黄土区人工林地水分供耗特点与林分生产力研究

通过定位观测，分析了黄土区人工刺槐和油松林地供水与耗水关系、土壤水分动态及林木生长情况。结果表明人工刺槐和油松林4，5，6三个月林地土壤水分消耗大于供给，水分供耗矛盾突出，土壤贮水减少；雨季水分供给充足，土壤贮水增加；在干旱季节和年份，相同条件下，密度大的林分林地水分供耗矛盾突出，林地水分亏损严重；不同坡向，水分亏损量大小顺序为阳坡>半阳坡>阴坡；0～300cm土层土壤水分调查显示，阳坡、半阳坡密度较大的中林林分林地土壤含水量较低，出现干化现象；从水分生产力来看，由于林地水分供应不足，林木生长不同程度受到限制，林分生产力逐年降低。

Feature of Water Supply and Consumption and Productivity of Stand in Loess Region

Based on theories andmethods of hydrology,the main factors of water consumption and supply by stand survey andon-site observationater were obtained. Available water resource and regularity of watersupply and consumption in forest soil, the relationship between water supply and waterconsumption of black locust(Robinia pseudoscacia L.)and Chinese pine (Pinus tabulaeformisCarr.) forests were analyzed,which are used as the main tree species for establishment ofprotection forest in the loess area of the western Shanxi province. Water supply is lessthan water consumption in April, May and June, and more than water consumption in rainfallseason, in the high-density stand,the available water amount is relative inadequate,serious water deficit always occurs. Deficit amount of northward slope is higher than thatin southward slope. According to the determination of soil moisture in deeper soil layer,soil moisture is lower in medium-age forest with high-density in southward slope, so soilis becoming desiccation.Analysis results on correlation between water supply, consumptionand forest productivity show that opitimum water balance is the critical factor to improvewater potential productivity in forest, which plays important role in management ofprotection forest in similar types and areas.