以8个玉米生产主推品种(4个专用型青贮品种、4个粮饲兼用型品种)为研究对象,动态监测试验玉米品种的籽粒和全株含水率,探究并明确了不同类型青贮玉米品种的籽粒与全株含水率动态变化特征。结果表明,(1)籽粒乳线位置处于1/4、2/4、3/4和4/4时,8个试验品种平均分别处于授粉后36.3 d、44.0 d、53.5 d和63.3 d,籽粒平均含水率分别为49.5%、38.8%、33.3%和30.8%,对应的全株平均含水率分别为76.9%、69.4%、58.9%和53.1%。(2)8个试验玉米品种全株含水率由70%降至60%平均需14.1 d,其中专用型品种平均需16.5 d、粮饲兼用型品种平均需11.1 d,专用型品种较粮饲兼用型品种所需时间长5.4 d。(3)籽粒乳线位置1/2-3/4以及全株含水率由70%降至60%期间,专用型品种中京科青贮516和雅玉26、粮饲兼用型品种中郑单958和京科968的籽粒及全株含水率降低速率均分别低于同类型其他品种。由此可见,试验青贮玉米品种青贮适收期全株含水率70%-60%对应籽粒乳线位置1/2-3/4；专用型青贮品种的适收期较粮饲兼用型品种长5 d左右；青贮适收期内籽粒生理降水速率和全株含水率降低速率均较低,是京科青贮516和雅玉26、郑单958和京科968青贮适收期相对较长的主要原因。
Eight maize varieties (four certified as special silage maize and four certified as cereal grain maize) were used in order to study and clarify the dynamic changes of the grain and whole plant water content for different types of silage maize varieties. The results showed that (1) At the milk line position of 1/4, 2/4, 3/4 and 4/4, the tested eight varieties were averaged 36.3, 44.0, 53.5 and 63.3 d after pollination, respectively. The averaged grain water content was 49.5%, 38.8%, 33.3%, 30.8%, and the corresponding averaged whole plant water content was 76.9%, 69.4%, 58.9% and 53.1%, respectively. (2) The duration of the whole plant water content for the tested eight varieties decreased from 70% to 60% averaged 14.1 d, and the special silage maize varieties averaged 16.5 d which 5.4 d longer than that of the cereal silage maize varieties (averaged 11.1 d). (3) The decreasing rates of grain and whole plant water content of special silage varieties Jingkeqingzhu516 and Yayu26, cereal silage varieties Zhengdan958 and Jingke968 were lower than those of other varieties of the same type during the grain milk line 1/2-3/4 and the whole plant water content from 70% to 60%. In conclusion, the period of the whole plant water content from 70% to 60% of the tested silage maize varieties during the suitable harvest period was corresponding to 1/2-3/4 of the grain milk line position; the suitable harvest period of the special silage varieties was about 5 d longer than that of the cereal silage varieties; the relative lower values of the grain physiological precipitation rate and the decreasing rate of the whole plant water content during the suitable silage harvest period were the main reasons for the relative longer suitable harvest periods of Jingkeqingzhu516 and Yayu26, Zhengdan958 and Jingke968.