拔节期深松对夏玉米干物质生产及光合作用的影响

Effects of Subsoiling at Jointing Stage on Dry Matter Production and Photosynthesis of Summer Maize

以郑单958为试验材料,以拔节期深松和不深松为主因素、两种施氮模式为副因素,研究拔节期深松对夏玉米干物质生产及光合作用的影响。结果表明,拔节期深松与不深松相比,夏玉米株高、穗位高分别降低了17.3 cm、9.0 cm,茎粗减少了2.7 mm,展开叶片数少1片;延缓吐丝期前叶面积指数(LAI)的增加及吐丝期后LAI的下降;吐丝期穗位叶的气孔导度、胞间CO2浓度、蒸腾速率、净光合速率分别降低了38.0%、25.3%、42.5%、2.0%;开花期前生物量降低了1 519.5 kg/hm2,开花期后生物量下降了168.8 kg/hm2;穗部性状变差,穗粒数下降近100粒,经济系数下降7%,子粒产量减少1 662.0 kg/hm2,拔节期不宜进行深松作业。两种施氮模式对夏玉米生长发育的影响差异不显著,耕作方式和施氮模式交互作用不明显。

Zhendan955 was applied in the field experiment. Two factors were concerned, subsoiling and nitrogen regimes. Each factor had two levels, i.e. subsoiling and non-subsoiling at jointing stage. Dry matter production and photosynthesis of summer maize were analyzed under these condtions. The results showed that compared with non-subsoiling, subsoiling at jointing stage achieved the following characters： plant height and ear height decreased by 17.3 cm and 9.0 cm, stem diameter decreased by 2.7 mm, and one leaf less; the increase of LAI before silking was limited, while decrease of LAI after silking was slow; stomatal conductance, intercellular CO2 concentration, transpira- tion rate, net photosynthetic rate of ear leaves decreased 38%, 25.3%, 42.5% and 2.0%, respectively; dry matter pro- duction was clearly reduced with 1 519.5 kg/ha less before flowering, 168.8 kg/ha less after flowering; ear character- istics became bad, i.e. grain number was 100 less, the economic index decreased by 7 percentage, grain yield reduced 1 662.0 kg/ha. So, not suitable for subsoiling at jointing stage. No significant difference was observed between two ni- trogen regimes; no interaction of subsoiling and nitrogen regimes was observed.