耕作和保墒措施对冬小麦生育时期光合特征及水分利用的影响

为探明不同耕作保墒措施下冬小麦生育期间光合生理特征及其增产机理,采用田间试验,以常规耕作为对照,采用深松、秸秆覆盖、免耕、施用有机肥及保水剂等措施,研究了不同耕作和保墒措施对冬小麦生育期间光合作用、产量及水分利用效率的影响。结果表明:冬小麦光合速率和叶片水分利用效率均以孕穗期最高,而灌浆期最低。蒸腾速率和气孔导度均以扬花期最高。对不同处理而言,在各生育时期均以深松处理的光合速率和叶片水分利用效率最高,其次为秸秆覆盖处理。在拔节期、孕穗期和扬花期以有机肥处理的蒸腾速率最高,而灌浆期以秸秆覆盖的蒸腾速率较高,在全生育期对照的蒸腾速率均较低。气孔导度与蒸腾速率表现规律基本一致。不同耕作、保墒措施均提高了小麦的穗数、穗粒数及千粒重,以及小麦籽粒产量和水分生产效率,降低了小麦总耗水量;各处理中以深松处理的效果最佳,其产量和水分生产效率分别较对照提高19.6%和38.3%。相关分析表明:各时期的小麦光合速率及叶片水分利用效率均与小麦产量和水分生产效率呈正相关,且随生育期的推进,其相关性增强,特别在扬花期,光合速率对于小麦产量和水分生产效率的影响更显著。

Impact of tillage and soil moisture conservation measures on photosynthetic characteristics and water use of winter wheat

Tillage and soil moisture conservation measures have been critical in crop growth, water use and yield output. These measures have improved soil structure and increased soil organic matter content, soil infiltration, and soil temperature. Moreover, tillage and soil moisture conservation measures have increased photosynthetic characteristics. However, the degree of influence of photosynthetic physiological characteristics on crop yield and water productivity efficiency at different growth stages of winter wheat under different tillage and soil moisture conservation measures has been seldom reported. To therefore ascertain the photosynthetic/ physiological characteristics and mechanisms of yield increase under different tillage and soil moisture conservation measures, a field experiment was conducted to determine photosynthesis, yield and water use efficiency of winter wheat at different growth stages under the treatments of deep tillage, no-tillage, straw mulching, organic fertilization and water-retaining agent application. The results suggested that photosynthetic rate and leaf water use efficiency of winter wheat were highest at booting stage and lowest at grain-filling stage. Transpiration rate and stomatal conductance were highest at flowering stage. At all growth stages, photosynthetic rate and leaf water use efficiency were highest under deep tillage treatment, followed by straw mulch treatment. At jointing, booting and flowering stages, transpiration rate was highest under organic fertilization treatment. Then at grain filling stage, transpiration rate was higher under straw mulching and no-tillage treatments than in the other treatments. Transpiration rate under control treatment was lower during all the growth stages of winter wheat compared with that under tillage and soil moisture conservation measures. The trend of change in stomatal conductance and transpiration rate was consistent. Ear length, grain number per panicle, 1000-grain weight, yield and water productivity efficiency of winter wheat increased and total water consumption reduced under different tillage and soil moisture conservation measures. This was especially obvious under deep tillage. Wheat yield and water productivity efficiency were highest under deep tillage, respectively increasing by 19.6% and 38.3% compared with the control. Correlation analysis showed that photosynthetic rate and leaf water use efficiency were positively correlated with yield and water productivity efficiency. The correlations strengthened with advancing growth process, especially so at the flowering stage. At this stage, the effect of photosynthetic rate on wheat yield and water productivity efficiency was more significant than that of leaf water use efficiency.