Abstract:

Within China， Ningxia makes an important contribution to national animal husbandry and production for human benefit. Information on the regenerative capacity of forage species is essential to forage supply for the sustainable development of animal husbandry in the region. This study reports a pot experiment on five oat varieties denoted： ‘Challenger’ （TZZ）， ‘Tianyan No.1’ （TY）， ‘Molasses’ （MLS）， ‘Xiyun’ （XY）， and ‘Baiyan No.7’ （BY）， with stubble height treatments of 5， 10， and 15 cm， and a control treatment of cutting at ground level （CK）. The regenerative mechanisms and differences among the five varieties under the different stubble heights were analyzed at the heading stage. It was found that： 1） With increase in stubble height， the plant height， tiller number， leaf area， and stem and leaf biomass of the five oat varieties gradually increased， while the root biomass and root-shoot ratio gradually decreased. Under the 5 cm treatment， the stem and leaf biomass of TY and MLS was inhibited， while that of TZZ， XY， and BY showed equal-compensatory growth. Under the 10 cm treatments， the stem and leaf biomass of XY and MLS showed equal-compensatory growth， while that of TZZ， TY， and BY showed over-compensatory growth. Under the 15 cm treatments， the stem and leaf biomass of all five oat varieties showed over-compensatory growth. 2） The starch and soluble sugar contents in the leaves and roots of the five oat varieties increased with increase in stubble height. The soluble protein contents in the leaves and roots of TZZ， TY， and MLS increased with increase in stubble height， while those of XY and BY decreased. After cutting， the crude protein content of oats decreased， while the neutral detergent fiber （NDF） and acid detergent fiber （ADF） contents increased. The crude protein content significantly increased with increase in stubble height （P<0.05）， while the NDF and ADF contents decreased. The relative feeding value increased with increase in stubble height. 3） Principal component analysis results indicated that the variation range was MLS>TZZ>TY and BY>XY. The grey relational analysis showed that the weighted rankings of all varieties under the 15 cm treatments were higher than those under the 5 cm treatments. The rankings from high to low were MLS-15 cm>TZZ-15 cm>TY-15 cm>TY-10 cm>BY-15 cm>TZZ-10 cm>MLS-10 cm>XY-15 cm>BY-10 cm>TY-5 cm>BY-5 cm>XY-10 cm>XY-5 cm>MLS-5 cm>TZZ-5 cm.

Key words: oat, stubble height, regrowth, forage quality, compensatory growth