Research On The Effect Of Duck-raising In Paddy Fields On The Crop Growth And The Yield

The combination of the rice direct sowing in simplified cultivation and the integrated rice-duck farming technology was of great importance to achieving the target of high quality,high yield,high efficiency and safety in the production.In this regard,this paper drew lessons from the previous researches on rice direct sowing and rice-duck farming,and proposed the idea of “cropping and farming” technology,which meaned raising the ducks under rice direct sowing.A field comparison experiment was carried out,which involved the regular rice direct sowing,regular duck raising under rice direct sowing,duck raising under semi-solid rice direct sowing and duck raising under precision hill-direct-sowing.The growth properties of the plant root system,the shoot dry matters accumulated,tiller and the SPAD value were studied to see whether duck raising under rice direct sowing could improve the plant structure and influence the yield and yield components.The results were as follows:(1)Yield differences existed among different duck raising methods under rice direct sowing.Comparing with the regular rice direct sowing(CK),duck raising under precision hill-direct-sowing(RDP),duck raising under semi-solid rice direct sowing(RDS)and regular duck raising under rice direct sowing(RD)all saw an increase in the yield.The RDP treatment saw the biggest increase,that is,an average 6.00%(5.15% to 6.89%),the RDS,2.45%(2.00% to 2.91%)and RD,the smallest increased,all from the CK level.A further analysis of the yield components showed that,compared with CK,the RDP treatment significantly increased the number of the productive panicles,grain number per panicle and the maturing rate by an average 8.11%(7.27% to 8.96%),11.15%(9.94% to 12.36%)and 5.48%(1.96% to 9.01%)respectively.RDS and RD treatment also saw an increase in the three items,which were 1.43%(0.45% to 2.40%),7.69%(4.50% to 10.89%)and 5.18%(1.72% to 8.64%)respectively,while 1000-grain weight in the RDP,RDS and RD treatments all declined.(2)Results from the experiments in double cropping showed that compared with CK,the RDP,RDS and RD treatments had tiller advantages.The tiller increased fast at the early middle stage of the rice growth period and stayed stable at the late stage and the peak value of the tiller in the middle and late growth period was reduced,inhibiting the birth of invalid panicles.While the RDS and RD treatment saw little differences in the shoot dry matters accumulated compared with the CK treatment,the RDP treatment,which had basically the same shoot dry matters accumulated as the CK treatment did at the five-leaf stage,saw a significant increase of the shoot dry matters accumulated from the tiller stage to the fullheading stage,with the average increased rate being 8.41% to 31.00%.In addition,the RDP treatment saw a larger SPAD value than the RDS,RD and the CK treatments from the fiveleaf stage to the maturity stage while the SPAD value of the RDS,RD and the CK treatments had little difference.The SPAD value of the RDP treatment from the tiller stage to the maturity stage was larger than that of the CK treatment at each stage,the biggest difference being at the heading stage of both the early rice and the late rice,that was,0.59 and 2.79 respectively.(3)There were differences in such root properties as the root number per plant,root length and the root volume among different treatments.The RDP treatment had larger root number per plant,root length and the root volume than the RDS,RD and the CK treatments,while these properties in the late three treatments were basically the same.Compared with the CK treatment,RDP saw stronger activity of the roots from the five-leaf stage to the full heading stage,increasing by a largest 7.49% at the heading stage of the early rice,although the average increase didn’t reach a significant difference.The activity of the roots in the RDS,RD and the CK treatments was insignificantly different.In addition,compared with the CK treatment,the RDP treatment saw larger total absorbing area and active absorbing area of the roots,the average increase rate being 0.56% to 6.77%.The difference in the two items was not significant among the RDS,RD and the CK treatments.These results indicated that the duck raising under precision hill-direct-sowing had better activity of the roots,roots absorbing area,shoot dry matters accumulated and the root volume than the regular rice direct sowing.The activity of the roots stayed at a high level in the whole growth period and the aging of the rice at the middle and late stages slowed down,facilitating the growth of the shoot and the formation of the yield.(4)Compared with the RDS and the RD treatments,the RDP treatment didn’t see a significant difference in the structure components.However,compared to the CK treatment,RDP saw smaller basal stem width of the plants from the late tiller stage to the full-heading stage and a larger canopy width,ensuring certain looseness in the plant structure.The opening angel,drooping angel and leaf length of the flag leaves and second leaves increased and the opening angel,drooping angel of the third leaves and fourth leaves decreased,making plants thick up and sturdy below.The leaf area of the flag leaf,second leaf and third leaf increased,enabling the upper part of the plant to contain more leaf area.The plant roots grew harder.The basal leaf height increased and SPAD value of different phyllotaxises went up,which slowed down the aging of the leaves.Therefore duck raising under precision hilldirect-sowing could optimize the plant structure,improve the photosynthetic efficiency,and increase organics accumulation,thus ensuring a high rice yield.