黄土丘陵区枣林土壤水分调控技术研究

Abstract

针对黄土丘陵半干旱区大面积人工林草地土壤干化严重问题，而有关专门进行土壤水分亏缺的恢复试验研究缺乏的问题。本研究在陕北12龄山地密植枣林对秸秆覆盖、保水剂、聚水沟、少量补灌、矮化密植、缩小树体修剪措施下的土壤水分进行了定位试验观测，并结合林地根系调查，研究了几种措施对枣林土壤水分的调控作用。结果表明：秸秆覆盖、保水剂、聚水沟措施可分别影响0~260 cm、0~160 cm、0~300 cm土层的土壤水分含量，聚水沟措施具有更强的土壤水分调控功能；稀植枣林由于根系深度超过矮化密植枣林根系，从而增加了林地土壤深层水分亏缺；小量补充灌水会促进树木生长，而对土壤水分的恢复没有明显作用；通过修剪控制树体规格降低叶面积指数可以较好地减小枣树蒸腾耗水量，有利于土壤水分的调控，是土壤水分调控的新途径；研究认为在黄土丘陵半干旱区，可以尝试在矮化密植枣林结合应用聚水沟技术以及根据当地降雨调控枣树产量的节水型修剪技术，达到恢复土壤水分为目的的调控土壤水分手段。该研究对半干旱区旱作林草地土壤水分调控及可持续发展具有十分重要的意义。 There are many researches on soil moisture deficit of artificial forest and grass in Semiarid Loess Hilly Area, but a few studies are focused on the recovery of soil moisture deficit in this region. In this study, 12 old mountain in Northern Shaanxi jujube forest planting of straw mulch and water retaining agent, a small amount of irrigation ditch, poly, dwarfing close planting, soil moisture reduced tree pruning measures under the experiment observation, combined with forest root investigation, study the controlling effect of several measures on soil moisture in jujube forest. Results showed that the soil water content depths under straw mulching, water-retaining agent and rainwater harvesting ditch treatments can reach 260 cm, 160 cm, and 300 cm, respectively, but the rainwater harvesting ditch has stronger effect on soil moisture regulation. Dwarf and dense planting jujube can shoal the rooting depths and reduce deep soil water deficit, while sparse planting jujube plantations have deeper root system. A little supplemental irrigation would promote jujube growth, but has little effect on soil moisture restoration. Transpiration water consumption of jujube can be effectively reduced by pruning trees to control specifications and lowering leaf area index, which is beneficial to soil water regulation. Combined applied water-saved pruning and rainwater harvesting ditch technique, dwarfed dense Jujube plantations would effectively regulate soil moisture in Semiarid Loess Hilly Areas. The study is significant to soil moisture ecological restoration as well as sustainable development of forestry.