The Study Of Nitrogenous Fertilizer And Planting Modes On The Relationship Between Individual And Colony Of Winter Wheat In The Sub-humid Area Ecology System

The field experiment was conducted at the first Agronomy Research Farm, Northwest Sci-tech University of Agriculture and Forest in Yang ling, which were in the south part of Loess Plateau with about 628.8mm precipitation each year. Xiaoyan 22 was used as indicating crops to study the relationship between individual and colony of winter wheat and yield in different planting modes(control-C, plastic sheet-mulching-PSM, ridge-furrow tillage-RFT and plastic sheet-mulching on ridge-PSMR) and different nitrogen fertilizer application(no nitrogen application and nitrogen application 120kg/hm2). The main results showed as follows: 1. The effects of nitrogen fertilizer and planting modes on the flag leaf, especially in the growth anaphase, were the basis of assimilation ability of source. Results showed that nitrogen fertilizer were able to increase the nitrogen content of flag leaf significantly, especially at jointing stage. But during filling stage and maturing stage, it increased slowly. The effects of planting modes were less than nitrogen fertilizer. The flag leaf nitrogen content of PSMR and PSM were higher than the other two planting modes, during the filling stage and maturing stage, especially the effects of PSM were obvious in the filling stage. They individually increased 12% and 29% comparing to C. The effects of nitrogen fertilizer and planting modes on chlorophyll were almost the same as on the flag leaf nitrogen content. The area of green leaf under the condition of nitrogen fertilizer were increased to 23.4%,20.7%,15.3% and 8.9% comparing to non-nitrogen fertilizer. At seeding stage, reviving stage , jointing stage and anthesis stage, the effects of nitrogen fertilizer on the area of green leaf are the largest at seeding stage. PSM and PSMR's green leaf area were higher than C significantly. PSMR's green leaf areas were the largest. Nitrogen fertilizer can significantly increased flag leaf's photosynthetic rate. At jointing stage, filling stage and maturing stage, they increased to 7.8%, 15.9% and 7.2% than non-nitrogen application. The changes of Pn were significantly different at 0.01 in different planting modes. PSMR's Pn were the largest, 16.291μmolCO2m-2.s-1. Correlation analysis showed that increased flag leaf's nitrogen content were beneficial to grain yield, especially in the growth anaphase. Increasing flag leaf's nitrogen content were beneficial to increasing chlorophyll and Pn. So flag leaf's nitrogen content are the basis of assimilation ability. Study showed that not only nitrogen fertilizer can increased flag leaf's nitrogen content significantly, but also PSM, PSMR and RFT can increased it significantly, especially PSM AND PSMR. 2. Nitrogen fertilizer and planting modes mainly affected canopy tiller, leaf area and biomass over-ground, so as to affect colony structure. In every planting modes, nitrogen fertilizer can increase colony tiller significantly. The colony tiller were different in different planting modes. C, PSM, RFT and PSMR's colony tiller individually were 378/m2,405/m2,452/m2 and 512/m2. PSMR,RFT and PSM increased 26%,16% and 7% comparing to C. We can see that PSMR was the most beneficial to increase colony tiller per area. Correlation analysis showed that colony tiller and grain yield were positive correlation. So we can increase colony tiller to some extent to increase grain yield. Biomass over-ground were the same as whether using nitrogen or not. They were all increased in the initial filling stage, and then decreased in filling stage and harvest time. Biomass over –ground were different in different planting modes. They were higher comparing to the non-mulching. The biomass over-ground sequence from large to small was PSMR, RFT, PSM and C. The effects of nitrogen fertilizer on dry matter accumulation were different. PSMR's dry matter accumulation were higher than PSM at harvest time, so it was beneficial to increase grain yield. From the colony tiller and biomass considering, PSMR and PSM were the best planting modes. To the RFT, colony tiller on ridge had close relation with sheet-mulching. PSMR could increase the colony tiller significantly. LAI was increased at the first and then decreased. The largest LAI was 1.919 in anthesis and the least was 1.292 in mature. The changes of LAI were significantly different at 0.01 in different nitrogen treatment. Nitrogen fertilizer could increased 20% to LAI. PSMR and RFT's LAI were higher than the other two planting modes, but DIFN was reverse. The DIFN became small from mature to anthesis. RFT and PSMR's DIFN were significantly different at 0.01 from the other two planting modes. C's DIFN was the largest without nitrogen, PSM's DIFN was the least with nitrogen. 3. Nitrogen fertilizer and planting modes affected the root characteristic significantly, but the relation between the ratio of root to shoot and root biomass with grain yield were not different significant. The root weight were gradually increased from reviving stage to booting stage. It reached maximum at booting stage. Besides PSM, nitrogen fertilizer didn't affect the root weight significantly. PSM, RFT and PSMR's root biomass were larger than C's in reviving stage. But after jointing stage, PSM and PSMR's root biomass were almost the same as C's, even less than C's. that perhaps were affected by the dying of the root. The root quantity per plant were significant different in different planting modes in reviving stage. C and PSM's root quantity were more. PSM and PSMR's root quantity per plant were decreased significantly when entering into booting stage. Nitrogen fertilizer made the ratio of root to shoot decreased. The changes of the ratio of root to shoot were significantly different at 0.01 in different planting modes. The ratio of root to shoot's sequence from large to small was RFT, PSMR, C and PSM. Correlation analysis showed that the ratio of root to shoot were negative relation to grain yield, but not significantly. Dry weight of root have nothing with grain yield. 4. Nitrogen fertilizer and planting modes could affect grain yield through spike quantity and 1000 kernel dry weight. Study showed that grain yield's sequence from large to small was PSMR, RFT, PSM and C. They individually increased to 27%,20% and 9% comparing to C. The different level reached to 0.01.PSMR's spike quantity were largest. Nitrogen fertilizer can significantly affect spike quantity and 1000 kernel dry weight, but not affected kernel quantity per spike significantly. However, planting modes can affect sink volume per spike significantly. Nitrogen also can affect the HI(harvest index) significantly. It can increase 10% to HI. Study showed that PSMR's grainyield were largest, 8899kg/hm2. The NUE(nitrogen use efficiency)'s sequence from large to small is PSMR, RFT PSM and C. PSMR's NUE increased 37% comparing to C's NUE.