Research On The Changes Of Yield,Carbon,Nitrogen And Phosphorus In The Wheat-soybean And Wheat/Maize/Soybean Systems Under Different Nitrogen Level

It is the major system of dry land crops which is the wheat/maize/soybean anniversary system in sichuan,research the output and the absorb of carbon,nitrogen and phosphorus nutrient, known that the change of output and C/N,C/P, It is Important significance for scientific management of nutrients and high output and efficiency in the system of wheat/maize/soybean.The job research adopts the field experiment,5 dosage of nitrogen (N) levels(For wheat:0,60,120,180,240 kg/hm2,Marked as WN1，WN2, WN3, WN4, WN5; For corn:0,97.5,195,292.5,390kg/hm2,Marked as MN1, MN2, MN3, MN4, MN5; soybean have nofertilizer,Marked as SN1, SN2, SN3, SN4,SN5),research on the output,Distribution of dry matter accumulation,nutrient content which is carbon,nitrogen and phosphorus and the change of C/N and C/P,Compared the differences of output and nutrient uptake in which the solo/inter-cropping wheat,the solo/inter-cropping soybean,the wheat-soybean and the system of wheat/jade/bean.The main results were as follows:(1)Wheat,maize and soybean plant height increased as nitrogen increased,the dry matter accumulation and the output of grain which the wheat and maize is increased as nitrogen increased,the output and dry matter accumulation have the trend increase to reduce in soybean,the treatment of N3 is maximum.Inter-cropping wheat’s dry matter accumulation and output is more than solo-cropping about 30.9%andl6.9%. inter-cropping soybean is lower than solo-cropping soybean about 8.2%and9.8% by the dry matter accumulation and grain output.Whole wheat characterized by inter-planting advantages, show the inter-planting soybean disadvantage.(2)Wheat,maize and soybean N content increased as nitrogen increased,the maximum is in N4 and N5. wheat and maize C content increased as nitrogen increased,the maximum is in WN3 and MN3.It prove that the moderate amount of nitrogen for wheat and maize is make for the absorption of carbon, excessive nitrogen can hinder the absorption of carbon,The carbon content of soybean is decreased as nitrogen increased,show that nitrogen have inhibitory effect on soybean carbon absorption.(3)Wheat,maize and soybean C/N reduced as nitrogen increased,C/P increased as nitrogen increased.Solo-cropping wheat is higher than inter-cropping in which the C/N and C/P. Explain inter-planting wheat nitrogen and phosphorus is more efficient; The no nitrogen treatment of soybean is show that the characteristics of nitrogen deficiency.(4)Anniversary of output,the absorption of nutrient accumulation amount and nitrogen accumulation rate in wheat/maize/soybean is higher than wheat-soybean.It is higher 24.9% in output,It higher 99.4% in nitrogen accumulation rate.