南疆干旱灌溉区青贮玉米农艺性状和发酵品质动态分析及评价

为研究荒漠灌溉地区青贮玉米农艺性状和发酵品质动态变化规律以及筛选第三师地区最佳青贮玉米栽培品种,选择4个青贮专用和11个粮饲兼用型玉米品种为试验材料,分别在灌浆期、1/4乳线期、1/2乳线期和3/4乳线期进行农艺性状测定并调制青贮饲料。发酵60 d进行青贮饲料发酵品质、营养成分和体外消化测定,以农艺性状、营养成分、发酵品质和消化特征为评价指标,利用相似优先比法对15个玉米品种进行综合评价。结果表明:随生育期推进各青贮玉米株高、穗位、鲜草产量、全株鲜重、茎秆鲜重、果穗鲜重、籽粒鲜重、干物质(DM)、粗蛋白(CP)、可溶性碳水化合物(WSC)、淀粉含量和代谢能(ME)不断递增,到3/4乳线期达到峰值;其中,3/4乳线期大丰30鲜草产量最高,金玉9号DM含量最高,新饲玉10号CP含量最高,先玉696 WSC含量最高,屯玉765淀粉含量最高,均与其他品种差异显著(P<0.05)。随生育期推进,中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量、氨态氮∶总氮(NH₃-N/TN)、有机物消化率(OMD)和产气速率不断递减,ADF、NDF、NH₃-N...

Agronomic traits and fermentation quality of maize silage harvested at different grain-development stages in irrigated drought areas of southern Xinjiang

To study the changes in agronomic traits and fermentation quality of maize silage harvested at different stages of grain development in desert irrigated areas and to screen for the best-performing maize silage cultivars in the Third Division area， four silage-specific and 11 grain-feeding maize varieties were evaluated， and agronomic traits determined. Silages were prepared at the grain-filling stage， and when the milk line reached the 3/4 milk stage， 1/2 milk stage and 1/4 milk stage， of grain development. Nutrient composition， fermentation quality and in vitro digestion were measured after 60 days of fermentation， and the agronomic traits， nutrient composition， fermentation quality and digestion characteristics were used as evaluation indexes for the multi-factor evaluation of the 15 maize varieties using the similarity priority ratio method. It was found that silage corn plant height， cob position， fresh dry herbage yield， whole plant fresh weight， stalk fresh weight， cob fresh weight， seed fresh weight， dry matter （DM）， crude protein （CP）， water soluble carbohydrates （WSC）， starch content and metabolizable energy increased incrementally as grain development progressed， and reached a peak at the 3/4 milk stage. Among the varieties， Dafeng 30 had the highest fresh herbage yield， Jinyu 9 had the highest DM content， Xinsiyu No. 10 had the highest CP content， Xianyu 696 had the highest WSC content， and Tunyu 765 had the highest starch content， with values significantly different from other varieties （P<0.05）. Conversely， the contents of neutral detergent fiber （NDF）， acid detergent fiber （ADF）， the ratio of ammonia nitrogen：total nitrogen （NH₃-N∶TN）， the organic matter digestibility （OMD） and the gas production rate decreased incrementally as the reproductive period progressed， and ADF， NDF and NH₃-N/TN were lowest at the 3/4 milk line stage. Among the varieties， ADF content was the lowest in Xinsiyu No.12， NDF content was the lowest in Xinsiyu No.10 and NH₃-N∶TN was the lowest in Xinsiyu No.11 at the 3/4 milk line stage， with their values significantly different from other varieties （P<0.05）. OMD and gas production rate peaked in the filling period， with Xianyu 696 having the highest OMD and Xinsiyu No. 10 having the highest gas production rate， with both significantly different from other varieties （P<0.05）. The pH of the silage of each maize variety initially decreased and then increased at different grain-development stages， while the lactic acid （LA） content initially increased and then decreased， and there was no significant pattern of change with fertilizer in acetic acid and propionic acid. The silage pH value was lowest when harvested at the 1/2 milk line stage， and the variety with lowest pH was Tunyu 765. Silage LA content was highest when harvested at 1/4 milk line stage， with Xinsiyu No.12 significantly higher than from other varieties （P<0.05）. In summary， harvest of silage maize at the 3/4 milk line stage produced high yielding and high quality silage forage， and the multi-factor scores of Xinwo No.1， Tunyu 765 and Dafeng 30 were highest among the tested varieties. Therefore these three varieties are recommended for planting in the Third Division area of Xinjiang and in ecologically similar regions.