不同刈割组合方式对皇竹草生长和生产特点的影响

Effects of different cutting height and frequency combinations on growth and production performance of hybrid giant napie

通过由刈割高度(留茬高度为5,10,15,20cm)和刈割频率(1次性和每隔60,40和30d刈割)组成的双因子试验,来研究不同刈割频率和刈割高度对地处温带的河南黄河滩区皇竹草的生长特点和生产性能的影响,以便解决该草在黄河滩区种植中存在的利用期短、产量低、品质差、易倒伏的难题。研究证明,刈割对皇竹草的生长和生产有显著的影响,1年多次刈割会降低茎叶比(S/L ratio)和叶面积指数(LAI),适度的刈割有利于提高鲜干比(F/D ratio)、单株分蘖数和生长速度,过频过低刈割(留茬高度为5cm,每隔30d刈割)有利有弊,有利的方面是能显著地提高鲜干比和单株分蘖数,能显著降低倒伏率;不利的方面是会显著降低皇竹草刈割后的再生速度,不利于饲草的生长和生产。试验证明,在中原地区种植皇竹草适宜每隔60d刈割1次,一年刈割2次,留茬15~20cm为宜,全年产草量为31.58~32.41tDM/hm^2,均显著地高于其他刈割组合,和一次性刈割相比,提高14.26%~17.34%(P<0.05),另外,适度刈割有利于减轻皇竹草的倒伏,减少收获中营养和能量的损失和浪费。总之,在河南黄河滩区种植皇竹草是非常必要,也是可行的,在科学种植,合理灌溉和及时施肥的基础上,保持合理刈割高度和适当的刈割次数是优化和协调生长和生产各指标的重要措施,减少不必要的产量和营养损失,有利于高产和稳产。

This experiment was designed to explore the effects of cutting regime on growth characters and pro duction performance of hybrid giant napie （Pennisetum sinense） planted on Yellow River flood plain, and consisted of a factorial combination of four cutting heights （cutting at 5,10,15 and 20 cm） and 4 cutting frequencies（cutting interval 30, 40, 60 and 120 d）, to address some difficult problems with this species, including short utilization period, low yield, poor forage quality, and a high incidence of lodging with this cropplanted in Yellow River flood plain under continental climate. The cutting regime had a significant effect on the growth and production of hybrid giant napie. Multiple cutting within a growing season decreased stem to leaf ratio （S/ L ratio） and leaf area index （LAI）, while optimal cutting （cutting at 15--20 cm height and 60 d intervals） raised fresh biomass to dry matter ratio （F/D ratio）, tiller density, and growth rate, compared to other treat- ments. More frequent and severe defoliation （cutting at 5 cm height and 30 d intervals） raised F/D ratio and number of single plant tillerings, noticeably decreased incidence of lodging, but decreased re-growth rate which was unfavourable to sustainable and efficient production of forage. The more favourable cutting regimes in- creased forage yield by 14.3%-17.3% compared to that （cutting only at 120 d cutting interval） and the annual forage yield reached 32 t DM/ha. Furthermore, optimal cutting decreased lodging, reducing losses of energy and nutrients at harvest. In conclusion, optimal cutting height and frequency, together with appropriate irrigation and fertilizer regimes were important to achievement of production potential, eliminating unnecessary losses in yield and forage quality.