施肥对落叶松人工林植物养分及生理特性的影响

以东北林业大学帽儿山实验林场的14年生落叶松人工幼龄林为研究对象，对白浆化的暗棕壤林地进行了施肥试验。采用完全随机排列的方法，在林分内设置了9个施肥处理和1个无肥对照。在生长旺盛期测定了叶片和根系的全N和全P质量分数以及光合速率、呼吸速率、叶绿素质量分数等指标。结果表明，单施520kg/hm^2尿素，在提高全N、全P质量分数的同时，还能促进根系对磷素的吸收和利用，增加光合速率和叶绿素质量分数；单施314kg／hm^2磷酸二铵，能加快根系对养分的转移速度，提高光合系数(光合速率／呼吸速率)，且是这些施肥处理中效果最好的施肥水平，这说明此林龄的落叶松林容易缺磷，应适量多施磷肥；处理436kg／hm^2尿素 236kg／hm^2磷酸二铵 133kg／hm^2氯化钾，由于K肥的混入，加快了根系对N、P的转移，使叶片中的质量分数增加，有利于光合作用的进行。因此，合理的施肥措施，不仅能提高落叶松人工林叶片与根系的养分质量分数，还能提高叶片的光合能力。对于此幼龄林，少N多P或N、P、K混合施肥效果最佳。

Influence of fertilization on plant nutrition and physiological characteristics in larch plantations

The test of fertilizer application for 14 year-old and 34 year-old larch plantations grown in lessivage dark brown soil were performed at Maoershan Mt. Experiment Forest Farm, Heilongjiang, China. Nine fertilizer application rates and a check were designed in forest land with the method of complete random processing. The total N and P, and photosynthetic rate, respiration rate, chlorophyll content, etc., were determined. The results showed that the urea application rate of 520 kg/hm2 increased total N and P, and also increased photosynthetic coefficient and chlorophyll content, and was an optimal application rate in all treatments. Those above indicated that phosphorous deficient in the larch plantation at the forest age could easily occur and adequate amount of fertilizers were needed. The application of potassium chloride increased the transportation of N and P in toots, and N and P content of leaves due to K fertilizer, which was of benefit to photosynthesis. Therefore reasonable application of fertilizer not only increased nutrients content in roots and leaves of larch plantation but also promoted photosynthetic ability of leaves. The treatment of a small amount of N and sufficient P, or mixed application of N, P, K gave rise to the best results for the young growth.