Effect Of Different Forage Planting Patterns On Physical And Chemical Properties Of Soil And Forage Yield In Degraded Farland

Under dry farming conditions,using leguminous forage Medicago sativa CV.Aohan and gramineous forage Elymus sibiricus L.as materials,field and indoor experiments were performed here.Three different planting patterns except the control were designed in this paper: Single-seeding Medicago sativa CV.Aohan(Ms),single-seeding Elymus sibiricus L(Es)and Intercropping of these two forage(In),with leisure treatment as control(Ck).The aim of the experiment is to study the effects of different forage planting patterns on degraded farmland soil physical traits,soil chemical traits,dry matter accumulation of forage plants,and forage yield and economic benefits,in order to screen out the optimal planting pattern of pasture,and provide theoretical and technical support for the improvement of degraded farmland and sustainable land use.The results are as follows:(1)Effects of different forage planting patterns on soil physical properties.With the increase of planting years,soil bulk density decreased,soil total porosity and stability aggregate content increased,and water content fluctuated with seasonal rainfall.After planting for two years,as compared with CK treatment,the soil watercontent of different planting modes decreased in two mowing periods,in Es goups decreased by 59.66% and 17.81% respectively.However,in In group the soil water content increased both in seedling and vegetative growth periods.Both MS and In groups increased the content of soil stable aggregates.Therefore,In group has positive effect on alleviating wind erosion and desertification,improving soil water retention of degraded farmland.(2)Effects of different forage planting patterns on soil chemical properties.With the increase of planting years,soil pH value and available phosphorus content first decreased and then increased;whereas organic matter,available potassium,total nitrogen,total potassium content increased.Compared with leisure land,soil organic matter content of Ms,Es and In increased significantly by56.53%,49.38% and 48.01% in the first year;available potassium content increased significantly by 66.92%,56.15% and 95.03%;alkali-hydrolyzed nitrogen and total nitrogen content increased;pH value decreased;and soil total phosphorus and total potassium content increased in Ms and In groups.In the second year,the alkali-hydrolyzed nitrogen content of Ms,Es and In decreased by 20.91%,24.37%and 40.05% in 10-20 cm soil layer,and the available phosphorus content decreased by38.92%,32.19% and 39.65% in 20-40 cm soil layer.The soil organic matter and total potassium content increased,while the available phosphorus and available potassium content decreased;The contents of available potassium in the soil of MS and Es decreased significantly,and the pH of 0-20 cm decreased;the content of organic matter in In and Ms groups increased significantly.The total phosphorus contentdecreased significantly in the 20~40cm soil layer;while In and Es significantly increased the soil pH of the 20~40cm soil layer.(3)Effects of different forage planting patterns on the accumulation of dry matter in forage.Compared with Es,in the first and second years treatment,the plant height In,s Elymus sibiricus L(In-Es)planting increased by 8.93% and 17.68%,the ratio of stem to leaf increased by 46.89% and 20.35%,and the dry weight of stems,leaves and aboveground plants did not differ significantly.Compared with Ms,In,s Medicago sativa CV.Aohan plant(In-Es)height decreased by 21.37% in the first year,but slightly increased in the second year.Compared with MS,the dry weight of stem,leaf and aboveground plants in the first year showed no significant changes from that of Ms,but those decreased by 37.77%,47.60% and 42.05% respectively in the second year.(4)Effects of different forage planting patterns on forage yield and economic benefits.With the increase of planting years,the yield of forage grass hay increased.The total hay yield in two years showed that Ms production was significantly higher than In and Es,which was 28.04% and 53.47% higher respectively.Furthermore,the yield of In significantly increased by 19.86%compared with that of Es.Based on the field experiment results of the two-year pasture planting pattern on physical and chemical properties of the soil and pasture yield of degraded farmland,it was found that the impact of planting patterns on soil physical and chemical properties and yield was significant.After omprehensive consideration ofcultivated land quality improvement effect and output economic benefit index,we preferred to recommend MS or In planting model.