【作者】 韦艳葵；

【导师】 贾黎明；

【作者基本信息】 北京林业大学 ， 森林培育， 2003， 硕士

【摘要】 本文研究了北京沿河沙地地下滴灌条件下杨树人工林树木速生丰产机制，并对地下滴灌优化灌溉制度进行了初步的探索，结果表明：与常规灌溉相比，地下滴灌能大大增加树木的生长量、提高林地生产力。2000年(栽植第4年)，地下滴灌区树木平均胸径、树高和单株材积分别达到21.18cm、14.23m和0.1815m~3，比常规灌溉增加了54.5％、36.9％和247.6％；林地生产力达到22.78～25.81m~3/hm~2.yr，比常规灌溉增加了3.9～4.6倍。进一步的研究表明，地下滴灌区树木速生丰产的机制在于地下滴灌通过持续提高林地土壤含水量，大幅度增加林地树木吸收根量(＜2mm的细根增加了88.32％)，提高树木对N、K养分的吸收量和活化能力(叶、枝、粗根含N量提高107.77～199.86％，枝、细根、粗根含K量提高26.57～69.78％)，持续改善树木的水分条件(树木叶水势在一天中小于对照12％～42％，在一个地下滴灌周期清晨叶水势小于对照25％～38％)，持续提高树木的个体和群体光合速率(一天中叶净光合速率提高10.0～21.4％，一个滴灌周期提高9.0～9.9％)，并持续提高水分利用效率(提高幅度最高达到18.5％)。分灌溉4小时、8小时和12小时三个处理，通过对树木生长、土壤含水量、树木叶水势和光合因子等的研究综合表明沙地条件下杨树幼林地下滴灌灌溉4小时(灌水量为80～120升/株.次)为最佳灌水持续时间，开始灌溉的土壤临界含水量需在7～15％之间，据此确定灌溉周期。文章最后建议在干旱半干旱和季节性干旱地区营造速生丰产用材林时应结合当地经济条件推广地下滴灌技术，并建立相应的优化节水灌溉制度，使我国人工林生产力赶超世界先进水平。更多还原

【Abstract】 The fast-growing and high-yield mechanisms of poplar plantations on subsurface drip irrigation (SDI) on sandy soil in Beijing were studied and the optimized water-saving irrigation system of SDI was also primarily researched in this paper. The results show that: The growth of poplar trees and the plantations productivity were more increased on SDI than on normal irrigation (NI). In 2000 (3 years after planted), the average Di.3, H and volume per tree are 21.18cm, 14.23m and 0.1815 m3 on SDI and were 54.5%, 36.9% and 247.6% more than on NI. The plantations productivity on SDI reached 22.78-25.81m3/ hm2.yr and were 3.9-4.6 times as long as on NI. The further study shows that: The fast-growing and high-yield mechanisms of poplar plantations on SDI were that by the soil moisture content improved sustainably, the amount of absorbing roots on SDI could be increased greatly (fine-roots (<2mm) on SDI sites increased by 88.32%), the N and K absorbed content and activated ability of trees on SDI could be increased greatly (N content of leaves, branches and coarse roots increased by 107.77-199.86%, K content of branches, fine-roots and coarse roots increased by 26.57-69.78%), the water status of trees on SDI could be continually improved (water potential of trees leaves on SDI during a day 12%-42% lower and during an irrigation period 25%-38% lower than on NI), the photosynthetic speed of individual and colony on SDI could be continually improved (the photosynthetic speed of trees leaves on SDI during a day 10.0-21.4% higher and during an irrigation period 9.0-9.9% higher than on NI), the water use efficiency of trees on SDI could be continually improved (the tiptop of increased range reached 18.5%). Based on the three treatments of 4 hours, 8 hours and 12 hours irrigation durations of SDI, the studies of the trees growth, the soil moisture, the leaves water potential, the leaves photosynthetic speedand others showed synthetically that 4 hours of SDI (the irrigated water amount was 80-120 litre/per tree . per time) was the best irrigation duration of SDI in poplar young plantations on sandy soil, the critical soil moisture of irrigation start would be between 7% and 15%, the cycle of SDI would be confirmed by it. At last, extending the underground drip irrigation in developing the fast-growing and high-yield plantations in arid, sub-arid and season arid area according to the local economic condition is suggested. And it is also suggested that a corresponding optimized water-saving irrigation system of SDI must be established on the local condition and make the plantation yields reach the high level of the world.更多还原