| In China,improving yields is a necessary way to improve total crop yields.However,in order to improve crop yields,excessive application of nitrogen fertilizer in agricultural production is common,which leads to serious waste of resources,ecological pollution and other problems.How to adopt suitable cultivation measures to improve the efficiency of nitrogen fertilizer utilization is an important scientific issue for high-yielding and efficient crop cultivation.Intercropping,as a planting pattern that can efficiently use resources and increase yield and efficiency,is one of the effective measures to improve land utilization and pursue sustainability.Based on the study of the effects of N fertilizer application and different spike type winter wheat cultivars on wheat growth and development,yield,and resource use efficiency under wheat∥pea intercropping system,this study selected winter wheat light spike type cultivar Xiaoyan 22（XY22）and heavy spike type cultivar Shuangda 1（SD1）from 2020-2022,using three gradients of N application:0 kg·hm-2（N0）,180 kg·hm-2（N1）and 240 kg·hm-2（N2）,and two different planting patterns:monoculture（M）and wheat-pea intercropping（I）constituting a three-factor interacting model,to measure the wheat yield and its components,grain quality,economic benefits,population growth and development,photosynthetic physiological characteristics,and nitrogen uptake and utilization indicators.Explore the response of wheat∥pea intercropping system production to wheat cultivars and nitrogen application,and provide theoretical references for the development of wheat∥pea intercropping planting pattern in Guanzhong region.The main results of this study are as follows:1.Nitrogen application and planting pattern significantly affected the yield and quality of winter wheat,and the yield levels of different spike type wheat cultivars responded differently to nitrogen application and planting pattern in terms of degree and response mode.Overall,high N application（N2）had a significant advantage over N0 and N1 in terms of yield and yield components;wheat-pea intercropping also had a significant positive effect in terms of yield and yield components compared to monocropping.The effect of N application and intercropping pattern on yield of different spike types of winter wheat mainly came from the fact that the number of spikes per unit area and the number of grains per spike factors were influenced by different treatments.Under different treatments,XY22 was able to achieve high yields of 7.62 t·hm-2 and SD1 was able to achieve high yields of 7.81 t·hm-2,both under high N intercropping conditions in the second year.However,under low N conditions（N1）,with the intercropping pattern,it was able to increase the yield and economic efficiency significantly to the high N treatment level,providing a theoretical basis for the N application and intercropping effect on production.2.Low N intercropping（N1I）is more advantageous for population construction and coordinated development of XY22,while high N intercropping（N2I）is more advantageous for SD1.The number of stem tillers in winter wheat populations tended to rise and then fall as the fertility period progressed,and overall,it would increase with the increase of nitrogen application.Intercropping system had a significant advantage over monocropping in terms of stem number,and the effect of cooperating with intercropping under high N was not significant,but the population size of winter wheat could be significantly increased by using intercropping cropping pattern under lower N application.In terms of plant height and spike length,both cultivars showed N1>N2>N0 for plant height response to N application and N2>N1>N0 for spike length;while plant height showed intercropping（I）>monocropping（M）under different planting patterns,with intercropping side rows（IS）being more advantageous in the first year and intercropping middle rows（IM）being more advantageous in the second year,and the difference in spike length was not significant.The effect of intercropping pattern was more significant for XY22 in low N and more significant for SD1 in high N.Leaf area index increased as fertility progressed,peaking around anthesis and gradually decreasing after flowering.Under different N application conditions,the leaf area index of both cultivars of winter wheat showed N2>N1>N0.Under different planting patterns,the overall leaf area index of both cultivars showed the highest in side row（IS）,which significantly increased by 8.71%and 12.54%for XY22 cultivars compared with M treatment and middle row（IM）.For SD1cultivar,side row（IS）significantly increased by 18.21%and 14.27%compared with middle row（IM）and M treatment.The intercropping of N application and planting pattern did not have significant effects on leaf area index of different wheat cultivars,and the overall performance of high N intercropping had significant advantages.In terms of photosynthetic performance,SD1 showed a stronger response to nitrogen fertilization than XY22 in the intercropping mode,and both high N application and intercropping mode had certain advantages in chlorophyll content accumulation and photosynthetic performance,which were more favorable to photosynthetic material production.3.Low N intercropping（N1I）was more advantageous for the accumulation and distribution of nutrients in XY22,while high N intercropping（N2I）was more advantageous for SD1.In terms of carbon and nitrogen accumulation,high N intercropping（N2I）had a significant advantage for both XY22 and SD1,and low N intercropping（N1I）was significantly higher than low N monocropping（N1M）and could approach or even exceed the level of high N monocropping（N2M）,but was still lower than the level of high N intercropping;in terms of the proportion of dry matter distribution in the spike at maturity,XY22 was more favored by low N intercropping side rows（N1IS）and high N intercropping side rows（N2M）.In terms of pre-flowering dry matter transfer efficiency,XY22 had the highest performance in the low N intercropping side row（N1IS）and the high N intercropping side row（N2IS）,while SD1 had the highest performance in the high N intercropping side row;in terms of pre-flowering dry matter transfer contribution to the seeds,XY22 showed a higher overall performance in the low N（N1）than in the high N（N2）,with no significant difference between the low N There was no significant difference among different planting patterns,and SD1 showed that high N（N2）was higher than low N（N1）overall,with the highest increase in the intercropped side rows;in terms of nitrogen spike fraction and nitrogen translocation at maturity,both XY22 and SD1 showed the advantage of high N intercropping,with the highest performance in the side rows;in terms of nutrient organ contribution to seeds,XY22 showed low N while SD1 showed the highest difference among treatments.The difference was not significant.4.For both XY22 and SD1,low N intercropping（N1I）could significantly improve the nitrogen uptake efficiency of different cultivars of winter wheat,and both cultivars of wheat performed best in the low N intercropping side row（N1IS）.The experiment showed that for XY22 and SD1 with different N applications,the low N（N1）treatment significantly increased N fertilizer partial productivity（Nf P）and N uptake efficiency（Nup E）,significantly decreased N harvest index（NHI）,somewhat but not significantly increased N utilization efficiency（NUE）,and N agronomic utilization efficiency（NAE）and apparent recovery（RE）compared with the high N（N2）treatment.did not vary significantly.There were significant effects of different planting patterns on N fertilizer bias productivity,N uptake efficiency,NUE and apparent recovery rate of winter wheat,specifically showing a trend that intercropped side rows were significantly higher than monocropping and intercropping middle rows.Therefore,low nitrogen intercropping（N1I）improves the nitrogen absorption and utilization efficiency of winter wheat,which is beneficial for efficient crop production and economic benefits.This experiment adopts a reasonable and effective cultivation mode of wheat and beans,revealing that winter wheat can achieve high yield and efficiency standards through inter group regulation and improved nutrient utilization under intercropping mode,providing a theoretical basis for effectively improving farmers’income and green sustainable agricultural development. |
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