Wheat Growth Dynamic,Yield And Nutrient Use Efficiency Associated With N And P In Different Planting Patterns

Wheat/maize relay-intercropping system, which had an advantage of yield compared with monoculture wheat, is the dominating rainfed pattern in Sichuan province. In order to explore the production-advantage mechanism, nutrient use efficiency and rational nitrogen management strategies for improving the productivity of intercropped wheat, it is meaningful to do this research about the interaction between wheat and maize on plant growth and nutrient utilization. A field experiment was conducted in 2013 with four nitrogen and three phosphorus application rates (0,60,120,180 kg N/hm~2, marked as N1, N2, N3, N4; 0,90,180 kg P/hm~2, marked as P1, P2, P3, respectively) under three planting patterns including wheat monoculture (W), wheat/maize strip relay-intercropping (W/M) and wheat/empty crop strip [W/(M)]" to investigate the effect of different nitrogen and phosphorus on growth and development, nutrient uptake and use efficiency, grain yield, and soil fertility with monoculture/intercropped wheat. The main results are as follows:(1) Nitrogen and phosphorus fertilizer could promote the growth and development of wheat. Aboveground biomass and nutrient uptake of wheat increased firstly and then decreased as nitrogen increased, before jointing stage, wheat grows slowly, after jointing stage, aboveground biomass and nutrient uptake increased significantly and then decreased as nitrogen increased, N3 was the largest treatment, aboveground biomass and nutrient uptake of wheat were the same rule as nitrogen with different phosphorus fertilizer, P2 was the largest treatment.(2) Nitrogen fertilizer could promote the N, P, K content and uptake of wheat, in early growth stage, the N, P, K content was highest in N2 treatment, and in the later growth stage, N, P, K content and uptake of each organ arrived the highest point in 120 kg/hm~2, more than 120 kg/hm~2, the N, P, K content and uptake of each organ had no significant increase with the increase of nitrogen. Phosphorus fertilizer also could promote the N, P. K content and uptake of each organ, the N content of each organ was largest in P2 treatment, the N uptake of each organ was largest in P3 treatment, but there was no significant difference with P2 treatment.(3) Compared with the monoculture wheat, intercropped wheat had advantages of yield, a higher nitrogen and phosphorus absorption ability and a better use of nitrogen and phosphorus fertilizer. When different nitrogen fertilizer, aboveground shoot biomass and yield of the intercropped border row wheat average increased by 23.81% and 27.27% than monoculture wheat, yield, biomass and harvest index of the intercropped wheat average increased by 17.81%,15.74% and 4.18% than monoculture; but also nitrogen accumulation, grain nitrogen accumulation, nitrogen partial factor productivity of wheat in W/M pattern were significantly higher than monoculture wheat under the different nitrogen application rates, average increased by 48.91%,32.63% and 19.08%, respectively. When different phosphorus fertilizer, aboveground shoot biomass and yield of the intercropped border row wheat average increased by 23.83% and 13.20% than monoculture wheat, yield, biomass and harvest index of the intercropped wheat average increased by 6.32%.4.67% and 1.12% than monoculture.(4) In wheat/maize intercropped system, the kind of interaction relationship between wheat and maize was affected by different nitrogen and phosphorus. When different nitrogen fertilizer, compared with (W/M), grain yield of wheat in W/M pattern reduced by 8.33%,3.13% and 4.51% under the N1, N2 and N4, respectively, and grain yield increased by 14.13% under the N3. When different phosphorus fertilizer, compared with (W/M). grain yield of wheat in W/M pattern reduced by 2.52% and 1.11% under the P1 and P3 respectively, and grain yield increased by 2.53% under the P2. It explained that intercropped wheat may be inhibited by intercropping maize with low nitrogen and phosphorus application rate. In contrast, wheat development in intercropping could be promoted by sufficient nitrogen and phosphorus application, so interaction between maize and wheat may enhanced these process, but sufficient nitrogen and phosphorus fertilizer for maize and wheat is essential to promote the growth of relay-intercropping wheat.The study showed that:nitrogen and phosphorus application fertilizer can obviously promote the growth of wheat, the biomass, yield and nutrient uptaking with the nitrogen and phosphorus application fertilizer increasing, but the growth of wheat is not conducive with too much application fertilizer, the suitable nitrogen and phosphorus is 120 kg/hm~2 and 90 kg/hm~2;intercropped wheat with a yield advantage compared with monoculture wheat, and mainly comes from the border row of intercropped wheat; in wheat/maize intercropped system, there is a competition for nitrogen and phosphorus, so sufficient nitrogen and phosphorus fertilizer for maize and wheat is essential to promote the growth of relay-intercropping wheat.