灌水与覆膜对春玉米生长及水分利用效率的影响

在移动式遮雨棚内采用子母桶栽土培法,研究了充分灌水和调亏灌水2种灌水模式以及拔节期揭膜、抽雄期揭膜和全生育期覆膜3种覆膜时长对春玉米生长、产量和水分利用效率的影响。结果表明,覆膜可促进春玉米早期生长,而对后期生长不利。抽雄期是春玉米需水关键期,阶段蒸散模数达41.4%~47.2%。受前期亏水锻炼,调亏灌水复水后产生补偿效应,可有效协调植株根冠比并延缓衰老。与充分灌水相比,调亏灌水处理的总蒸散量减少4.3%~7.1%,水分利用效率提高1.9%~6.7%。抽雄期揭膜处理前期(覆膜时)增温保墒,后期(揭膜后)降温透气,与拔节期揭膜处理和全生育期覆膜处理相比,其相对产量和水分利用效率分别提高19.0%~23.3%和23.2%~26.0%。综合考虑产量、水分利用和环境因素,调亏灌水+抽雄期揭膜具有较好的节水、增产和环保效应,是适宜的春玉米灌水覆膜模式。

Effects of Irrigation and Plastic Film Mulching on Growth and Water Use Efficiency of Spring Maize

In the movable rainproof shelter,spring maize was cultivated in pots containing soil to study the effects of two irrigation schedules (full irrigation and regulated deficit irrigation)and three plastic film mulching times (mulching till jointing stage,mulching till tasseling stage and mulching all stages)on growth,yield and water use efficiency.The results showed that plastic film mulching was only beneficial to the growth of spring maize at early stage.Water was strongly demanded at tasseling stage of which evapotrans-piration percentage was 41.4%~47.2%.Regulated deficit irrigation treatments suffered from drought at early stage and compensa-tive effects were appeared after re-watering,which could effectively adj ust shoot root ratio and delay aging.Compared with full irri-gation treatments,regulated deficit irrigation treatments could decrease total evapotranspiration by 4.3%~7.1% and increase water use efficiency by 1.9%~6.7%.Mulching till tasseling stage could improve temperature,keep moisture in early period and decrease temperature,permeate air in later period.Compared with mulching till jointing stage and mulching all stages,mulching till tasseling stage could increase relative yield by 19.0%~23.3% and increase water use efficiency by 23.2%~26.0%.Taking yield,water use and environment into consideration,the treatment of regulated deficit irrigation and mulching till tasseling stage is yield increasing, water saving and environmental friendly.