Effect Of Different Nitrogen Fertilizers On The Yield And Quality Of Soybean

Soybean is not only the grain and cash crop,but also the raw material of industry.It is an important resource of plant-protein and edible-oil.In recent years China has changed from soybean-exported country to soybean-imported country.In the year 2005-2006 China imported 28.27M tons of soybean--1.66 times of itself production(10M tons).Soybean is the only staple crop that is hard up.In China the study on soybean nutrition and physiology dropped behind the developed country. Nitrogen is the main factors that influence the soybean yield.While the increasing input of N fertilizer and application without reason result in the low fertilizer use efficiency and benefit and environment pollution.Through the field experiment the test was carried out to study the effect of different N fertilizer on the yield and its quality of soybean.Four treatments of different fertilization were setup.Treatmentl was urea;treatment2 was ammonium bicarbonate;treatment3 was half urea and half ammonium bicarbonate(according to pure N),and treatment4 was CK.In each treatment 52.2 kg·hm^-2 pure N were used.Three replications were setup.The main results are as follows:1.Ammonium bicarbonate and urea increased the bulk and number of root nodules significantly,the bulk and number of root nodules of Ammonium bicarbonate treatment was 13.89%and 69.3%more than urea treatment separately.2.At flowering and pod-setting and seed-filling stage the chlorophyll in soybean leave of Ammonium bicarbonate treatment was more than urea treatment.At flowering stage the difference was not significant,while the number increased 3.58%. There was no significant difference of photosynthetic index such as rate,stomatal conductance,Intercellular CO2 concentration between the four treatments,while the stomatal conductance and Intercellular CO2 concentration between treatments have the same trend,that was Ammonium bicarbonate＞Ammonium bicarbonate + urea＞urea＞CK.3.Ammonium bicarbonate and urea could increase the plant height obviously, and Ammonium bicarbonate increased 0.85%than urea.Ammonium bicarbonate could increase significantly the number of pods and 100-seed weight,and the trend between treatments was Ammonium bicarbonate＞urea＞Ammonium bicarbonate + urea＞CK.Ammonium bicarbonate could increase the yield of soybean significantly,while the difference was not significant compared with urea,though number was 14.32%more than the latter.4.The inferior appearance quality of ammonium bicarbonate,urea and Ammonium bicarbonate + urea decreased 73.56%,61.93%,69.21%than CK separately.Ammonium bicarbonate could obviously increase the crude protein and water-soluble protein,and the increasing rate was 4.14%(dry),5.02%(dry) separately compared with CK.N fertilization could not increase the oil content and index of soluble N.