Effect Of Protected Seeding On The Yield And Quality Of Forage With Different Utilization Types In Alpine Region

Sanjiangyuan has an important function of water conservation,and it is the ecological barrier of ecological environment security and regional sustainable development in the middle and lower reaches of rivers in China and Southeast Asian countries.In the alpine area,the growing season of forage is short,the forage supply is sufficient in summer and autumn,and the forage supply is scarce in winter and spring.The problem of"loss of weight"has been formed for a long time.The influence of weeds on the establishment of artificial grassland should not be underestimated.As a kind of cultivation and management measure,protected sowing is of great significance to improve the coverage of perennial artificial grassland and solve the contradiction of low grass yield in the year of establishment and insufficient forage in winter and spring.In order to solve the problems of the shortage of forage grass in winter and spring and the influence of weeds on the establishment of artificial grassland in the alpine region.Elymus nutans,Festuca sinensis,Poa pratensis,Avena sativa and Lolium multiflorum were used as experimental materials,and unprotected sowing was used as control.In Maqin County,Qinghai Province,the effects of two grass species and four ratio of protective sowing on the initial grass yield and forage quality of three different utilization types of perennial mixed sown grassland were studied.The main results are as follows:（1）20%,30%,40%and 50%of the unicast amount of Lolium multiflorum(22.5 kg hm^-2)were used as protection species to build mowing mixed sowing grassland,its 2 years total hay yield 9389 kg·hm^-2,17284 kg·hm^-2,12263 kg·hm^-2and 14292 kg·hm^-2,which were increased by 2%,88%,33%and 55%compared with the control.The CPY of 30%L.multiflorum treatment was the highest,increased by 75%than control.Total hay yield under the treatments of 20%,30%,40%and 50%of the unicast amount of oat(225 kg hm^-2)is 25975 kg·hm^-2,25249 kg·hm^-2,27077 kg·hm^-2and 27306 kg·hm^-2,which were 182%,174%,194%and 196%higher than that of the control,and compared with the control,CPY of forage grass increased by 124%,143%,143%and 204%.Compared with the control,SS,NDF,ADF and RFV of protected sowing treatment did not change significantly.At the same time,the protected sowing significantly reduced the species and coverage of weeds,and inhibited the breeding of weeds.（2）When 20%,30%,40%and 50%of the unicast amount of L.multiflorum were used as protective grass species to build grazing perennial mixed grassland,the total hay yield increased by 47%,91%,85%and 86%compared with the control.Among them,CP of forage grass treated with 30%L.multiflorum increased by 1.79%,CPY increased by 95%compared with control.Compared with the control,the RFV of 50%forage grass in L.multiflorum was increased by 18.1%.Compared with the control,the total hay yield of the mixed-sown grassland constructed with oats in the same proportion as L.multiflorum as protective species increased by 194%,220%,265%and 273%,The CPY of grass planted with 20%oat was the highest,which increased by 190%compared with the control.In the second year,the soluble sugar content of perennial forages in mixed sown grassland was higher than that in the control and SS increased by 40.17%when the unicast amount of Lolium multiflorum was 50%.（3）Compared with the control,the 2 years total hay yield of the grazing type perennial mixed grassland with oat and L.multiflorum at different sowing ratios increased significantly,and showed a trend of increase with the increase of sowing ratio.The CP of grass with treatment of 20%,30%and 40%L.multiflorum increased by 11%,1%and 7%compared with the control.The CPY of oat protected sowing treatment was higher than that of L.multiflorum,but the effect of oat on perennial forage grass was greater than that of L.multiflorum.Compared with the control,the SS of 40%L.multiflorum treatment increased by 32%,the RFV of forage increased by 18.71%in the treatment of 30%of L.multiflorum unicast.The weed species of mixed sowing grassland decreased with the increase of the proportion of protected sowing.To sum up,with 2 years of agronomic traits of lawn grass and hay yield and quality analysis showed protected sowing with 30%L.multiflorum sowing ratio can effectively improve the grass yield and nutrition of mowing,dual purpose type and grazing perennial mixed grassland in alpine region,which is beneficial to the growth of perennial forage grass,and is an ideal protected sowing grass species and proportion for building artificial grassland.Therefore,it is advisable to use 30%L.multiflorum as protection species and sowing ratio in production practice.