| With the adjustment of the agricultural cropping system in the middle reaches of the Yangtze River,the model of spring maize-late rice paddy and upland rotation is developing continuously,and the agronomic measures for high productivity are still to be explored.To this end,the maize-rice varieties and late rice seedling planting method experiment was carried out in 2015 at Tandian village,Jingmen City,Hubei Province.,Two selected spring maize varieties,four late rice varieties were used in this study.For each late rice varieties we setted large dish and small dish for seedlings.In 2016 we carried out the experiment of effect of return of corn stalks in maize-rice model.The treatments are as follws: straw crushing to cover the field(SC),the straw crushed into the field(SP),the straw is not returned to the field without tillage(NN),the straw does not return the field(NP).In the field of straw returning to the field,the straw degradation test was carried out to study the degradation of straw and nutrient release.Oure research indicates:1.Indica rice is more sensitive than japonica rice,and the small dish seedling caused a delay inthe Liang You 953 and Huang Huazhan by 12 days and 11 days than large dish seedling respectively is delayed by,and Huanghuazhan was not mature.The dry matter in the late maturing stage was significantly higher than that in the large dish(P <0.05).The yield of E Wan17,J036 and Liangyou 953 were significantly higher than those of the large dish,and the treatment of the small dish was 15.8%,11.7% and 18.2% respectively,which indicated that the small dish could also to meet the requirements of long seedling age.2.The annual yield of ZhengDan 958 that planting density of 90,000 / ha(Z6)and Liangyou 953 small dish(LX)was 18.73 t / ha,which was significantly higher than that of other combinations.The accumulated temperature production efficiency and annual effective accumulated temperature were also the highest.3.The results showed that the amount of straw released from the two kinds of straws was74.7% of the total amount of decay in the period of rapid decay and decay,74.8%.The rate of straw decay was about 50%,and there was no significant difference between the two treatments.Straw mulching straw nutrient release rate was: Potassium> Phosphorus>Nitrogen> Carbon.Straw pressing back to field straw nutrient release rate was:Potassium> Nitrogen> Phosphorus> Carbon.The release rate of potassium in straw was as high as 90%,and there was no significant difference between the two methods.The release rate of phosphorus was 76.8% and 69.8% respectively.The nitrogen content of straw was reduced by 76.3% and that of straw decreased by 65.3%,and the difference was significant.The carbon content of straw was reduced by 61.8%,and the carbon content of straw decreased by 57.3%,the difference was not significant.4.Soil active reducing substances showed a tendency to decrease with time,and the treatments were consistent.The content of active reducing substances in SP treated by SP was increased by 96.9%,60.0% and 82.9%,respectively,and the difference was significant.The content of SP reducible matter was significantly higher than that of NN,NP,SC and SCtreatments.The results showed that there was no significant difference in the content of active reducing substances in rice.5.SP was 23.9% and 28.3% higher than that of NN and NP treatments,respectively.The effective panicle number of straw mulching(SC)was higher than that of NN and NP treatments 18.9 % and 22.7% respectively.There was no significant difference in the number of effective panicles between SP and SC.The results showed that the return of maize straw had no effects on the growth of late rice,but it was beneficial to the tillering. |
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