刈割和施氮对豆禾混播草地牧草生长特性及品质的影响  

Effects of mowing and N application on growth characteristics and quality of forage grasses in legume-grass mixtures

作　　者：王辛有 曹文侠[1] 师尚礼[1] 王小军 王世林 刘婉婷 白洁 李文 WANG Xinyou;CAO Wenxia;SHI Shangli;WANG Xiaojun;WANG Shilin;LIU Wanting;BAI Jie;LI Wen(College of Grassland Science,Gansu Agricultural University/Grassland Ecosystem Key Laboratory of Ministry of Education/Sino U.S.Research Centers for Sustainable Grassland and Livestock Management,Lanzhou 730070,China;Animal Science and Veterinary Medicine,Qinghai University,Xining 810000,China)

机构地区：[1]甘肃农业大学草业学院/草业生态系统教育部重点实验室/中-美草地畜牧业可持续发展研究中心,兰州730070 [2]青海大学畜牧兽医科学院,西宁810000

出　　处：《中国生态农业学报（中英文）》2022年第9期1439-1450,共12页Chinese Journal of Eco-Agriculture

基　　金：国家重点研发计划项目(2016YFC0400306);国家现代农业产业技术体系项目(CARS-34)资助。

摘　　要：为探究放牧与施肥对河西走廊豆科禾本科(简称“豆禾”)混播草地生产性能与群落结构稳定性的调控机制,并确定该草地所适用的最佳放牧利用与施肥管理模式,本研究以‘清水’紫花苜蓿(Medicago sativa‘Qingshui’)、无芒雀麦(Bromus inermis)和长穗偃麦草(Elytrigia elongate)建植的混播草地为试验对象,采用L_(16)(3^(1)×4^(2))混合位级正交试验设计,设20 cm(S_(1))、30 cm(S_(2))和40 cm(S_(3))3个刈前高度,2 cm(E_(1))、5 cm(E_(2))、8 cm(E_(3))和11 cm(E_(4))4个刈割强度,0 kg(N)∙hm^(−2)(N_(1))、75 kg(N)∙hm^(−2)(N_(3))、150 kg(N)∙hm^(−2)(N_(3))和225 kg(N)∙hm^(−2)(N_(4))4个施氮量,分析了不同处理下混播草地群落结构及生产性能。结果表明:1)刈前高度及施氮量对草地生产性能影响较大,S_(3)E_(2)N_(4)的生物量最大(17707.80 kg∙hm^(−2)),S_(1)E_(1)N_(4)的混合草粗蛋白含量最高(15.46%),S_(3)E_(1)N_(3)的混合草相对饲用价值最大(184.93)。2)降低刈割强度可增加利用次数,并使禾本科牧草在群落中的占比增大,其中S_(2)E_(3)N_(4)、S_(1)E_(3)N_(3)、S_(1)E_(4)N_(1)、S_(2)E_(4)N_(3)和S_(1)E_(1)N_(1)可使豆禾盖度比接近1∶1,S_(2)E_(3)N_(4)、S_(3)E_(3)N_(1)和S_(3)E_(4)N_(3)对草地分枝数的调控作用效果最好。3)与刈割收获干草(区内一年刈割3次)相比,模拟放牧降低了产草量,但提高了牧草营养价值,抑制了群落中紫花苜蓿比例的过快增长,能维持豆禾草种结构的稳定性。综上,S_(2)E_(3)N_(4)能使混播草地群落结构的稳定性最好,且具有良好的生产性能(草地生物量为15173.41 kg∙hm^(−2),粗蛋白含量为13.92%,相对饲用价值为156.93),是适宜此类混播草地放牧利用与施肥管理的参考指标,可在河西走廊等类似地区推广应用。Scientific and rational modes of grazing utilization and fertilization management are important agronomic measures to maintain the production performance and community structure stability of legume-grass mixtures.The study aimed to explore the regulation and control mechanisms of grazing and fertilization on the production performance and community structure stability of perennial legume-grass mixtures,and to preliminarily determine the optimal mode of grazing utilization and fertilization management for legume-grass mixtures.In the Hexi Corridor area,a 4-year-old mixed grassland with Medicago sativa‘Qingshui’,Bromus inermis,and Elytrigia elongata(at 1∶1∶1)were used as the study objects.The L_(16)(3^(1)×4^(2))mixed level orthogonal experimental design was used with three heights prior to mowing:20 cm(S_(1)),30 cm(S_(2)),and 40 cm(S_(3));four mowing intensities:2 cm(E_(1)),5 cm(E_(2)),8 cm(E_(3)),and 11 cm(E_(4));four nitrogen application rates:0 kg(N)∙hm^(−2)(N_(1)),75 kg(N)∙hm^(−2)(N_(2)),150 kg(N)∙hm^(−2)(N_(3)),and 225 kg(N)∙hm^(−2)(N_(4));and the impacts of artificial mowing to simulate grazing utilization combined with nitrogen application on the community structure and production performance of mixed grassland were monitored and analyzed.The study showed that the height prior to mowing and the amount of nitrogen added had a greater impact on the production performance of mixed grasslands.The total biomass of grassland under the S_(3)E_(2)N_(4) treatment was the highest(17707.80 kg∙hm^(−2)),the crude protein content of mixed forage under the S_(1)E_(1)N_(4) treatment was the highest(15.46%),and the relative feeding value of mixed forage under the S_(3)E_(1)N_(3)treatment was the highest(184.93).Additionally,reducing the mowing intensity could increase utilization times and the proportion of gramineous forages in the community.Among them,the coverage ratios of leguminous forages and Gramineae grasses under the treatments S_(2)E_(3)N4,S_(1)E_(3)N_(3),S_(1)E_(4)N_(1),S_(2)E_(4)N_(3)

关 键 词：豆禾混播草地 施氮量 刈前高度 刈割强度 群落结构 生物量 牧草品质 

分 类 号：S812[农业科学—草业科学]