不同水肥条件下分根区交替灌溉对玉米生理特性和水分利用的影响

为探讨分根区交替灌溉(AI)条件下作物生理响应和水分利用情况,在不同水肥条件下,以常规灌溉为对照,研究了分根区交替灌溉(AI)对玉米总干物质量、水分利用和生理指标的影响以及这些指标在恢复正常灌水后的恢复补偿能力,以期为玉米实施分根区交替灌溉提供科学依据。盆栽试验包括2种氮磷(NP)肥水平,2种灌溉方式和不同亏水水平,即拔节前期至中期(18d)进行正常灌水(70%—80%θf,θf是田间持水量)、轻度亏水(60%—70%θf)和中度亏水(50%—60%θf),拔节前期至中期处理后拔节中期至抽雄期(18d)进行正常灌水(70%—80%θf)和轻度亏水(60%—70%θf)。结果表明:与常规灌溉相比,拔节前期至抽雄期AI不显著影响玉米叶片叶绿素、类胡萝卜素、可溶性糖和脯氨酸含量,总干物质量和水分利用效率;与正常灌水相比,拔节前期至抽雄期轻度亏水也不显著影响上述指标;拔节前期至中期中度亏水降低玉米叶绿素含量和总干物质量,提高可溶性糖和脯氨酸含量,但是该处理在拔节中期至抽雄期恢复正常灌水后这些指标均恢复到一直正常灌水的水平。此外,施肥水平对各项指标的影响也不显著。因此,轻度亏水、低肥和拔节前期至抽雄期分根区交替灌溉结合可以节约灌水量和施肥量。

Effects of alternate partial root-zone irrigation on physiological characteristics and water use of maize under different water and fertilizer conditions

To investigate the physiological characteristics and water use of maize under alternate partial root-zone irrigation (AI), taking conventional irrigation as the control, the effects of AI on total dry mass, water use and physiological indices of maize plants were investigated under different water and fertilizer conditions and how these responses were recovered to the control levels when full irrigation was resumed, so as to provide scientific basis for the implementation of alternate partial root-zone irrigation for maize plants. Pot experiment was carried out at two nitrogen (N) and phosphorus (P) levels, two irrigation methods and different water deficit levels, i.e. normal irrigation (70%-80% θ_f, θ_f is field capacity), mild water deficit (60%-70% θ_f) and medium water deficit (50%-60% θ_f) for 18d at the early to middle jointing stage, and mild water deficit (60%-70% θ_f) and normal irrigation (70%-80% θ_f) for 18d at the middle jointing to tasseling stages after the early to middle jointing stage. Results indicate that compared to conventional irrigation, AI at the early jointing to tasseling stages did not significantly affect leaf chlorophyll, caroteniod, soluble sugar and proline contents, total dry mass and water use efficiency. Compared to normal irrigation level, mild water deficit at the early jointing to tasseling stages did not affect these indices significantly, either. Medium water deficit at the early to middle jointing stage decreased leaf chlorophyll content and total dry mass and increased leaf soluble sugar and proline contents, but resuming medium water deficit to normal irrigation at the middle jointing to tasseling stages could recover these indices to the control level. In addition, the indices were not affected by fertilization level. Thus the combination of mild water deficit, low NP and AI at the early jointing to tasseling stages can save water amount and fertilizer rate.