不同增氧滴灌方式对蔬菜生长生理指标的影响

为了研究不同增氧方式对盆栽小白菜生长生理指标的影响,以小白菜为供试作物,采用盆栽地下滴灌的方式,以普通地下滴灌作为对照(CK),设置循环曝气(MAI)、双氧水(H₂O₂)、纯氧扩散器曝气(OC)及射流振荡器曝气(FO)4个增氧灌溉处理.结果表明,增氧地下滴灌显著提高了土壤呼吸速率,处理MAI,OC和FO较对照处理分别增大了65.87%,66.79%和111.62%.增氧地下滴灌促进了小白菜的根系生长、光合作用、蒸腾速率和气孔导度,进而提高了小白菜的物质量积累和产量.与对照相比,处理MAI的地下部鲜质量增大了42.03%,地下部干质量增大了79.85%;处理MAI,H₂O₂,OC和FO的光合速率分别增大了868.62%,794.14%,778.67%和650.19%;处理MAI,H₂O₂和OC的气孔导度较CK增大了157.14%,128.57%和85.71%,蒸腾速率增大了55.61%,32.38%和19.58%;处理MAI和H₂O₂的产量分别增大了56.36%和38.72%.综上,增氧地下滴灌可增强小白菜根区的土壤呼吸作用,改善光合作用、蒸腾速率和气孔导度,提高了产量及水分利用效率.其中,循环曝气处理的改善效果最为显著.

Effects of oxygation techniques on growth and physiology of vegetable under subsurface drip irrigation

Perched water often leads to a decrease in soil aeration in subsurface drip irrigated crop roots,whereas aerated subsurface drip irrigation(ASDI)provides a source of oxygen in a root environment that suffers from temporal hypoxia and unlocks yield potentials of crops.With Chinese cabbage as test crop,five irrigation treatments were used including Mazzei air injector(MAI)cyclic aeration,15 mg/L of hydrogen peroxides(H 2O 2),fluidic oscillator(FO),oxygen concentrator(OC)and a control treatment(CK).The experiment was carried out during September 23,2015 to October 31,2015 at the Central Queensland University,Australia(23°22′0.345″S latitude,150°31′0.53″E Longitude),and subsurface drip irrigation was implemented to systematically monitor soil respiration,crop growth and physiological indexes to clarify the effect of different oxygation techniques on growth and development of potted Chinese cabbage.Compared with the control treatment,the soil respirations in treatments MAI,H 2O 2,OC and FO increase by 65.87%,42.07%,66.79%and 111.62%respectively compared with CK.ASDI improves the leaf chlorophyll content in treatments MAI,OC and FO.The photosynthetic rate,stomatal conductance and transpiration rate are enhanced by SADI.The photosynthetic rates in MAI,H 2O 2,OC and FO increase by 868.62%,794.14%,778.67%and 650.19%compared with CK.The stomatal conductance in MAI,H 2O 2 and OC increases by 157.14%,128.57%and 85.71%,the transpiration rates in MAI,H 2O 2 and OC increase by 55.61%,32.38%and 19.58%,and there is not statistically significant difference between other treatments.The yield is significantly increased,and the water utilization efficiency(WUE)is improved,too.The yield increases by 56.36%and 38.72%respectively in treatments MAI and H 2O 2,and the WUE in MAI and H 2O 2 increases by 48.96%and 36.46%compared with CK.The beneficial effects of ASDI are mediated through greater root activity,especially the root-shoot ratio increases by 49.61%in MAI.In conclusion,ASDI improves the hypoxic environment in crop roots,promotes the growth of Chinese cabbage,enhances the soil respiration and increases the yield as well as water utilization efficiency.Among four treatments,MAI is ranked in the first place.