Effect Of Nitrogen Application And Seeding Density On Canopy Temperature Diurnal Change And Biological Properties Of Two Wheat Varieties With Different Spike Types

A field experiment was carried out to study the effect of nitrogen and seeding density on Canopy temperature diurnal change, SPAD, Cell membrane permeability, Flag leaf green area, Photosynthetic rate, grain filling rate, yield and yield component elements of two wheat varieties with different spike types in the grain-filling stage. In order to discuss the relationship between biological characters and canopy temperature,useing the canopy temperature to evaluate wheat nitrogen nutrient status, predict wheat yield, and guide agricultural production.The major findings are as follows:(1) It showed that,the canopy temperature can be changed after fertilization(120-360㎏ N/hm~2),the Nutrient stressed plant had lower canopy temperature (8:00-10:00) compared to fertilized plant in the morning , but the trend of canopy temperature in the afternoon(14:00-18:00) and morning were opposite. There were no significant canopy temperature differences among planting densities in this field experiment.(2) The flag leaf green area, SPAD, Cell membrane permeability and Photosynthetic rate of two wheat varieties with different spike types can be changed after fertilization in the grain-filling stage, the grain filling rate of N240 and N360 of two spike wheat is greater than N0 or N120 treatments' in the grain-filling late stage.(3) In different densities, the theoretical yield and spike number per hectare of two spike types wheat increased along with nitrogen increasing. With nitrogen increasing, the grain number per spike and 1000-grain weight of heavy-ear winter wheat increased too, while the grain number per spike of multi-spike wheat increased and 1000-grain weight of multi-spike wheat decreased with nitrogen increasing.(4) The flag leaf green area, SPAD, Cell membrane permeability and Photosynthetic rate, the theoretical yield, 1000-grain weight, grain number per spike and spike number had positive or negative correlation with the canopy temperature of 8:00, 10:00, 14:00, 16:00 and 18:00 during grain-filling stage. The correlation of 16:00 was the largest one, so it was suggested that canopy temperature of 16:00 can be used as an indicator to estimate yield or guide N fertilizer application.