灌水量对烤烟产量和水分利用效率的影响

Impacts of irrigation water amount on flue-cured tobacco yield and water use efficiency

灌水时期不当或灌水量过大会降低烟叶的产量,同时造成水分的浪费,探究烟草适宜的灌水量至关重要.在蒸渗仪中开展试验,研究了不同灌水量对土壤水分、烤烟的水分利用效率和产量的影响.结果表明：烤烟K326各处理不同土层含水率变化规律比较一致,（0,10]cm土层含水率受气温、日照等气候因素较大;（10,20]cm土壤含水率变化较剧烈;（20,60]cm土壤含水率在整个生育期变化比较平缓,尤其在成熟后期各处理均出现不同程度的回升趋势,结合烤烟成熟期生理活动减弱、需水量减少,说明成熟期采取较小的灌水量比较适宜.成熟期烤烟的干物质产量在一定范围内随灌水量的增大而增加,如果继续加大灌水量将出现＂报酬递减＂现象.结合烟叶产量、烟株长势、耗水量和水分利用效率的结果,表明2 700-3 000 m^3/hm^2可以作为烤烟K326适宜的灌水量.在烤烟生产中,应均衡协调产量、水分利用效率与耗水量之间的关系,在高产前提下,适当减少灌水量,可达到既高产又节水的协调统一.

Improper irrigation period or excessive irrigation can reduce tobacco yield and cause water waste,so it is very important to explore a suitable irrigation water amount for flue-cured tobacco.In this paper,a series of experiment are carried out in a fieldBy means of Lysimeter to study the effects of irrigation water amount on yield and water use efficiency of flue-cured tobacco.The experimental results show that the soil moisture is more greatly influencedBy climatic factors,such as temperature,sunshine and so on.The soil moisture changes dramatically in（10,20]cm thick soil layer,while in（20,60]cm thick soil layer,it keeps a little variation during the whole growth period.Note that in the late maturity period the soil moisture is slightly increased in（20,60]cm layer because of reduced water demandBy the weakened physiological activity of tobacco plants,suggesting a less irrigation water shouldBe applied in that period.Dry mass yield of tobacco rises with increasing irrigation water a-mount in a certain range at the maturity stage.However,if the irrigation water amount is beyond a certain high level,the yield can be lowed,i.e.the ＂ diminishing returns＂ phenomenon occurs.Considering dry leaf yield,plant growing,water consumption and water use efficiency as a whole,the suitable irrigation water amount for flue-cured tobacco K326 shouldBe 2 700-3 000 m^3/ hm^2.The relationships among yield,water consumption and water use efficiency shouldBe well balanced and coordinated in flue-cured tobacco cultivation.Under the premise of high yield,irrigation water amount shouldBe reduced properly to achieve a compromise between high yield and water saving.