[Main interspecific competition and land productivity of fruit-crop intercropping in Loess Region of West Shauxi].

Taking the four typical fruit-crop intercropping models,i.e.,walnut-peanut,walnut-soybean,apple-peanut,and apple-soybean,in the Loess Region of western Shanxi Province as the objects,this paper analyzed the crop(peanut and soybean) photosynthetic active radiation(PAR),net photosynthetic rate(Pn),yield,and soil moisture content.Comparing with crop monoculture,fruit-crop intercropping decreased the crop PAR and Pn.The smaller the distance from tree rows,the smaller the crop PAR and Pn.There was a significantly positive correlation between the Pn and crop yield,suggesting that illumination was one of the key factors affecting crop yield.From the whole trend,the 0-100 cm soil moisture content had no significant differences between walnut-crop intercropping systems and corresponding monoculture cropping systems,but had significant differences between apple-crop intercropping systems and corresponding monoculture cropping systems,indicating that the competition for soil moisture was more intense in apple-crop intercropping systems than in walnut-crop intercropping systems.Comparing with monoculture,fruit-crop intercropping increased the land use efficiency and economic benefit averagely by 70% and 14%,respectively,and walnut-crop intercropping was much better than apple-crop intercropping.To increase the crop yield in fruit-crop intercropping systems,the following strategies should be taken:strengthening the management of irrigation and fertilization,increasing the distances or setting root barriers between crop and tree rows,regularly and properly pruning,and planting shade-tolerant crops in intercropping.