施肥对沙打旺根系提水及土壤养分活性的影响

采用上下桶分根法,通过下桶施肥研究施肥对沙打旺根系提水作用能力及上桶土壤养分活性的影响.结果发现：沙打旺根系提水量随施肥量的增加而增加;在上桶不浇水的情况下,高肥处理组上桶伴生的浅根植物早熟禾在干旱胁迫时间较短时较对照组生长正常;根系提水量最大时,高肥和低肥处理的上桶土壤呼吸速率分别比对照增加14.9%和51.4%,有机质含量分别下降17.8%、19.6%,速效磷分别增加13.9%、33.2%,速效钾分别增加20.4%和22.8%.研究表明,施肥促进了沙打旺根系的生长发育,增加了下桶根系吸水和上桶释水量,有效地缓解了上桶土壤的旱情,显著提高了上桶土壤养分的活化程度和有效养分含量.

Root Hydraulic Lift and Nutrition Activity in Astraglus adsurgens with Fertilization

The effects of fertilization on root hydraulic lift and nutrition activity in Astragalus adsurgens was investigated through root dividing methods by supplying different quantity of fertilizer to down parts of roots. The results indicated that the water volume of hydraulic lift increased with the increase of fertilizer supplying. Poa pratensis planted in upper basin without irrigation grew better than control because of hydraulic lift of A. adsurgens in the treatment group with more fertilizer. Furthermore, soil respiration rate in upper basin increased to the highest value and the active N,P and K in the soil of upper basin was also up to the best. In conclusion, fertilization promoted the root growth of A. adsurgens; the water which absorbed by the roots in down basin was released by the roots in upper basin. Therefore,drought stress was alleviated effectively, the activity of soil microbe was enhanced, the decomposition of soil organic matter was accelerated, the release of efficient nutrition was facilitated.