黄土残塬区不同种植类型下耕地土壤肥力与经济效益耦合关系研究

Study on the coupling relationship between soil fertility and economic benefits of cultivated land under different planting types in loess residual tableland

塬地农田作为黄土高原地区发展种植业的最佳区域,近年来由于人类对农业种植类型的不合理选择,使得该区域土壤保肥持水的水平降低,且已对作物生长及农业经济发展产生严重威胁,故本文旨在研究该区域不同种植类型下耕地土壤肥力和经济效益耦合关系,从而选取合适的种植类型。本研究选取晋西南塬地四种典型样地类型(玉米、棉花、马铃薯、荒地)为研究对象,对2019年、2020年全生育期(3—10月)土壤肥力及产值产量进行测定,基于实验数据采用耦合协调度模型综合分析各作物种植下肥力、经济效益状况及耦合协调度。结果表明:(1)不同种植类型下土壤肥力有显著差异,其中马铃薯种植下土壤肥力最高;(2)不同生育期土壤肥力变化有异,除土壤含水量外各肥力指标在快速发育期含量最高而生长中期显著降低,土壤含水量在快速发育期含量最低;(3)各土壤肥力指标含量在20—40 cm土层较高,土壤含水量在0—20 cm土层含量较低;(4)各种植类型下经济效益排序为棉花>马铃薯>玉米>荒地,其中棉花经济效益分别为马铃薯、玉米和荒地的1.17倍、1.36倍和3.40倍;(5)马铃薯种植下耦合协调度最高,棉花和玉米次之,荒地最低。综上,马铃薯种植对肥力改善具有重要意义,而以经济创收为目的的优势种植类型为棉花。农业的可持续发展要求经济创收和地力保护相协调,本研究表明马铃薯为晋西南黄土残塬区兼顾经济增长和农业环境保护的最佳种植类型,应积极推广种植。以上各作物类型种植下在快速发育期应及时灌溉以减小水分对肥力改善和作物产量的限制。该研究对黄土残塬区耕地种植类型的合理选择、科学施灌及促进农业可持续发展等具有重要意义。

Background,aim,and scope Tableland farmland was one of the best area for the development of planting industry in the Loess Plateau.The soil fertility and water retention in the tableland farmland had been reduced and posed a serious threat to crop growth and agricultural economic development due to the unreasonable selection of agricultural planting types in recent years.Therefore,this paper aims to study the coupling relationship between soil fertility and economic benefits of cultivated land under different planting types in the region,so as to select appropriate planting types.Materials and methods Four typical lands(corn,cotton,potato,and abandon land)in southwest Shanxi were selected as the research objects,and the soil fertility,output value and yield during the whole growth period(March—October)in 2019 and 2020 were measured.The coupling coordination degree model was used to comprehensively analyzed the fertility,economic benefit and coupling coordination degree of each crop based on the experimental data.Results The results showed that:(1)there were significant differences in soil fertility under different planting types,among which the soil fertility under potato planting was the highest.(2)The changes of soil fertility in different growth stages were different.Except for soil water content,all of the fertility indexes were the highest in the rapid development period and significantly decreased in the middle growth period,and soil water content was the lowest in the rapid development period.(3)When compared among the soil layers,soil fertility indexes content was the highest in 20—40 cm soil layer,and soil water content was the lowest in 0—20 cm soil layer.(4)The order of economic benefits under different planting types was cotton>potato>corn>abandon land,in which the economic benefits of cotton were 1.17,1.36,and 3.40 times that of potato,maize and abandon land,respectively.(5)The coupling coordination degree was the highest under potato planting,followed by cotton and maize,and the lowest in abandon land.Discussion(1)The soil water content and nutrient content were the highest under potato planting when compared with the other crops,because the soil rhizosphere with strong soil enzyme activity and high nitrogen fixation efficiency which could provide a good nutrients environment.In addition,potato stems and leaves growing close to the ground had a positive effect on reducing soil water content evaporation.The low content of corn land may be due to the high demand for nutrients by its own physiological structure and growth habits,and it was also due to the shallow planting and fertilization of corn in recent years and the large loss of surface water and nutrients due to evaporation,wind invasion and leaching.(2)Cotton planting had the highest economic benefits when compared with the other crops,mainly because of its high economic value and less substitutes.As China’s largest food crop,corn planting has lower economic benefits mainly because of its lower economic value than other crops and weak processing,transformation and value-added ability.Conclusions Based on the above results,potato planting had best significance to improve of soil fertility,while the dominant planting type for the purpose of economic income generation was cotton.The sustainable development of agriculture required the coordination of economic growth and soil fertility protection.This study found that potato planting should be balance the economic growth and agricultural environmental protection in loess residual tableland in southwest Shanxi.Recommendations and perspectives In order to reduce the limitation of water on fertility improvement and crop yield,irrigation should be carried out in time during the rapid development period under every crop types.This study had important meaning to the reasonable selection of cultivated land planting types,scientific irrigation and the promotion of agricultural sustainable development in loess residual tableland.