准噶尔盆地荒漠-绿洲过渡带梭梭单株水分生长函数

Water-growth function for single Haloxylon ammodendron tree in desert-oasis ecotone of the Junggar Basin

为了探究准噶尔盆地荒漠-绿洲过渡带梭梭的水分生长规律、确定梭梭的生长耗水下限,在野外对6种土壤水分环境下的梭梭耗水和枝条生长过程进行了为期2年的定点观测和研究。结果表明:1)6、7月份的降水量对梭梭的耗水量和枝条的生长状况有显著影响。梭梭在不同降水年份的6、7月份日均耗水量的变化幅度大于0.07mm/d,枝条生长速度的变化幅度大于0.03cm/d;而在5月份和8月份日均耗水量的变化幅度低于0.06mm/d,枝条生长速度的变化幅度低于0.02cm/d。2)在选取的5种数学模型中,Hossfeld模型拟合效果较好,模型结构稳定,可以反映出梭梭在水分胁迫条件下的生长规律。3)荒漠-绿洲过渡带的梭梭在非水分胁迫下生长时,其耗水量下限为97.65mm,而保证梭梭生存的最低耗水量为59.80±1.37mm。研究结果可为确定准噶尔盆地荒漠-绿洲过渡带梭梭林的生态需水量提供参考和理论依据。

For researching the relationship of the Haloxylon ammodendron growth and its water consumption in the desert-oasis transition zone of the Junggar Basin and to determine the lower limit of water consumption for H.ammodendron,the water consumption and branch growth process of the H.ammodendron had been observed and studied under six soil moisture conditions in field for two years.The results showed that:1)The water consumption intensity and growth of H.ammodendron were significantly impacted by the precipitation in June and July compared with that in May and August,in which,daily water consumption of H.ammodendron in June and July was greater than 0.07mm/d and the branch growth speed was greater than 0.03cm/d,but in May and August,they were only less than 0.06mm/d and less than 0.02cm/d,respectively.2)Among the five mathematical models selected,the Hossfeld model has good fitted effect and stable structure,which could perform the growth behaviour of H.ammodendron under a condition of water stress.3)The lower water consumption for H.ammodendron growing under the non-water stress condition was 97.65mm in the desert-oasis ecotone,while 59.80±1.37mm was the lowest water consumption and indispensable for H.ammodendron to survive.The results of this study can provide a reference and theoretical basis for determining the ecological water demand of H.ammodendron forest in the desert-oasis ecotone of the Junggar Basin.