Effects Of Interaction Between Density And Nitrogen On Grain Yield And Nitrogen Utilization Efficiency Of Winter Wheat

In order to verify the optimum nitrogen application rate and planting density for higher grain yield and nitrogen use efficiency, and to provide basis for the development of rational cultivation measures. This study was conducted from 2008 to 2009 and 2009 to 2010 at the experimental farm of shandong Agricultural University. Two cultivars,Tainong18(T18) and Shannong15(S15) representing large and middle ears respectively were used in this study. Under field condition, four regimes of planting density and three nitrogen rates were applied to study the interaction between nitrogen and density on grain yield and nitrogen use efficiency of wheat. This experiment mainly shows:1 Effects of interaction between density and nitrogen on grain yield and its components of wheatNitrogen and planting density on yield components were significantly affected. Spike of large ear cultivar of Tainong18 and middle ear cultivar of Shannong15 panicles per unit area and density as the nitrogen rate increased with the increase, grain number increased with increasing nitrogen, But with the increase of planting density showed decreased grain weight increased with nitrogen rate and planting density decreased.Nitrogen level and plant density significantly affected grain yield of wheat. Nitrogen under the same conditions, two cultivars of grain yield were shown to be increased with the increase of sowing and then decreased, but the highest grain yield of two cultivars of the seeding rate is inconsistent. Among them, the large ear cultivar of Tainong18 grain yield to sowing rate treatment for the 90 kg/ha the highest, and middle ear cultivar of Shannong15 to 75 kg/ha sowing treatment of the highest. Seeding rate under the same conditions, with the nitrogen rate increased grain yield in both cultivars showed a trend to increase, but the N180 to N 240 kg/ha, the production increased significantly lower rate. The highest grain yield in the seeding rate conditions, the two N treatment grain yield was not significant.Density of different nitrogen treatments on yield had significant interaction effects, calculation of nitrogen, the density effect of two factors known, nitrogen and density on yield of two cultivars of wheat have shown positive effects, and effects of the density effect is greater than N is the dominant factor affecting yield. The same density, nitrogen fertilizer effect of nitrogen rate increased with the increase, expressed as nitrogen 180kg/ha more than nitrogen 240kg/ha treatment, but the density effects and interaction with the nitrogen rate performance decreased with the increasing performance of 180 kg/ha Nitrogen more than Nitrogen 240 kg/ha processing; the same nitrogen content, the nitrogen effect, density effect, and interaction changes of the same cultivars large ear cultivar of Tainong18 as the density increases the effect of increased first and then decreased, showing the highest density 90 kg/ha processing, density 105 kg/ha treatment, followed by the lowest density of 75 kg/ha treatment, and middle ear cultivar of Shannong15 as the density increases the effect of decreasing trend has been presented, showing the highest density 75 kg/ha processing, density 90 kg/ha treatment, followed by the lowest density of 105 kg/ha treatment.2 Effects of interaction between density and nitrogen on Photosynthesis of wheatIncreased planting density and nitrogen will increase the two cultivars of Tainong18(T18) and Shannong15(S15) representing large and middle ears of after of flowers the maximum photosynthetic rate, but the latter will increase planting density, canopy apparent photosynthesis rate at the same time decay speed up, and nitrogen fertilization of wheat canopy apparent photosynthesis rate will slow down the decay. Large ear cultivar of Tainong18 in the various stages of flowers after the value of canopy apparent photosynthesis and yield were significantly or very significantly correlated, in the grouting stage middle ear cultivar of Shannong15 only the value of canopy apparent photosynthesis and yield related to significant levels.Flag leaf of two wheat cultivars were expressed as the maximum photosynthetic rate with the increase of sowing density decreased with the increase of nitrogen increases. As the sowing density and nitrogen fertilizer increased, the two wheat cultivars at flowering stage of maximum leaf area index showed a gradually increasing trend. Reduce planting density and nitrogen fertilization after flowering will be delayed flag leaf photosynthetic rate and leaf area index of the attenuation.Density mainly affects the leaf area index and thus lead to changes in canopy apparent photosynthesis rate, and nitrogen level affected mainly the change of flag leaf photosynthetic rate and thus lead to changes in canopy apparent photosynthesis rate, photosynthetic rate of population density of the dominant factors, Density and Nitrogen control the change of canopy apparent photosynthesis of production.3 Effects of interaction between density and nitrogen on nitrogen utilization efficiency of wheatNitrogen under the same conditions, planting density per unit area increased significantly the accumulation of nitrogen, with the planting density, nitrogen agronomic efficiency, nitrogen uptake efficiency, productivity and nitrogen partial nitrogen use efficiency at first increases and then decreases trend, in which large ear cultivar of Tainong18 90 kg/ha, middle ear cultivar of Shannong15 to 75 kg/ha conditions, these indicators have reached the maximum. Under the same conditions, planting density, nitrogen fertilization significantly increased N accumulation per unit area in the amount of plants, but significantly reduced agronomic N use efficiency, nitrogen uptake and nitrogen utilization of partial productivity indicators, but between the two levels of nitrogen fertilizer application support Use efficiency was no significant difference. T18 in the D90, N180 treatment, S15 in the D75, N180 treatment, to achieve yield and nitrogen use efficiency for improved synchronization.The grain yield and dry matter accumulation and nitrogen use efficiency related to the correlation analysis between indicators, N agronomic efficiency, N recovery efficiency , N utilization efficiency and N accumulation amount significantly between or highly significant positive correlation, indicating Involved in this trial efficiency index of nitrogen fertilizer level and planting density by the impact of the changes showed the same trend. Also shows that N utilization efficiency and N accumulation amount was significantly negatively related to N agronomic efficiency, N recovery efficiency and grain yield showed significant or highly significant positive correlation, grain yield, N accumulation amount and dry matter accumulation was significantly correlated with economic factors and the grain yield was significantly negatively correlated. Suggesting that the impact of nitrogen level and plant density, nitrogen uptake per unit area to reduce nitrogen use efficiency is the main reason for increased grain yield caused by N agronomic efficiency and N recovery efficiency of synergies increase, while grain yield increased mainly attributed to due to the increase in dry matter accumulation.