Effect Of Urea Application Rate On Yield And Quality Of Different Soybeans

Nitrogen is very important for soybean growth.It is controversy whether additional nitrogen fertilizer needed or not in soybean production as soybean rhizobium can fix nitrogen. This experiment was carried out by using twelve soybean cultivars from different regions in 2006 and 2007.And the cultivars were divided into three groups:current Ohio cultivar, current Liaoning cultivar and old Liaoning cultivar.Urea fertilizer(0,100,200 kg/hm~2) was topdressed at soybean seedling stage.The physiology and biochemistry of leaf, agronomic characteristics,yield and quality were measuredfor the effect of nitrogen on soybeans from different regions.It can provide academic theories for higher yield,better quality,and more efficiency production of soybeans.The results were as follows:1.The effect of nitrogen on photosynthetic traits for soybean cultivars from different regionsCompared with the no fertilizer treatment,total content of chlorophyll of current Ohio cultivar at podding stage was improved when 100kg/hm~2 urea was fertilizered,Total content of chlorophyll of three groups soybean cultivar at blooming stage was significant improved when 100kg/hm~2 urea was fertilizered.Total content of chlorophyll of current Liaoning cultivar and old Liaoning cultivar was significant rised at podding stage.The LAI of current Ohio cultivar at blooming stage increased as the level of nitrogen fertilizer ascending.The LAI increased with the level of nitrogen fertilizer ascending for current Liaoning cultivar at blooming and podding stages.The LAI was significant improved for current Ohio cultivar and old Liaoning cultivar at podding stage when 100kg/hm~2 urea was fertilizered.The LAI was significant rised for old Liaoning cultivar at blooming stage when 200kg/hm~2 urea was fertilizered.The LAI of soybean cultivar will improve with the level of nitrogen fertilizer ascending.The leaf net photosynthesis rate was improved in the treatment of 100kg/hm~2 urea for current Ohio cultivar and current Liaoning cultivar at blooming and podding stages.The leaf net photosynthesis rate of old Liaoning cultivarincreased with the level of nitrogen fertilizer ascending at blooming stage.The leaf net photosynthesis rate was improved in the treatment of nitrogen fertilizer for current Ohio cultivar and current Liaoning cultivar at grain filling stage.2.The effect of nitrogen on physio-biochemical characters for soybean cultivars from different regionsThe effect was different for nitrogen treatment on glutamine synthetase activity for soybean cultivars from different regions.There was some different reaction for nitrogen at different growth stages.The glutamine synthetase activity will be reduced for current Liaoning cultivar and old Liaoning cultivar at blooming stage.The glutamine synthetase activity will be arised at podding stage and grain filling stage in the treatment of 100kg/hm~2 nitrogen fertilizer.The glutamine synthetase activity wil be improved at grain filling stage in the treatment of 100kg/hm~2 nitrogen fertilizer.The glutamine synthetase activity of old Liaoning cultivar lower and lower with the nitrogen level ascending at podding stage and grain filling stage.The glutamine synthetase activity of current Liaoning cultivar will be reduced with the nitrogen level ascending at podding stage.The nitrate content of leaves was increased with the level of nitrogen fertilizer ascending for three groups soybean cultivar at blooming stage.The ammonium content of leaves was raised in the treatment of nitrogen fertilizer for three groups soybean cultivar at blooming, podding and grain filling stages.The SOD activity was added in the treatment of 100kg/hm~2 nitrogen fertilizer for current Ohio cultivar and old Liaoning cultivar at blooming stage.The SOD activity increased in the treatment of 100kg/hm~2 nitrogen fertilizer for current Liaoning cultivar and old Liaoning cultivar at podding stage.The SOD activity was reduced in the treatment of 100kg/hm~2 nitrogen fertilizer for current Liaoning cultivar at grain filling stage.The SOD activity of current Liaoning cultivar increased with the level of nitrogen fertilizer at blooming stage.The SOD activity of current Ohio cultivar increased with the level of nitrogen fertilizer ascending at podding stage.But