播期对浑善达克沙地青贮玉米产量及生物量分配的影响

为研究播期对浑善达克沙地青贮玉米产量和生物量分配的影响，确定当地青贮玉米最佳的播期，分别在5月27日、6月4日、6月11日和6月18日4个时间播种，测定了不同品种青贮玉米的株高、叶面积及地上生物量。8月27日青贮收获结果显示：随播期推迟，青贮玉米株高、叶面积和地上生物量降低；5月27日和6月4日播种的青贮玉米各指标均显著高于6月11日和6月18日播种的青贮玉米（P〈0．05）。说明将当前生产实践中播种时间由6月中旬提前至5月底和6月初可显著提高青贮玉米产量。生物量分配研究表明，随播期推迟收获时茎生物量所占比例下降，叶生物量所占比例升高。由于玉米茎、叶的饲用性和牲畜利用效率不同，可针对不同饲喂需求选择播种时间，以提高青贮玉米的利用率。

Effect of sowing date on yield and phytomass allocation of silage maize in Hunshandak Sandy Land

To investigate the effect of sowing date on growth and yield of silage maize and to identify optimal sowing date, an experiment was carried out in Hunshandak Sand Land. Two cultivars of maize were sown on May 27, June 4, June 11 and June 18 respectively and their height, leaf area, aboveground phytomass, and phytomass allocation were investigated. The harvest results on 27 August show that the height, leaf area, and aboveground phytomass of the two cultivars decrease with delayed sowing date. Significant differences exist in the above variables for sowing dates between May 27, June 4 and June 11, June 18. Early sowing (from end of May to early June) increases yield of maize for silage over sowing in mid June as commonly practiced by the local people. Phytomass allocation analysis shows that, with delayed sowing date, percent of stem phytomass to total phytomass drops, while the ratio of leaf phytomass to total phytomass increases. As nutritional contents of leaf and stem are different, sowing date can be adjusted by alternation with livestock to realize the full use of silage maize.