Effect Of Nitrogen Application Amount And Ratio On Grain Yield And Nitrogen Absorption And Utilization Efficiency Of The Different Special Wheat

The experiment was conducted with the clay of Gaoyou City (Xiejia Town) and sandy loam of experimental farmland in Yangzhou university from 2001 to 2003. The soil had middle lever fertilizer and the pre-planted crop was rice. The mid-gluten wheat Yangmai 11 and the weak-gluten wheat Ningmai 9 were used to study effect of Nitrogen Application Amount and Ratio on Grain Yield and Nitrogen Absorption Efficiency. The results were abstracted as followings:(1) The nitrogen application amount and ratio had a quadratic curve correlation with grain yield of Yangmai 11 and Ningmai 9 in two trail places. The highest yield of two varieties all used 15kg/667m2 of N application amount. The optimal range of nitrogen ratio with higher Grain yield was from 7:3 to 5:5 in two trial places. The ratio of highest yield of two varieties was 6:4 in Gaoyou for two years while 6:4 in the first year and 5:5 hi the second year in Yangzhou. Grain yield of Ningmai 9 was higher than Yangmai 11 in the same place. Grain yield of Yangzhou was higher than Gaoyou with the same varieties.(2) Population time-course tiller number, maximal LAI and dry matter accumulation of Yangmai 11 and Ningmai 9 enhanced along with the increasing of N application amount. Ratio of fertile tillers was higher with N application amount from 15 to 18.75kg/667m2. Dry matter accumulation after blooming was higher with N application amount from 11.25 to 18.75kg/667m2.The relationship between ratio of fertile tillers of Yangmai 11 and Ningmai 9 and ratio of topdressing N during jointing stage could be expressed a quadratic curve in Gaoyou, while it increased with ratio of topdressing N in Yangzhou. The ratio of fertile tillers of two varieties was higher with ratio from 6:4 to 5:5 in Gaoyou while from 6:4 to3:7 in Yangzhou. The maximal LAI and dry matter accumulation after blooming of two varieties had a quadratic curve correlation with ratio of topdressing N in two trail places. The maximal LAI of two varieties was higher with ratio from 8:2 to 5:5 in Gaoyou while from 8:2 to 6:4 in Yangzhou. The dry matter accumulation after blooming was higher with ratio from 6:4 to 5:5 in Gaoyou while from 6:4 to 4:6 in Yangzhou. The ratio of fertile tillers and maximal LAI and dry matter accumulation after blooming of Ningmai 9 was higher than Yangmai 11 in the same place. The three indexes of Yangzhou was higher than Gaoyou with the same varieties.(3) High N application amount could promote N absorption amount per 100kg grain of the two kinds of wheat in two trial places. The N absorption amount per 100kg grain of Yangmai 11 was higher than Ningmai 9. N utilization efficiency of two varieties reduced with the increase of N application amount in two trial places. N utilization efficiency of Yangmai 11 was higher than Ningmai 9 with N application amount from 3.75 to 15kg/667m2 in the same trail place. N utilization efficiency of Yangzhou was higher than Gaoyou with the same varieties.The N accumulation amount per 100kg grain of Yangmai 11 and Ningmai 9 raised with the increasing of ratio of topdressing N during jointing stage in two trail places while the highest with 3:7 treatments. N accumulation amount per 100kg grain of Yangmai 11 was higher than Ningmai 9 in the same trail place, and N accumulation amount per 100kg grain of Gaoyou was higher than Yangzhou with same varieties. N utilization efficiency increased with the increasing of ratio of topdressing N in the first, then decreased. It was the highest with 6:4 of basic to topdressing in Gaoyou, while it was the highest with 5:5 treatments in Yangzhou. N utilization efficiency of Yangmai 11 was higher than Ningmai 9 with ratio from 6:4 to 3:7 in Gaoyou and all treatments in Yangzhou in the same trail place. N utilization efficiency of two varieties in Yangzhou was higher than in Gaoyou.In sum, these results showed that the highest grain yield and the highest nitrogen utilization efficiency could be achieved in central region of Jiangsu by the optimal treatment of 15kg/667m2 of N application amount with t...