夏季模拟放牧对青藏高原冬春草场牧草品质和土壤养分的影响

The Effect of Modulating Different Utilizing Intensity in Summer Season on Forage Quality and Soil Nutrients of Winter&Spring Pasture on Qinghai-Tibetan Plateau

为探索青藏高原地区草畜高效管理模式,本试验采用刈割模拟家畜采食的方式在夏季牧草生长季(8月初,称作青草期)利用冬春草场,并在牧草生长季末(10月初,称作枯黄期)采集牧草和土壤样品,研究不同利用强度对牧草再生、生物量、品质以及土壤养分的影响。试验结果表明:3种不同利用强度对牧草枯黄期地上生物量、牧草酸性洗涤纤维(Acid detergent fiber,ADF)和中性洗涤纤维(Neutral detergent fiber,NDF)没有产生显著影响;不同草地利用强度处理组枯黄期粗蛋白(Crude protein,CP)含量均显著低于青草期,而ADF和NDF的结果刚好相反(P<0.05);枯黄期重度利用草场牧草CP含量显著高于不利用组(P<0.05),中度利用强度0~10 cm土壤速效磷含量显著高于对照组(P<0.05)。本试验结果表明,青藏高原在牧草生长季利用冬春草场(留茬2~4 cm),家畜不仅能够摄取优质的青绿牧草,而且不会降低牧草生育期总生物量。

The objective of the present study is to explore high efficiency managing strategies of grazing system on Qinghai-Tibetan Plateau.In this study,grazing was simulated by mowing forage.The grass and soil samples were collected in grass growing season and the end of growing season(beginning of October)to evaluate the regrowth capacity,biomass and quality of forage,and the soil nutrients level.The results showed no significant effects of different utilizing intensity on forage above-ground biomass,neutral detergent fibre(NDF)or acid detergent fibre(ADF)contents.The forage crude protein(CP)was lower in withering period than growing period in all the three treatments(P<0.05).And the NDF and ADF contents were conversed.The forage CP content of high utilizing treatment was higher than control in withering period(P<0.05).The soil available phosphorus in 0~10 layer was higher in middle utilizing intensity than control in withering period(P<0.05).In conclusion,appropriate grazing utilization(2~4 cm stubble)of Winter and Spring pasture in forage growing period supply high quality forage for livestock without decreasing the total forage yield.