播期和密度对玉米子粒机收主要性状的影响

以京农科728为试验材料,设置5个播期、5个密度处理,研究播期和密度对玉米子粒机收主要性状影响。结果表明,不同播期条件下,京农科728产量6 723.0~7 972.5 kg/hm~2,6月10日、6月15日、6月20日3个播期产量达7 500 kg/hm~2以上,子粒机收主要质量指标(子粒含水率、杂质率)达到国家玉米机收子粒标准。不同密度条件下,以75 000株/hm~2密度处理子粒产量最高,达到国家玉米机收子粒标准。京农科728在5个播期处理条件下均能正常成熟,生育期随播期推迟呈缩短趋势;随种植密度增加,其生育期呈延长趋势。株高和穗位高随播期推迟及种植密度增加呈升高趋势;倒伏率随播期推迟呈降低趋势,随种植密度增加呈升高趋势。播期和密度与玉米子粒机收性状密切相关,京农科728在北京夏播以6月10~20日为最佳播期,75 000株/hm~2为最佳密度,可实现子粒直接机械收获。

Effects of Sowing Date and Planting Density on Maize Grain Mechanical Harvesting Related Traits

In order to illustrate the effects of sowing date and planting density on maize grain mechanical harvesting related traits, a field experiment was conducted with five sowing dates and five planting densities by using Jingnongke728 at Tongzhou research station. The results showed that the yield of Jingnongke728 was 6 723.0- 7 972.5 kg/ha under different sowing date conditions, and exceeded 7 500 kg/ha during June 10-20th sowing treatments with the grain mechanical harvesting quality reaching the national standard; the yield under different planting densities was the highest under 75 000 plant/ha, which reaching the national maize grain mechanical harvesting standard. Jingnongke728 could mature normally under different sowing conditions, and the growth period shortened with the delay of sowing date, but delayed with the increase of planting density. The plant height and ear height of Jingnongke728 were increased with the delay of sowing date and the increasing of planting density; the lodging rate was decreased with the delay of sowing date, but increased with the increasing of planting density. Thus, sowing date and planting density were closely related with maize grain mechanical harvesting traits. Jingnongke728 can realize grain mechanical harvesting production with sowing during June 10-20th and planting with 75 000 plant/ha in Beijing summer-cultivated conditions.