Effects Of No-tillage In Paddy Fields On Root Properties And Yield Of Super Rice

The root properties, the dry matter accumulation and the yield of superhybrid rice were studied under the different tillage system. The field experiment with super hybrid rice Liangyoupeijiu was conducted in Changsha in 2006 and 2007. The treatments of conventional tillage and transplanting (CT), conventional tillage and broadcasting (CB), no-tillage and transplanting (NT), and no-tillage and broadcasting (NB) were arranged by using freedom plot design and with replications. The results were summarized as follow:1. In DB treatment, the root\shoot ratio and root dry weight of NT rice at maximum tillering stage were 23.42% and 3.33% higher than those in CT treatment; and the root\shoot ratio and root dry weight of NT rice at booting stage were 30.01% and 18.75% higher than those in CT condition; the volume of the NT root were 21.29%,4.32% and 18.87% higher than those in CT condition at maximum tillering stage, booting stage and full heading stage. In RT condition, the root\shoot ratio and root dry weight of NT rice were 10.24% and 10.57% higher than those at maximum tillering stage in CT condition, 22.67% and 4.35% higher than those at panicle initiation stage .2. The results showed that oxidation ability of rice roots in NT at every growth stage was higher than those in CT, oxidation ability of rice roots were raised by no-tillage and direct broadcast. 64.66% of roots were centered in 0-5cm soil layer of DB rice, root weight of NT rice in 15-20cm and 20-25cm soil layer was higher than those of CT rice. The dry matter accumulation and its distribution of NT rice at mature stage were higher than those of CT rice.3. Under the direct broadcasting condition, the total N absorbing capacity was similar, the total P and K absorbing capacity of NT rice was 11.52% and 10.44% higher than those of CT rice; in the raised seedlings and transplanted condition, the total N and P absorbing capacity of NT rice was 13.52 and和0.67% higher than those of CT rice, the total K absorbing capacity was 12.36% lower than those of CT rice. The plant height of the DB rice in CT condition was the highest in the four treatments, and the DB rice in NT condition was the lowest.4. The harvest index and spikelet number per panicle of NT rice were higher than those of CT rice. The yield of DB rice in NT condition was highest, 10798.3 kg·hm^-2, was not significant between RT rice in CT condition. The rice yield superiority in NT was obvious compared with CT, which was the reaction of good root properties in NT.