the SOD activity of current Ohio cultivar and old Liaoning cultivar decreased in the treatment of nitrogen fertilizer at grain filling stage.The POD activity of soybean cultivar increased with the level of nitrogen fertilizer ascending at blooming stage.The POD activity of current Ohio cultivar and old Liaoning cultivar improved with the level of nitrogen fertilizer ascending at podding stage.But the POD activity of current Ohio cultivar and old Liaoning cultivar decreasedin the treatment of nitrogen fertilizer at grain filling stage.The CAT activity of soybean cultivar increased with the level of nitrogen fertilizer ascending at blooming stage.The CAT activity of current Ohio cultivar and old Liaoning cultivar increased with the level of nitrogen fertilizer ascending at podding stage.The CAT activity of old Liaoning cultivar improved in the treatment of 100kg/hm2 urea fertilizer than 0kg/hm~2 urea fertilizer at podding stage.At the same time,the CAT activity of three groups soybean cultivar rised at grain filting stage.The soluble sugar content in leaves of current Ohio cultivar and current Liaoning cultivar significantly rised in the tteatment of 200kg/hm~2 urea fertilizer than 0kg/hm~2 urea fertilizer at blooming stage.The soluble sugar content in leaves of old Liaoning cultivar improved with the level of nitrogen fertilizer adding at blooming stage.The starch content in leaves of current Ohio cultivar decreased with the level of nitrogen fertilizer adding at blooming stage.But it is inverse for old Liaoning cultivar.The starch content in leaves of old Liaoning cultivar improved with the level of nitrogen fertilizer adding at blooming stage.The starch content in leaves of current Liaoning cultivar significantly rised in the treatment of 200kg/hm~2 urea fertilizer than 0kg/hm~2 urea fertilizer at blooming stage. The starch content in leaves of three group soybean cultivars from different regions decreased in the treatment of nitrogen fertilizer at podding stage. The invertase activity in leaves of three groups soybean cultivar from different regions significantly improved in the treatment of nitrogen fertilizer at blooming stage and podding stage.The soluble protein content in leaves of soybean cultivar improved in the treatment of nitrogen fertilizer at blooming,podding and grain filling stage.3.The effect of nitrogen on agronomic characteristics,yield and quality for different regions soybeanThe plant height,branches and the pods per plant of soybean cultivar improved in the treatment of nitrogen.The nodes of main stem for three groups soybean cultivars rised in the treatment of 100kg/hm~2 nitrogen fertilizer.The height of lowest pod of current Ohio cultivar and current Ohio cultivar reduced in the treatment of 100kg/hm~2 nitrogen fertilizer.The ratio of seed and stem for current Ohio cultivar and current Ohio cultivar improved in the treatment of nitrogen fertilizer.The yield increased by 10.61%and 1.63%for current Ohio cultivar and old Liaoning cultivar in the treatment of 200kg/hm~2 nitrogen fertilizer respectively.The yield increased by 10.47%for current Liaoning cultivar in the treatment of 100kg/hm~2 nitrogen fertilizer.The seed protein content of three groups soybean cultivars imcreased with the level of nitrogen fertilizer ascending.But the seed oil content of current Ohio cultivar decreased in the treatment of nitrogen fertilizer.The increase of seed oil content of was 0.35%and 1.10%for current Liaoning cultivar and old Liaoning cultivar in the treatment of 100kg/hm~2 nitrogen fertilizer respectively.The total content of protein and oil increased in the treatment of nitrogen fertilizer for three group soybean cultivars.Compared the endure reaction on fertilizer in three groups soybean cultivars,current Ohio cultivar was the best,followed by current Liaoning cultivar,old Liaoning cultivar was poor.This indicated that after decades of genetic improvement,current Ohio cultivar was better than current Liaoning cultivar,and resistant and adaptability of current Ohio cultivar is better than current Liaoning cultivar.Therefore,it can be use experience of other countries in the breeding process for reference,accelerating the process of improvement on our country's soybean cultivars,improving fertilizer tolerability and adaptation,thereby enhance the yield of our country's soybean.