氮肥用量、刈割高度对饲用苎麻产量、营养品质及败蔸的影响

探讨了氮肥用量和刈割高度对“湘苎3号”(Xiangzhu-3)和“多倍体1号”(Tri-1)饲用产量、营养品质及败蔸的影响,为“湘苎3号”和“多倍体1号”作为饲用作物的开发利用提供理论支持。采用两因素随机区组设计,刈割高度设3个水平,分别是40 cm(D₁)、70 cm(D₂)和100 cm(D₃);氮肥设置3个水平,分别是每次施氮0 kg/hm²(N₁)、92 kg/hm²(N₂)和138 kg/hm²(N₃)。通过测定各处理饲用苎麻鲜物质产量、干物质产量、营养物质含量及败蔸率,对不同氮肥用量和刈割高度处理的苎麻饲用价值进行综合评价。结果表明,氮肥用量和刈割高度对湘苎3号和多倍体1号鲜物质产量、干物质产量、粗蛋白、粗脂肪、粗灰分、粗纤维和磷含量影响显著,其中刈割高度是苎麻鲜物质产量、干物质产量和粗纤维有关参数的主要决定因子,湘苎3号粗蛋白含量主要由刈割高度决定,而多倍体1号粗蛋白含量主要由氮肥用量决定。其交互作用对湘苎3号和多倍体1号粗脂肪和粗纤维含量影响显著。在相同刈割高度下,湘苎3号和多倍体1号鲜物质产量、干物质产量、粗蛋白和粗脂肪含量均以N₂处理最高,粗纤维含量随着氮肥用量的增加而降低。在相同氮肥用量下,湘苎3号和多倍体1号粗蛋白、钙和磷含量随刈割高度的增加而降低,生物产量和粗纤维含量随刈割高度的增加而增加。与此同时,多次刈割会引起湘苎3号和多倍体1号不同程度的败蔸。在本试验条件下,湘苎3号和多倍体1号最适合的刈割高度是70~100 cm,氮肥用量是92 kg/hm²。

Effect of nitrogen fertilization rate and cutting height on yields,nutritive values and root-rot incidence in forage ramie

Ramie (Boehmeria nivea )is rich in nutrients,and is a protein source for animal feed.The objective of this study was to investigate the effects of nitrogen fertilization rate and cutting height on forage yields,nu-tritive values and root-rot (a common disease in ramie)of Xiangzhu-3 and Tri-1 varieties,and thus provide ad-visory support for use of Xiangzhu-3 and Tri-1 ramie varieties as a forage crop.A field trial was conducted with a two-factor randomized block design (3×3),including three cutting height levels (40 cm,D1 ;70 cm,D2 ;100cm,D3 )and three levels of nitrogen fertilizer (0 kg/ha,N1 ;92 kg/ha,N2 ;138 kg/ha,N3 ).Dry matter yield (DM),nutrient content and root-rot incidence were measured to elucidate the effect of different nitrogen fertili-zation and cutting height treatments on the feeding value of Xiangzhu-3 and Tri-1 ramie varieties.Nitrogen fer-tilization and cutting height had significant effects on biomass,dry matter (DM)yield,crude protein (CP), crude fat (EE),crude ash (Ash),crude fiber (CF)and phosphorus (P)contents of Xiangzhu-3 and Tri-1. Cutting height was the dominant factor affecting DM and CF.For CP content,Xiangzhu-3 was most influenced by cutting height,while Tri-1 responded to by nitrogen fertilization.Both EF and CF data displayed significant interaction between cutting height and nitrogen fertilization.Additionally,both ramie varieties had greatest DM,CP,and EE under the N2 treatment within each cutting height treatment,while the CF content was de-creased with increased nitrogen fertilization levels.In each nitrogen fertilization treatment,the CP,calcium (Ca)and P contents of Xiangzhu-3 and Tri-1 were decreased and the biomass and CF were increased with in-creased cutting heights.Increasing cutting frequency increased the root-rot incidence of Xiangzhu-3 and Tri-1. In summary,this study indicated that the optimal clipping height and nitrogen fertilization treatments of Xiang-zhu-3 and Tri-1 ramie varieties were 70-100 cm and 92 kg/ha,respectively.