phosphorus,total potassium,alkali-hydrolyzed nitrogen,available phosphorus and rapidly available potassium,and the effect of soil fertilizer cultivation was better than that of green manure alone.Among them,the mixed returning of milk vetch and rape plants had the best improving effect on the contents of soil organic matter,total nitrogen,total phosphorus,alkaline hydrolysis nitrogen nitrogen and available phosphorus,and the mixed returning of pea and ryegrass had the best improving effect on the contents of soil total potassium and available potassium. |
PDF Full Text Request