刈割期与晾晒天数对饲料油菜产量和粗蛋白含量及水分的影响

Effects of Harvest Date and Drying Days on the Yield,Crude Protein Content and Moisture of Forage Rapeseed

为了明确长三角地区饲料油菜适宜收获期与晾晒时间,2016-2018年连续2年开展田间试验,终花至角果期刈割5次并于田间晾晒,比较不同刈割期和晾晒天数下饲草产量、粗蛋白含量及水分变化差异。结果表明,与首次刈割(终花期)相比,终花后4到16d刈割饲草鲜重显著增加,饲草干重分别提高了31.93%、41.50%、49.14%和61.43%。随着刈割时间延迟,饲草粗蛋白含量呈下降趋势,末次刈割饲草含水量显著降低(P<0.05)。油菜终花后4d刈割,并于田间晾晒第4和5天时,其鲜草含水量由82.16%下降为71.45%和65.26%。不考虑刈割期,田间原位晾晒3d,平均鲜草含水量由81.00%下降至66.30%。晾晒期间土壤累积温度每增加10℃,鲜草含水量降低2.30%。由此,长三角地区稻茬油菜在终花后4d刈割,饲草鲜产和粗蛋白含量均能达到较优水平,刈割后田间原位晾晒4~5d,可满足青贮水分要求。

In order to determine the appropriate harvest date and drying days of forage rapeseed,a field study was conducted from 2016 to 2018 in the Yangtze River Delta region.Rapeseed plants were harvested at five different dates from final-flowering stage to podding-stage,and then drying in the field till the weight constant.The biomass yield,crude protein content and water content of forage rapeseed were compared among different harvest dates and drying days.The results showed that compared to the first harvest date(at final-flowering stage),the fresh weight were significant higher at 4 to 16d after final-flowering stage,and the dry weight at the last four harvest dates were improved by 31.93%,41.50%,49.14%and 61.43%,respectively.The concent of crude protein trended to decrease with the harvest time delayed,the water content was significantly lower at the last harvest date(P<0.05).Cutting 4d after final-flowering,the water content dropped from 82.16%to 71.45%and 65.26%after drying for four and five days in the field.The forage water content went down from 81.00%to 66.30%after drying for three days.In situ drying of the rapeseed plant in the field,the forage water content was decreased by 2.30%with the soil cumulative temperature increased by 10℃.Overall,in the Yangtze River Delta region,to obtain the ideal biological yield and crude protein content of forage rapeseed,it is optimum to harvest at four days after final flowering stage and then to be dried in situ for four and five days to meet the silage water requirement.