冬季放牧和春季火烧对新麦草生长与种子产量的影响

研究前一年冬季放牧和春季火烧对新麦草(Psathyrostachys juncea (Fisch.) Nevski)植株生长与种子增产效应,旨在提出新麦草种子高产的田间管理技术。结果表明:前一年冬季放牧和春季火烧处理均可明显促进新麦草种子田的生育进程,返青分别较对照提前23 d和19 d,以冬季放牧更为显著;两种处理可提高地上生物量、单位面积的平均分蘖数和分蘖株的大小,而且收获期基部功能叶的叶面积有所增加,均以冬季放牧最高,表明冬季放牧能够促进新麦草生殖生长,抑制营养生长;两种处理均可提高单位面积的生殖枝数,从而显著提高单位面积的潜在种子产量、表现种子产量和实际种子产量,均以冬季放牧最高,实际种子产量可达2303.9 kg/hm²,较春季火烧(1384.8 kg/hm²)和对照(928.4 kg/hm²)增产66%和148%;冬季放牧既可提高新麦草种子产量,又可充分利用种子田的饲草贮存,可作为重要的种子增产手段加以推广利用。

The Effects of Winter Grazing and Spring Burning on Plant Growth and Seed Yield in Russian Wildrye

Field managements after seed harvesting have significant effects on seed yield in next year in gramineous grasses.In order to provide a proper postharvest management techniques to increase seed yield,the effects of winter grazing and spring burning on plant growth and seed yield in Russian wildrye were investigated.The results show that both of winter grazing and spring burning could accelerate plant phonology stages,the dates of regrowth in spring were advanced of 23 days and 19 days by the treatments of winter grazing and spring burning,respectively,the effect of winter grazing on plant phonology stages was more significant.In addition to plant phonology stages,both winter grazing and spring burning improved above-ground biomass,average tiller number per unit area,tiller size,and the leaf area of the functional leaf at the base part of plants,the effects of winter grazing on all these four traits were more significant.Compared with the control,winter grazing could significantly promote reproductive growth and inhibit vegetative growth.Both of winter grazing and spring burning increased potential seed yield,apparent seed yield,and actual seed yield,due to the increased floret tiller number per unit area,especially,the highest seed yield reached at 2303.9 kg/hm2 under winter grazing treatment which was 66% and 148% higher than spring burning(1384.8 kg/hm2) and control treatments(928.4 kg/hm2).It was concluded that grazing in preceding winter will benefit not only on seed yield,but also forage supply,thus it was considered as a promising practical method for extended application in field.