Effects of flue-cured tobacco straw returning on late season rice production under tobacco-rice cropping patern
XIAO Han-qian1,TU Nai-mei1,2,GUAN Guang-sheng2,WANG Zhong-mei 2 (1.Tobacco Agricultural Experiment Station of Central-South China,Changsha 410128,China;2. College of Agronomy, HNAU,Changsha 410128,China)
On the basis of the experiments on different soil tillage and different amount of tobacco straw returning under tobacco-rice multiple cropping pattern,the effects of flue-cued tobacco straw returning on characters of late season rice, such as rice growth and development,yield formation,dynamic changes of soil active nutrients,disease severity of sheath blight (Rhizoctonia solani) were investigated. The results showed that compared with the control, tobacco straw returning could:1) Promote the potential of rice tillering and increase tiller number and the ratio of effective tiller. The treatment plowed with 100% straw returning was the best,with its maximum tiller number and effective tiller ratio increased by 6.5% and 7.9% respectively;2) Increase the dry matter accumulation. At maturing stage,the dry matter weight of the treatment with 100% straw returning under plowing and minimum tillage increased by 12.6% and 13.1% respectively;3) Increase rice LAI and delay the leaf senescence. The LAI of the treatments with 100% straw returning under plowing and minimum tillage increased 10.4% and 10.7% at booting stage;41.6% and 30.8% at maturing stage respectively;4) Could increase effective panicle number,spikelet number per panicle and seed setting rate synchronously,the yield was increasing with the amount of straw returning. The yield of the treatments with 100% straw returning under plowing and minimum tillage increased 14.1% and 11.4% respectively;5) Increase soil fertility and improve nutrition supply,showing higher content of active N,P,K at different stages. 6) Restrain the occurrence of sheath blight,with its severity much lower.