干旱条件下施肥与作物抗旱性的关系

Relationship between Fertilization and Drought Resistance of Crop under Drought Condition

施肥与作物抗旱性有着密切的关系,对土壤肥力和氮﹑磷﹑钾三大营养元素与作物抗旱性关系的研究证明:旱地施肥后,满足了作物对营养元素的需求,促进了作物生长,增强了生理活动,通过渗透、水分、气孔、光合调节等生理生化机制影响作物的代谢活性。水分胁迫条件下施肥使叶片水势增强,束缚水含量增高,根系生长增强,作物吸水增强,气孔导度降低,水分散失减少,对作物水分生理及形态建设影响显著,提高了作物的抗旱性。不同营养元素与抗旱性的关系是不同的:如氮的抗旱作用随土壤干旱程度的加剧而降低,随着氮用量的增加甚至出现负效应;受到水分胁迫时,增施磷肥对植物的抗旱性一直表现为良好的正效应,而且在严重干旱时效果更加明显;因此,随干旱程度的加剧应适当增加磷肥的施用量。营养元素间配合施用有利于提高作物的抗旱能力。

Drought is a global problem,and it also is the uppermost natural disaster affecting crop growth and yield.Fertilization has a close relationship with the drought resistance of crops.The researches on the relationship between the drought resistance of crops and soil fertility,nitrogen,phosphorus and potassium nutrition showed that： after fertilization in dry land,the crop growth was promoted,the nutrient demand of crop was met;and at the same time,the physiological activity of crop was enhanced,and the metabolism was regulated by osmotic adjustment,water regulation,stomatal regulation,photosynthesis regulation and other biological and biochemical mechanisms.The leaf water potential and bound water content of crops were increased by fertilization under water stress,the root growth and root water uptake were promoted,the stomatal conductance and the transpiration were decreased,and the water physiological properties and the morphology of crops were obviously improved,so the drought resistance of crops was increased.The relationships between the drought resistance of crops and different nutrients were different.The effect of nitrogen on the drought resistance of crops was decreased with the increase of soil drought,and nitrogen even had negative effect along with the increase of its application rate.Increasing phosphorus application rate had good positive effect on the drought resistance of crops under water stress,and the effect was more significant under severe drought condition.Therefore,it was necessary to properly increase the application rate of phosphorus fertilizer when soil drought increased.The balanced fertilization could increase the drought resistance of crops.