Effects Of Different Nitrogen Rates On Nitrogen Absorption And Utilization,yield And Quality In Forage Maize And Rape Intercropping

Based on the development direction of sustainable and intensive agriculture,constructing a reasonable forage grass intercropping planting mode and developing matching nitrogen fertilizer high-efficiency application methods are important problems to be solved in the rapid development of animal husbandry in Inner Mongolia.The experiment was conducted in the modern agricultural science and technology center of tumed Left Banner,Inner Mongolia in 2019 and 2020.The feed corn variety(Yidan 76)and feed rape variety(Siyou 2)were taken as the research objects.The two factor randomized block design was adopted.The factors of planting mode included three modes:corn monoculture,rape monoculture and corn rape intercropping.The factors of nitrogen application included three levels:no nitrogen application(N0),nitrogen application rate of120kg/hm~2(N1)and nitrogen application rate of 210kg/hm~2(N2).The effects of Nitrogen Application on forage yield,nutrient quality,soil physical and chemical properties and nitrogen use efficiency under different planting patterns were studied,and the advantages of interspecific competition on yield increase and nitrogen use in intercropping were clarified,so as to determine the appropriate nitrogen application rate for forage maize and rape Intercropping in plain irrigation area.(1)The LER of Forage Maize and rape intercropping model in tumechuan,Inner Mongolia was 1.08～1.14,and the nitrogen absorption equivalent ratio was 1.17～1.30,which had a high degree of land intensive utilization.The fresh grass yield of each treatment increased with the increase of nitrogen application rate.The fresh grass and dry grass yield of N2 intercropping maize and rape were the highest,but the fresh grass and dry grass yield of N1 intercropping maize were increased by 16.81%and 22.17%(p<0.05)compared with that of monoculture.There was no significant difference between the fresh grass yield of intercropping rape and that of monoculture under each nitrogen application rate(p>0.05),but the dry grass yield of N1 intercropping rape was increased by 11.83%compared with that of monoculture.(2)Intercropping and nitrogen application can improve the nutritional quality of Forage Maize and rape.The crude protein content of plants increases significantly with the increase of nitrogen application.Nitrogen application can significantly reduce ADF and NDF of forage plants,and increase RFV.Intercropping has significantly affected the forage dry matter intake rate,dry matter digestibility and total metabolic energy yield,making the forage quality from energy to palatability improved.(3)Compared with monoculture,intercropping with forage maize and rape can improve the absorption of soil nitrogen,and all of them increase with the increase of nitrogen application.The nitrogen content and nitrogen absorption of maize plants are higher than that of rape as a whole.The nitrogen content and nitrogen absorption of N1intercropping maize plants are the largest compared with monoculture.Intercropping can significantly improve crop nitrogen use efficiency.Within two years,N1 intercropping maize has the highest PEP,AEN and ner,and the NER of N1 intercropping maize is29.32%higher than that of N2,and the highest increase range of N1 intercropping maize is22.19%,36.76%and 57.67%(p<0.05)compared with monoculture maize.The PEP and AEN of maize treatment are significantly higher than that of corresponding rape treatment;Compared with monoculture,NER of N1 intercropping rape was increased by 10.95%,and that of N2 intercropping rape was increased by 26.32%.(4)Compared with monoculture,forage maize rape intercropping can improve the absorption of soil nitrogen.The nitrogen content of maize plant is higher than that of rape as a whole.The nitrogen content and nitrogen absorption of N2 intercropping maize are the highest,which increase with the increase of nitrogen application.The nitrogen content of intercropping maize was higher than that of monoculture,and the nitrogen content and nitrogen absorption of N1 intercropping maize were the largest,However,in 2020,the nitrogen content of rape plants decreased by 9.51%on average compared with that of monoculture,resulting in the overall decrease of nitrogen uptake of rape in 2020 compared with that in 2019,and there was no significant difference between intercropping rape and monoculture under each nitrogen application treatment(p>0.05).(5)Compared with rape,maize is the dominant crop in this intercropping system.Nitrogen application strengthens the nitrogen competitiveness of maize,and the competitive advantage of maize was the strongest under N1(120kg/hm~2).(6)The increase of nitrogen application rate can significantly increase the accumulation of soil nitrate nitrogen.Under each nitrogen application rate,the accumulation of soil nitrate nitrogen in oil menu was higher than that in corn in two years,and the highest was in N2 rape monoculture,which reduced the accumulation of soil nitrate nitrogen.Under N1,the accumulation of soil nitrate nitrogen in intercropping was significantly lower than that in rape monoculture(p<0.05),which decreased by28.22%～30.70%in two years.(7)The net income of maize rape intercropping reached the highest(632.07～681.78yuan/mu),and the currency advantage index reached the highest(44.26～74.30)at120kg/hm~2.