Effects Of Tillage Practices And Planting Patterns On Rice Population Growth Dynamic And Yield In Rice-Wheat System

This study was carried out at the Junchuan and Huaqiao town in Hubei Province of China from2011to2012. The field experiment was take rice-wheat rotation system as the object, five cultivation patterns treatments were established with conventional-till and transplantation (CTTP), conventional-till and cast-transplanted (CTCT), No-tillage and cast-transplanted (NTCT), conventional-till and direct seeding (CTDS), no-tillage and direct seeding (NTDS), conducted to study the effects of different cultivation patterns to the rice grain yield, and evaluated the economic benefit. The main results are summarized follows:1. The yield of CTDS and NTDS are9.6t·hm-2and9.0t·hm-2, decreased significantly of the yield compared with cast-transplanted rice, the main cause is the panicle number, seed setting rate and1000-grain weight is lower of CTDS and NTDS treatment. Compared with cast-transplanted rice, the CTDS and NTDS decreased the LAI of Mid-tillering stage(Mt), has a tendency to lower the LAI of every stage, and then increased the light transmittance both from top and bottom; The high rate of leaf area is71%and72%respectively, highly significantly than others treatments; the dry matter of vegetative growth stage is highly than reproductive growth period for direct seeding, the contribution rate of dry matter of grain before flowing is highly than after flowering.The nitrogen content of the plant is223kg·hm-2and226kg·hm-2in the maturity stage (M) of CTDS and NTDS, significantly lower than others treatments, and has a tendency to lower the leaf net photosynthetic rate of the heading stage (H), so the NSC is decreased significantly of H and M stage. The CTDS and NTDS increased the N recovery efficiency (NRE) significantly, but decreased the partial factor productivity of applied, N agronomic efficiency (NAE), N physiological efficiency (NPE) significantly.2. The yield of CTCT and NTCT is highly significantly than other treatments, increased5%,4%of the yield respectively in2012, and increased15%,11%of the yield respectively in2011compared with cast-transplanted, the main cause is the panicle number and1000-grain weight is higher than other treatment. Compared with transplantation, the cast-transplanted rice tillering speed is fastly and the amount of peak seeding is highly. The difference of LAI is not clear between different stage, but CTCT and NTCT has a tendency to increased the LAI; The CTCT and NTCT increased dry matter accumulation of Mt to panicle primordium differentiation stage.The nitrogen content of the plant is223kg·hm-2and230kg·hm-2in the H stage of CTCT and NTCT, highly significantly than other treatments; Compared with transplantation, the difference of nitrogen content is not clear between M stage, but has a tendency to increased the nitrogen content; The leaf net photosynthetic rate is20.55umol/(m2-s) and20.69umol/(m2·s) respectively, higher than other three treatments, so increased the NSC of M stage significantly. Meanwhile, cast-transplanted rice increased the NAE, NPE and the partial factor productivity of applied, decreased the NRE significantly.3. The effects of CT and NT treatment to rice population structure characteristics and yield is no significant. Compared with CTDS, NTDS decreased the NAE, NPE and the SPAD of H stage significantly, but increased the SPAD of Mt stage and the NSC in the grain of M stage significantly. Under the same cultivation pattern, NT decreased11%of the cost.4. Compared with transplantation, the CTDS and NTDS decreased28%and37%of the cost respectively, the main cause is the CTDS and NTDS decreased two-thirds of quantity of labor force, so the composite economic results are increased21%and24%respectively. The cost of CTCT and NTCT is11043and9843yuan per hectare, decreased21%and30%respectively compared with transplantation. The labor cost of CTCT and NTCT is4800yuan per hectare, decreased38%compared with transplantation, so the composite economic results are increased38%and47%respectively. In general, the rice population structure characteristics and yield of cast-transplanted is superior to transplantation and direct seeding. Therefore we could extend the NTCT to improving economic efficiency, but if we wanted to increasing the efficiency of labor productivity and cost savings, the NTDS mode is best.