半干旱区柠条生长与土壤水分消耗过程研究

Growth of Caragana korshinskii and Depletion Process of Soil Water in Semi-Arid Region

在黄土高原半干旱区采用工程整地与生物措施相结合的方法 ,进行柠条灌木林建设与土壤水分消耗及调控恢复研究。结果表明 :在半干旱区柠条生长前 6年为幼龄期 ,6～ 14年为中龄期 ,14年后进入老龄期。幼龄期 0～ 80 0cm土壤中未形成干层 ,中龄期土壤干层厚度为 2 4 0～ 2 6 0cm ,老龄期干层为 70 0cm。水平阶整地丰水年土壤水分盈余 4 4 82mm ,对照亏缺 5 1 5～ 79 6mm ;平水年亏缺 5 3 91mm ,对照亏缺 10 3 6 4mm ;干旱年亏缺 10 2 87mm ,对照亏缺 15 3 32mm。不同降水年份土壤水分的补偿深度为 80～ 180cm ,对照为 2 1～ 4 5cm。根据柠条主根、侧根和毛根的根量分布比例得出 ,土壤水分要恢复正常 ,丰水年需要 13年 ,平水年需要 16年以上 ,干旱年约需 2 0年以上 ,而对照无论是丰水年、平水年还是干旱年均需 2

Combining with engineering and biological measures, the construction of Caragana korshinskii vegetation and excessive depletion and resumption of soil water were studied. The results showed that the whole growing stages could be divided into three phases—young-age period for the first six years, middle-age period from the seventh year to the fourteenth year and old-age period after fourteen years. In young-age period, dry layer of 0～800 cm soils did not formed, while in middle-age and old-age period, dry layer reached 240～260 cm and 700 cm,respectively. By level-step measures, soil water had a surplus of 44.82 mm in abundant precipitation year, deficiency of 53.91 mm in equal precipitation year and 102.87 mm in dry year, and its compensated depth of soil water in different precipitation year was 80～180 cm, while that of CK was deficiency of 51.5～79.6 mm, 103.64 mm and 153.32 mm respectively in different kinds of years and the compensated depth was 21～45 cm. According to the distributed proportion of the main root, the lateral roots and hair roots, it took 13 years for soil water of C. korshinskii vegetation by measures to resume natural situation in abundant precipitation year and over 16 years in equal precipitation year and over 20 years in dry year, while it took over 20 years for that of CK in any kinds of years.