施肥对日本落叶松不同根序细根养分浓度的影响

以辽宁东部山区16年生日本落叶松人工林为对象，探讨施肥对落叶松1～5级不同根序等级细根养分浓度的变化.结果表明：不同根序等级细根全碳浓度差异不显著，施肥对各级根序全碳浓度没有显著影响;在前5级根序中，1级根非结构性碳水化合物（TNC）浓度最低，N和P浓度最高;而5级根TNC浓度最高，N和P浓度最低.TNC浓度随着根序增加而升高，N和P浓度则相应下降.施肥仅对1级根组织中N和P浓度有显著影响;不同根序根组织中C/N/P具有明显差异，1级根平均C/N/P为423∶16∶1，5级根为726∶16∶1，随着根序增加，C在3种元素中的比例显著增加，而N的比例变化不大.施N肥并没有改变C的比例;但施P肥或施N+P肥均降低了前3级根（0～10 cm）或前2级根（10～20 cm）C和N在3种元素中的比例.

Effects of climate change on vegetations on Qinghai-Tibet Plateau: A review

With the 16 years old Larix kaempferi plantation in eastern mountain area of Liaoning Province, China as test object, this paper studied the effects of fertilization on the nutrient concentrations of five root orders’ fine roots. Under fertilization, less difference was observed in the total C concentration of the fine roots. Among the five orders’ fine roots, the first order’s had the lowest concentration of non-structural carbohydrate (TNC) and the highest ones of N and P, while the fifth order’s was in adverse. The TNC concentration increased with increasing root order, while the N and P concentrations decreased correspondingly. Fertilization only had significant effects on the N and P concentrations of the first order’s fine roots. The C/N/P ratio in different orders’ fine roots had significant differences, being 423∶〖KG-*2〗16∶〖KG-*2〗1 and 726∶〖KG-*2〗16∶〖KG-*2〗1 in the first and the fifth order’s fine roots, respectively. With the increase of root order, the proportion of C increased significantly, while that of N varied little. N fertilization didn’t change the proportion of C, while P or P+N fertilization decreased the proportions of C and N in the first three orders’ fine roots at 0〖KG-*2〗-〖KG-*7〗10 cm soil depth or in the first two orders’ fine roots at 10〖KG-*2〗-〖KG-*7〗20 cm soil depth.