分期播种对陇东地区玉米产量的影响及适宜播期分析

为了应对气候变化，探讨气候变化对玉米播种期和产量的影响，达到趋利避害，提高气候资源利用率的目的，采用分期播种方法，对陇东地区玉米最适播种期进行研究。结果表明，玉米不同播期各发育期生长速度变化主要表现在苗期，播种较早的发育期生长速度慢，发育期间隔天数长；播种较迟的发育期生长速度快，发育期间隔天数短；不同播期各发育期干物质增长量的差异主要表现在生殖生长期，干物质增长量以第三和第二（对照）播期最高，而营养生长期各发育期干物质增长量差异较小；不同播期不同层次的土壤贮水量对产量的影响不同，无论是浅层（0~50 cm）还是深层（0~100 cm）土壤贮水量在出苗-拔节期对产量的贡献呈正效应，在抽雄-成熟期和播种期对产量的贡献呈负效应，且以浅层（0~50 cm）土壤贮水量对产量的影响较大；同时分析表明，以第三播期（4月22日）为最适宜播期，该生长期内光、温、水匹配好，干物质增长量最高，产量也最高。说明近年来气候变化使陇东地区玉米适宜播种期推迟，由之前的4月中旬推迟至4月下旬。

Analysis about the Effect of Stage Sowing on Maize Yield and Optimum Sowing Time in Longdong Region

In order to respond the climate change, and investigate the effect of Maize planting in different sowing time as a result of climate change, the test method of sowing were used in different time, research the optimum sowing maize in Eastern Gansu Province. The analysis about the experiment data of Maize sowing by stages show us： different sowing time’s growth speed change of maize mainly displayed in seedling stage, it grew more slowly which was seeded earlier, and time interval between two developmental phases was longer. It grew faster which was seeded later, and time interval between two developmental phases was shorter. Dry matters’increment of every developmental phase in different sowing time weren’t same, this difference mainly displayed in reproductive stage, increment of dry matters were the highest in the second and the third sowing stage, and in vegetative growth period the difference of dry matters’increment was inconspicuous. Soil water storage’s effect to yield was not the same in different sowing time and at different level of soil, no matter superficial layer or deep layer, soil water storage present positive effect from seeding stage to elongation stage,and present negative effect from teaseling stage to maturation stage, and especially had a major influence to yield at superficial layer. Meanwhile, result for analysis showed that the third sowing stage was the most optimum sowing stage, in growth period of this stage, light, temperature and water were matched well, dry matters had a good increment and yield. According to these conclusions, climatic change made the optimum sowing time of maize in Longdong region pulled off.