晋西黄土区主要造林树种耗水特性分析

Analysis of Water Consumption of Main Afforestation Species in Western Shanxi of Loess Plateau

依据水量平衡原理,采用盆栽试验分别测算了晋西黄土区主要造林树种油松、刺槐、苹果在其生长季（4～10月）成熟单株树木的耗水量,并根据林地土壤水分动态及土壤水分特征曲线标定的各树种无效水界值,分析了各树种土壤水分供耗特点及其有效性。研究结果表明：①2002贫水年生长季降水量430.7 mm,试验树种同期耗水量约为430～470 mm树木供耗失衡,2003丰水年降水量870.2 mm,耗水量约为450～510 mm但降雨分配不均,5,10月树木供耗也略有失衡;②不同树种年内土壤含水量变化趋势相近,而同月耗水量差异较大,同一树种不同月耗水量差异也较大,丰水年各试验地土壤水分状况要好于贫水年;③油松、刺槐、苹果1和苹果2无效水界值为：8.0%,8.4%,9.4%和9.9%,油松较其它树种利用水分能力最强。贫水年单株树木土壤含水量在一段时间内低于对应树种的无效水界值,影响树木正常生长。单株树木依靠冬季和次年春季降水补充,生长季初期都能恢复到速效水水平。

In order to provide the scientific basis and practical instruction for the vegetation reconstruction and recovery in Loess Plateau, this paper measured and calculated water consumption of potted mature Pinus tabulaeformis,Robinia pseudoacacia, Malus pumila 1 and Malus pumila 2 separately during the growing season （from Apr. to Nov. ）, which were the main afforestation species in western Shanxi of Loess Plateau, based on the theory of prevention of water transport in horizontal direction. Besides, according to the data of soil water dynamic and the range of available moisture of potted mature trees,it analyzed the relationship between water supply and consumption and the soil moisture availability and deficit state. Several conclusions are listed as follows： ① In the deficit water year （2002）, during the growing season the precipitation was 430.7 mm and the water consumption of potted trees was from 430 mm to 470 mm. More water consumption and less available water supply occurred,showing a serious water deficiency. In the abundant water year （2003）, during the growing season the precipitation was 870.2 mm and the water consumption of potted trees was from 450 mm to 510 mm. Due to uneven distribution of rainfall, the water budget lost balance a bit in May and Nov. ② The curves of soil water content of different species have similar change trends in annual but different in same month. Those of same species in different test plots have different change trends in same month either.③Non-available soil water content of Pinus tabulaeformis,Robinia pseudoacacia, Malus pumila 1 and Malus pumila 2 is less than 8.0% ,8.4% ,9.4% and 10.9% respectively,which indicates that Pinus tabulaeformis use water more efficiently than others. In the deficit water year （2002）, for several months, soil water content of potted trees is lower than its nonavailable soil water content, which could influence trees healthy growing. After supplements of precipitation of winter in the year and spring in the next year, soil water contents are higher than the lower limit of soll readily available moisture content.