交替灌溉对紫花苜蓿生物量分配与水分利用效率的影响

摘要

Alternate furrow irrigation has been widely applied to crop production in order to optimize the harves-ting of seeds and fruits.A field experiment was conducted to determine the effects of alternate furrow irrigation on alfalfa above-ground yield and its components,root biomass,root to shoot ratio and water use efficiency. The experiment aimed to establish whether alternate furrow irrigation can apply to alfalfa whose harvest target is vegetative mass.The results showed that alternate furrow irrigation significantly improved the water use ef-ficiency of alfalfa.Moreover,there was no significant effect on above-ground biomass because branches per plant increased while leaf numbers per plant decreased.Alternate furrow irrigation increased root biomass at 0-20 cm and 0-60 cm soil levels,but decreased root biomass at 20-60 cm.Alternate furrow irrigation also increased root to shoot ratio,therefore improving alfalfa’s drought resistance under water stress.These results prove that alternate furrow irrigation not only improves water use efficiency but also maintains the yields of al-falfa.It does so by improving plant drought resistance by encouraging root system development and increasing the number of branches per plant.The results thus indicate that alternate furrow irrigation can be applied to the management of alfalfa production.%交替灌溉是一种节水灌溉技术，广泛用于籽实作物和园艺作物的生产灌溉管理。本研究采用田间试验，分析了交替灌溉对紫花苜蓿地上生物量及其构成要素、根系生物量、地下地上生物量比和水分利用效率的影响，以期为紫花苜蓿生产中应用交替灌溉技术提供科学依据。结果表明，交替灌溉显著提高了紫花苜蓿水分利用效率，但没有显著影响紫花苜蓿的地上生物量；交替灌溉虽然增加了紫花苜蓿单株分枝数，但减少了单株叶片数；交替灌溉增加了0～20 cm 土层的根系生物量，降低了20～60 cm 土层根系的生物量，整体上增加了0～60 cm 土层根系的总生物量；交替灌溉增加了紫花苜蓿的地下地上生物量比，提高了紫花苜蓿植株适应干旱的能力。上述结果说明，交替灌溉能够提高紫花苜蓿水分利用效率而不减产，一方面通过增加紫花苜蓿根系发育能力而提高其耐旱性，另一方面增加了单株分枝数，因此交替灌溉能够适用于收获营养体的紫花苜蓿生产的灌溉管理。