Effects Of Nitrogen Application On Carbon And Nitrogen Alteration In Soil Rhizosphere , Nitrogen Uptake And Utilization Of Plant In High Yielding Wheat

Two years field experiments were conducted at Wenxian and Lankao sites of Henan Province using two wheat varieties of Yumai 49-198(multi-spike phenotype) and Lankao Aizao 8(large-spike phenotype) and five nitrogen rates(0,90,180,270,360 kg/hm~2), the main results showed as follow;1. Soil inorganic nitrogen existed significant difference among the five nitrogen rates and various growing stage.Soil inorganic nitrogen of different nitrogen application rate had on significant differences when added more N beyond 180 kg/hm~2 or 270 kg/hm~2 . When nitrogen application rate haven't been exceeded 180 kg/hm~2,nitrogen application rate haven't increased apparent nitrogen loss by a large margin.When nitrogen application rate have exceeded 270 kg/hm~2, nitrogen application rate have increased apparent nitrogen loss dramatically.Under this trial condition,apparent nitrogen loss of nitrogen application amount ranged from 180 to 270 kg/hm~2 is lower.2. Nitrogen apparent increased the contents of total of total N,acid hydrolysable N and nonhydroolysable N.In the period of shooting, the contents of total of total N,acid hydrolysable N and nonhydroolysable achieved highest at the lever of nitrogen application rate ranged from 270 to 360 kg/hm~2 in Wenxian respectively,and nitrogen application rate in Lankao is ranged from 180-27 kg/hm~2.In the period of harvesting, the contents of total of total N,acid hydrolysable N and nonhydroolysable achieved highest at the lever of nitrogen application rate ranged from 180 to 270 kg/hm~2 in the sites of Wenxian and Lankao.The effect of N application on different fractions of acid hydrolysable N is different between two sites and two types. Nitrogen apparent increased the contents of different fractions of acid hydrolysable N of Lankao aizao8 in Wenxian,and the contents of Ammonium N ,Amino acid N and Amino sugar N declined with the increase of nitrogen fertilization rate when added more N beyond 180 kg/hm~2. Nitrogen apparent increased the contents of Amino acid N and Amino sugar N of Yumai 49-198 in Lankao,the content declined with the increase of ntrogen fertilization rate when added more N beyond 180 kg/hm~2.3. Nitrogen apparent rate had little influence on soil C/N ratio of different fractions of acid hydrolysable N.Compared with the period of shooting,soil C/N ratio of Ammonium N of Yumai 49-198 in Wenxian increased a little between different nitrogen apparent rates,and soil C/N ratio of Amino acid N,Amino suger N,HUN declined between different nitrogen rates except the treatment of 90 kg/hm~2 nitrogen apparent rate in the period of harvesting .Compared with the period of shooting, soil C/N ratio of Amino acid N,Amino suger N,HUN,Ammonium N declined between different nitrogen rates except the treatment of 90 kg/hm~2 nitrogen apparent rate of Lankao aizao8 in Wenxian; Compared the period of harvesting with the period of shooting, soil C/N ratio of Amino acid N,Amino suger N,HUN,Ammonium N increased when nitrogen apparent rate exceeded 180 kg/hm~2,and soil C/N ratio of different fractions of acid hydrolysable were on a declining curve when nitrogen apparent rate didn't exceed 180 kg/hm~2. Compared the period of harvesting with the period of shooting, soil C/N ratio of different fractions of acid hydrolysable were on a declining curve between different nitrogen application rate.4. Seed and plant nitrogen uptake of Yumai 49-198 had on significant difference when nitrogen apparent rate exceeded 90 kg/hm~2;seed and plant nitrogen uptake of Lankao aizao8 had on significant difference between different nitrogen apparent rates of 180 and 270 kg/hm~2 in Wenxian. Seed and plant nitrogen uptake had on significant difference when nitrogen apparent rate exceeded 180 kg/hm~2 in Lankao.5. Wheat yeild of 2007-2009 years indicated that Yumai 49-198 had the highest yeild at 270 kg/hm~2 at Wenxian and Lankao sites while Lankao aizao 8 had the highestyeild at 180 kg/hm~2.The results which fitted with a quadratic equation between wheat yeild and nitrogen apparent rates indicated that the nitrogen apparent rates of Yumai 49-198 which made wheat yeild achieved the highest yeild were 233 kg/hm~2 and 249 kg/hm~2 respectively at Wenxian and Lankao sites, while economically optimal N rates were 147 kg/hm~2 and 167 kg/hm~2 respectively in the year of 2007-2008; the nitrogen apparent rates of Lankao aizao 8 which made wheat yeild achieved the highest yeild were 236 kg/hm~2 and 222 kg/hm~2 respectively at Wenxian and Lankao sites, while economically optimal N rates were 86 kg/hm~2 and 133 kg/hm~2 respectively in the year of 2007-2008;in the year of 2008-2009, the nitrogen apparent rates of Yumai 49-198 which made wheat yeild achieved the highest yeild were 194 kg/hm~2 and 249 kg/hm~2 respectively at Wenxian and Lankao sites, while economically optimal N rates were 165 kg/hm~2 and 223 kg/hm~2 respectively; the nitrogen apparent rates of Lankao aizao 8 which made wheat yeild achieved the highest yeild were 236 kg/hm~2 and 210 kg/hm~2 respectively at Wenxian and Lankao sites, while economically optimal N rates were 209 kg/hm~2 and 187 kg/hm~2 respectively.Considering the yeild and environmental effect comprehensively,the maximal nitrogen application rate should range from 90 kg/hm~2 to 200 kg/hm~2,the soil inorganic nitrogen concentration in 0-90cm soil layer in our case should not be exceeded 100-130kg/hm~2.