北方寒区紫花苜蓿/无芒雀麦混播比例和刈割时期对青贮品质的影响

通过对紫花苜蓿和无芒雀麦不同混播比例混播,每年刈割两茬。以混播饲草的青贮营养指标和发酵指标为依据,对播种第3年的头茬草初花期、盛花期,以及二茬草的盛花期3个刈割时期的牧草进行青贮试验,并对青贮饲料品质和营养品质进行分析,运用灰色系统理论综合分析方法来探讨二者混播利用的最佳比例。结果表明:在以上3个时期刈割所制作的青贮中,混播组合E1(播种量为9 kg?hm-2紫花苜蓿+30 kg?hm-2无芒雀麦)青贮质量表现最好,尤其以二茬草盛花期青贮品质为优,此时发酵指标:pH为4.21、AN/TN为3.94%、乳酸为3.08%;营养指标:粗蛋白为16.78%、粗脂肪为3.95%,中性洗涤纤维为61.02%,酸性洗涤纤维为48.65%,可溶性糖为0.91%,该混播组合的干物质达6955.73 kg?hm-2。从产量因素考虑,在E1混播组合的生产条件下,以头茬草初花期+二茬草盛花期刈割制备的青贮干物质产量最高,为16337.13 kg?hm-2。

Effects of mixed sowing ratio and mowing period of Medicago sativa and Bromus inermis on silage quality in cold regions of north China

The aim of this study was to determine optimal conditions for the production of silage from Medicago sativa and Bromus inermis. The two crops were sown at different proportions and both were mowed each year. Silage tests were carried out in the early flowering period and full?bloom period of first stubble, and in the full?bloom period of second stubble in the third year. The results for silage tests conducted at the flowering period of second stubble have been published previously. The nutritional indicators and fermentation indicators of silage made from mixed forages were determined. The forage quality and nutrient quality of silage were determined, and the optimal mixed sowing ratio was determined using grey system theory. We compared the silages produced in the above three periods, and found that the mixed sowing combination E1 (sowing rate: 9 kg?ha-1 M. sativa+30 kg?ha-1 B. inermis) performed best, especially silage produced in the full?bloom period of second stubble (fermentation indicators: pH 4.21, ammonia nitrogen/total nitrogen 3.94%, lactic acid 3.08%; nutritional indicators: crude protein 16.78%, crude fat 3.95%, neutral detergent fiber 61.02%, acidic detergent fiber 48.65%, soluble sugars 0.91%). The dry matter of the mixed forage combination was 6955.73 kg?ha-1. Considering the yield factors, under the production conditions of the E1 mixed forages, the highest yield of silage made in the early flowering period of first stubble+the full?bloom period of second stubble was 16337.13 kg?ha-1.