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在东北地区设置大田试验,研究不同耕作方式下玉米全生育期耕层土壤温度、土壤含水量、叶片光合性能及叶绿素荧光参数的变化特征.结果表明:耕作方式对土壤水热性能的影响主要体现在播种-拔节阶段,2010—2011年平地播种中耕起垄(PL)和全生育期平作(PP)处理0～40 cm土层土壤体积含水量在出苗期、苗期和拔节期比传统垄作(LL)处理平均提高5.6%和5.2%、4.6%和7.3%及3.9%和4.8%,苗期5 cm土壤最低温度分别比LL处理高1.4和1.3℃.由于土壤水热条件的改善,拔节期PL和PP处理的叶片净光合速率(Pn)、蒸腾速率(Tr)等指标显著高于LL处理,而PSII潜在活性(Fv/Fo)和PSII最大光化学效率(Fv/Fm)无显著差异,表明气孔导度和气孔限制值等气孔因素是导致光合作用差异的主要原因;灌浆期叶片Pn和Tr则以LL和PL处理显著高于PP处理,这主要是由于PP处理在强降雨时期经历了涝渍灾害,光合作用受到抑制.可见PL处理通过改善土壤水热条件增强了玉米光合性能,进而提高了籽粒产量.
Field experiments were conducted in Northeast China to study the characteristics of soil temperature, soil water content, photosynthetic characteristics and chlorophyll fluorescence parameters under different tillage patterns in the whole growth period of maize.The results showed that the effects of tillage patterns on soil water and heat were mainly reflected In the sowing-jointing stage, the soil volumetric water content in 0-40 cm soil layer during sowing of PL (2010-2011) and flat cropping (PP) LL) increased by 5.6% and 5.2%, 4.6% and 7.3%, 3.9% and 4.8% on average, and the minimum temperature of 5 cm in seedling stage was 1.4 and 1.3 ℃ higher than that of LL treatment, respectively. Due to the improvement of soil hydrothermal conditions, The indexes of Pn and Tr of PL and PP treatments were significantly higher than those of LL treatments, while there was no significant difference between PSII latent activity (Fv / Fo) and PSII maximum photochemical efficiency (Fv / Fm) Stomatal conductance and stomatal limitation were the main reasons for the differences in photosynthesis. Pn and Tr in grain filling stage were significantly higher than those in PP and LL treatments, which was mainly due to waterlogging in PP treatment during heavy rainfall Disaster, photosynthesis suppressed Visible PL process by improving the conditions of soil water thermally enhanced photosynthetic performance of corn, grain yield further improved.