Study On Nitrogen Accumulation Characteristics Of Winter Wheat With Yield Of 10t/ha, Diagnosis And Nitrogen Application Technologies

Field experiments were carried out with different nitrogen application to study the responses of winter wheat in grain yield, nitrogen absorption and utilization, soil inorganic nitrogen accumulation, SPAD value in leaves and canopy vegetation index NDVI value using Hengguan 35 as material under the high-yield system at Qibin District, Hebi City, Henan Province from 2008 to 2010. At the same time, appropriate nitrogen fertilizer application of high-yield winter wheat producted and the feasibility of nitrogen nutrition nondestructive diagnosising using SPAD value or NDVI value were discussed. The main results were as followings.1. While basal fertilizer to reviving topdressing to jointing topdressing as 1:1:1, the nitrogen fertilizer amount was 180²40 kg/hm², grain yield of winter wheat was no significantly changed. It was 9 916.5¹0 032.0 kg/hm² at 2008/2009, and 8 254.2⁸ 637.9 kg/hm² at 2009/2010.Compared with the treatment using 240 kg/hm² nitrogen fertilizer, the treatment using 180 kg/hm² nitrogen fertilizer got higher ratio of input to output of nitrogen fertilizer (2.61 and 3.26), nitrogen harvest index (70.8% and 78.3%) and nitrogen efficiency. Its soil inorganic nitrogen accumulation amount in 0¹00 cm, nitrogen apparent loss amount and surplus amount were lower. It could be enough for winter wheat with high yield, high efficiency and environment freidenly producted at high-yield field.2. Using 80 kg/hm² nitrogen fertilizer at returning and jointing respectively, grain yield was 8 543.3 kg/hm². Compared with other nitrogen treatment at the same yield leavel (8 254.2⁸ 637.9 kg/hm²), its nitrogen harvest index (77.9%) and soil inorganic nitrogen accumulation amount in 0¹00 cm were no significantly changed.Its ratio of input to output of nitrogen fertilizer (4.64) and nitrogen efficiency were highest. Its nitrogen apparent loss amount (33.60 kg/hm²) and surplus amount (106.20 kg/hm²) were lowest. It could be the best nitrogen application.3. The nitrogen accumulation amount of upward plant of winter wheat with yield of 10t/hm² was increased with the development process and reached the maximum value in maturity stage. The total nitrogen accumulation was 289.51 kg/hm². The percentage of total nitrogen accumulation at returning, jointing, anthesis and filling was 22.1%, 39.5%, 80.4% and 85.2%. It was 22.1%, 17.4%, 40.9% and 19.6% from sowing to returning, returning to jointing, jointing to anthesis and anthesis to maturity. Nitrogen assimulation amount and nitrogen transportion amount after anthesis was 56.85 kg/hm²and 148.13 kg/hm². The contribution rate of grain nitrogen accumulation amount was 27.7% and 72.3%.4. The relationship between SPAD value and nitrogen content in leaves at returning (y = 0.1536x– 3.8568,R²=0.83) and jointing(y = 0.0273e^0.0955x,R²=0.81)were significantly relevance. The relationship between SPAD value and nitrogen content in plant was significantly relevance at returning(y = 0.2342e^0.0519x,R²=0.87), but it was not relevance at jointing. The relationship between SPAD value and nitrogen accumulation amount and yield at returning and jointing were not relevance. SPAD value at returning and jointing were unfavourable to nitrogen nutrition nondestructive diagnosising of winter wheat in high-yield field.5. The relationship between NDVI value and nitrogen content in plant nitrogen accumulation amount at returning (y =13.342e^2.7418x, R²=0.93) and jointing(y =3.25e3.9485x, R²=0.67)were significantly relevance. The relationship between the NDVI value and yield were fit by a polynomial. It was y =-5497.7x²+12315x+4391.1(R²=0.78)at returning, and y =15662x²-8409.7x+4162.2(R²=0.71)at jointing. NDVI value at returning and jointing were favourable to nitrogen nutrition nondestructive diagnosising of winter wheat in high-yield field.