玉米×墨西哥大刍草杂种饲草产量及其构成性状对密度和氮肥的响应

摘要

研究了不同密度和施氮量对玉米（Zea mays）×墨西哥大刍草（Z.mexicana）饲草产量及其构成性状的影响,结果表明,密度和施氮量对玉米×墨西哥大刍草杂种的饲草产量和产量性状影响显著。随着密度和施氮量的增加,饲草产量发生变化。饲草产量与绿叶片数、叶长、叶面积呈负相关,与密度、施氮量、主茎粗、分蘖数、叶宽、单株鲜质量呈正相关,与草长呈显著正相关（P〈0.05）;单株鲜质量与密度、草长、主茎粗、分蘖数、叶宽、叶面积相关显著。密度、单株鲜质量、草长对饲草产量直接作用分别在0.05、0.05、0.1水平差异显著,是影响饲草产量的重要因素。种植密度40 000株.hm-2、施氮量450kg.hm-2时,鲜草产量达到最高,为59 444.74kg.hm-2;干草产量达到最高时（12 374.39kg.hm-2）的种植密度和施氮量分别为40 000株.hm-2、600kg.hm-2。说明,玉米×墨西哥大刍草杂种种植密度在40 000株.hm-2的基础上施氮450kg.hm-2左右是饲草高产、优质的合理组合。%The effects of planting density and nitrogen application on the forage yield,yield component traits of Zea mays×Z.mexicana hybrid were studied using a split plot experiment with two factors.The results showed that there were significant responses of yield and yield component traits of Z.mays×Z.mexicana hybrid to planting density and nitrogen application,and the forage yield had changed with planting density and nitrogen application enrichment.The forage yield was negatively associated with green leaves,leaf length and leaf area,positively associated with density,nitrogen application,main stem perimeter,tillers,leaf broad and single plant fresh yield and very significantly positively associated with grass length.The single plant fresh yield was highly significantly associated with planting density,grass length,main stem perimeter,tillers and leaf broad and leaf area.Meanwhile,the direct actions of planting density(P0.05),single plant fresh yield(P0.05),grass length(P0.05) on forage fresh yield were significant at levels of 0.05,0.01,0.1,respectively.These results suggested that the planting density,single plant fresh yield and grass length were important characters for improving forage yield.The fresh forage yield of Z.mays×Z.mexicana reached the highest at 59 444.74 kg·ha-1 with the planting density and nitrogen application of 40 000 plant·ha-1 and 450 kg·ha-1,respectively;meanwhile,the maximum dry forage yield reached the highest at 12 374.39 kg·ha-1 when the planting density and nitrogen application of 40 000 plant·ha-1 and 600 kg·ha-1,respectively.In conclusion,planting at 40 000 plants per hectare and applying 450 kg nitrogen per hectare were best management practices.