The Effect Of Alfalfa And Winter Wheat Intercropping System On Soil Water And Nutrients

The combination of planting and breeding is conducive to maintaining sustainable production capacity of farmland and achieving stable and high yield of crops.The study of intercropping system is not only conducive to the development of intensive agriculture,but also can systematically study the overall situation of coordinated development of farmland ecosystem.Although intercropping has been strongly supported and widely used by the state,there are few studies on the intercropping of perennial legumes and Gramineae in the main wheat producing areas.The main purpose of this study is to observe the changes of soil moisture,soil nutrients,crop growth and yield,interspecific competitiveness between different treatments under planting patterns with different proportions of alfalfa and winter wheat,so as to provide guidance for crop growth,agricultural production and sustainable development in this area.This study was conducted at the National Field Science Observation and Research Station of Shangqiu Agricultural Ecosystem in Henan Province.The experiment was divided into two modes: row intercropping and belt intercropping,Through field observation sampling and laboratory experiment analysis,the soil moisture,soil nutrients,crop growth and yield,interspecific competitiveness and other indicators of different treatments of the two planting modes were analyzed,and the observation and analysis results were processed by SPSS software.The main results of this study are as follows:(1)From the point of view of soil moisture,whether intercropping or strip intercropping,compared with single-seeding system,intercropping can preserve soil moisture,improve soil moisture content,and benefit the growth of winter wheat.In intercropping system,intercropping showed higher soil water storage consumption,total water consumption and soil water use efficiency than strip intercropping.Intercropping was a more ideal planting mode.3-XM model was the best planting mode in inter-row intercropping.Soil water use efficiency of X-3 increased by 5.31% and 21.62% compared with X-1 and X-2 treatments,and that of M-3 increased by 41.93% and 23.28% compared with M-1 and M-2 treatments respectively.(2)From the point of view of soil nutrients,since the alfalfa-winter wheat intercropping,with the deepening of alfalfa root system in the underground,the safety net formed by the intersection of alfalfa roots and wheat roots,which intercepted soil nutrients.At this time,the safety net is equivalent to a "nutrition pump" to provide sufficient nutrients for crops.The change of soil organic matter and pH between tillage model treatments was opposite.Soil organic matter decreased with the increase of soil depth,while soil alkalinity increased with the increase of soil depth.Soil in 0-100 cm layer was alkaline.In terms of total nitrogen and available nitrogen,alfalfa promoted nitrogen uptake and utilization by wheat in surface soil.After a winter wheat growing season,soil nitrogen content was significantly reduced,and the soil was in a state of nitrogen deficiency.Next,if winter wheat was planted,nitrogen fertilizer should be supplemented in time.After intercropping,the nitrogen fertility of 60-100 cm soil layer was improved,and the available nitrogen content of intercropping was higher than that of single-seeding system,which avoided the problem of nitrogen loss in deep soil of conventional wheat fields.After alfalfa-winter wheat intercropping,the activity of phosphorus in root layer(0-100cm)was increased,and the consumption of phosphorus was increased.The application of phosphorus fertilizer should be increased in production practice.Although alfalfa consumes a lot of potassium in the surface soil,the content of potassium in the soil is always in surplus,so it can be applied less or even without potassium fertilizer.(3)In terms of crop growth and yield,the descent rate of SPAD value of alfalfa and winter wheat decreased and protein content of wheat grain increased after intercropping;As for plant nitrogen,intercropping was higher than strip intercropping.The 1-XM planting mode(alfalfa-winter wheat mixed sample)showed more obvious advantages.In the two years,the nitrogen acquisition was 0.45%,5.03%,12.19% and 82.19% higher than that of 2-XM,3-XM,CK-X and CK-M respectively.In terms of biological yield,inter-row intercropping is higher than belt Intercropping.In the inter-row intercropping mode,the yield advantage of3-XM mode was more obvious during the two-year trial period.Since the second year ofAlfalfa planting,alfalfa has entered a high yield period,and the intercropping system showed higher yield advantage and land use efficiency than the single-seeding system.Under 3-XM planting mode,alfalfa covers the least area and has the highest dry matter yield.This planting mode not only guarantees dry matter yield,but also enriches species diversity.(4)From the perspective of interspecific competitiveness between alfalfa and winter wheat,alfalfa intercropping showed higher occupancy and competition ratio,and alfalfa had stronger occupancy in inter-row intercropping.Inter-row intercropping with 3-XM had the highest average invasiveness to wheat.The invasiveness of 3-XM was 29.74% and 13.26%higher than that of 1-XM and 2-XM respectively.