贵阳市烟田土壤水分动态变化特征分析与研究

Analysis and Research of Soil Moisture Dynamic Characteristics in Guiyang City

[目的]为了掌握贵阳市烟田主要土壤水分变化动态，为烟田灌溉提供理论依据。[方法]分别对自然条件下不同李节、不同土层深度和坡度的自然降雨土壤水分动态进行研究。[结果]贵阳烟区在烤烟旺长期和成熟前期阶段性的土壤含水量是亏缺的，将限制烟叶产质量提高；成熟后期0～40cm土层土壤含水量最高，伸根期变幅最小，旺长期各土层的土壤含水量最低；受烤烟根系吸水综合作用的影响，层深15cm的土壤受地表蒸发的影响强烈，而层深30cm的土层正是烤烟根系密集区域，受根系的吸水影响较大；坡度可加大地表径流的作用，减少雨水的就地入渗量，降低烟地的蓄水量、保水量。[结论]自然雨养烟田土壤含水量呈浅“V”型，控水烟田土壤含水量呈倒“V”型，说明烟田抗旱能力随坡度增加而减低，在干旱季节旺长期和成熟期适量补水有利于烤烟产量的形成和品质的提升。

[ Objective] The research aimed to grasp moisture dynamics in the main tobacco field soil, and provide a theoretical basis for the to- bacco field irrigation. [ Method] Under natural conditions in different seasons, different soil depth and slope ,natural rainfall and soil moisture dy- namic were studied. [Result] Guiyang soil moisture was deficient in vigorous growing period and the mature stage, which would limit the tobacco leaf production and quality improvement. Soil moisture was the highest in the late stage of maturation late in 0 - 40 cm, that in root extending stage was the smallest, and soil moisture content in the period of vigorous growth was the lowest. Affecting by the comprehensive effect of water uptake of flue cured tobacco root, soil in the layer 15 cm was influenced strongly by surface evaporation, and 30 cm deep soil layer was the tobac- co root dense regions, which was affected strongly by the absorption of root. Slope could increase the surface runoff, reduce rainfall infiltration, and reduce smoke water storage and water holding capacity. [ Conclusion ]The natural rained tobacco field soil water content showed shallow ＂V＂ type, and control water content showed inverted ＂V＂ type. The drought resistance of tobacco field decreased with the increase of the slope. During the dry season, water in growing and mature period of flue-cured tobacco was favorable for the formation and the enhancement of the quality.