西藏高寒区禾-豆混播对牧草营养品质及土壤养分的影响

The effects of grass-legume mixing farming on forage nutritional quality and soil nutrient in alpine zone of Tibet

采用随机区组试验设计,以燕麦(Avena sativa)、箭筈豌豆(Vicia sativa)、饲用豌豆(Pisum arvense)为材料,于2019年在拉萨墨竹工卡具开展单播、禾-豆混播种植方式下牧草产量和品质的比较。通过分析种植后土壤养分的变化,在确保牧草生产性能的同时,探讨禾-豆混播的土壤改良作用。结果表明:(1)燕麦+箭筈豌豆、燕麦+饲用豌豆混播比例为70%∶30%和50%∶50%时,干草产量最高,较单播燕麦分别提高11.8%和28.0%,较单播箭筈豌豆、饲用豌豆分别提高24.5%和17.4%。(2)单播箭筈豌豆、饲用豌豆的粗蛋白(CP)含量最高,分别达19.29%和15.74%,混播处理中CP含量随着燕麦播种量的增加呈现降低的趋势,最高降幅分别达54.48%和57.12%;而中、酸性纤维则呈相反趋势。(3)单播燕麦土壤养分降低,有机质、全氮、碱解氮、有效磷和速效钾分别降低1.10 g·kg^(-1)、0.03 g·kg^(-1)、22.93 mg·kg^(-1)、3.27 mg·kg^(-1)和4.38 mg·kg^(-1)。而增加豆科植物的播种量可有效提高土壤肥力,增加速效养分供给,土壤有机质、全氮、碱解氮和有效磷最高可提升4.5%、9.1%、3.6%和6.1%。综上,进行一年生禾-豆混播具有实现牧草增产和农田保育的双重效应。

The forage yield,soil nutrients,and variation of soil nutrition were compared by monocultures of Avena sativa,Vicia sativa,Pisum arvense,and combination of A.sativa+V.sativa and A.sativa+P.arvense mixed patterns to explore the effects of soil amelioration while ensuring the performance of forage production in Maizhokunggar Sibu pasture of Tibet in 2019.The results showed that:(1)The hay yield of mixed sowing ratio of A.sativa∶V.sativa at 70%∶30%,and A.sativa∶P.arvense at 50%∶50%were the highest,which increased by 11.8%and 28.0%compared to monocultures of A.sativa,and increased by 24.5%and 17.4%compared to monocultures of A.sativa and P.arvense,respectively.(2)The crude protein(CP)of monocultures of V.sativa and P.arvense were 19.29%and 15.74%,respectively.The CP content of mixed sowing treatments showed a decreasing trend with increasing A.sativa sowing ratio,and the highest decreasing amplitude was 54.48%and 57.12%,respectively;while the neutral detergent fiber(NDF)and acid detergent fiber(ADF)showed the opposite trend.(3)The content of soil organic matter,total nitrogen(N),alkali-decomposed N,available phosphate(P),and available potassium(K)of monocultures of A.sativa were reduced by 1.10,0.03 g·kg^(-1),and 22.93,3.27,4.38 mg·kg^(-1),respectively,compared with that in the monocultures of A.sativa.Increasing sowing rate of legume effectively improved the soil nutrients.The content of soil organic matter,total N,alkali-decomposed N,and available P were increased by 4.5%,9.1%,3.6%,and 6.1%,respectively,which improved the supply of available nutrients such as alkali-decomposed N and available P.In summary,grass-legume mixture is beneficial to the purpose of increasing forage production and conservation of cultivated land.