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泡桐林的营养元素含量较高。在各个器官中,叶中的氮和钙含量最高,分别为2.6%和1.5%,钾、镁和磷含量也比较丰富。树干中营养元素含量最低,氮、磷、钾含量比花、叶明显减少,而钙含量比较丰富。叶和枝条是泡桐的氮素贮存库,其中叶的贮氮量占泡桐林木总氮量的42—53%。根是磷和钾的贮存库,根中含磷量占总量的39—56%,含钾量占总量的36—50%。钙主要贮存在树干中,干中钙量占总钙量的40—56%。镁和锰的贮存库主要在叶和枝中。泡桐每年吸收的营养元素,主要输送到叶子中,叶子吸收量占吸收总量的58—74%,其中氮素吸收量最大,吸收的氮素70—85%输送到叶子中。树干吸收营养元素最少,只占总吸收量的10%.泡桐林一年吸收的大量元素421公斤,其中增加到新生组织中175公斤,通过枯落物归还给林地125公斤,降雨淋洗归还96公斤,茎流冲洗24公斤。泡桐林的总循环率为63.38%。其中镁和钾的循环率最高,分别为80.49%和75.56%;氮的循环率最低,为33.54%,其它元素在二者之间。由此看出,泡桐林地中的氮素有减少的趋向.
Paulownia forest nutrient content is higher. In all organs, leaf nitrogen and calcium content of the highest, respectively, 2.6% and 1.5%, potassium, magnesium and phosphorus content is also abundant. The content of nutrients in the trunk was the lowest, while the content of nitrogen, phosphorus and potassium in the trunk was significantly lower than that in the flowers and leaves, while the content of calcium was relatively abundant. Leaves and shoots are the nitrogen storage reservoirs of Paulownia, in which the amount of nitrogen stored in the leaves accounts for 42-53% of the total nitrogen in the trees. The root is a repository of phosphorus and potassium, with phosphorus in the roots accounting for 39-56% of the total and potassium in 36-50% of the total. Calcium is mainly stored in the trunk, dry calcium accounted for 40-56% of total calcium. Magnesium and manganese repositories are mainly found in leaves and branches. Paulownia annual absorption of nutrients, mainly transported to the leaves, leaf absorption accounted for 58-74% of the total absorption, of which the largest nitrogen uptake, absorption of 70-85% of nitrogen delivered to the leaves. Tree trunk to absorb nutrients at least, accounting for only 10% of the total absorption of Paulownia forest absorb large amounts of 421 kg of elements a year, of which 175 kg to new tissue, through the litter returned to 125 kg of woodland, rainfall leaching returned 96 Kg, stem flow rinse 24 kg. Paulownia forest total recycling rate of 63.38%. The highest recycle rates of magnesium and potassium were 80.49% and 75.56% respectively. The lowest nitrogen recycle rate was 33.54% and the other elements were in between. From this we can see that the nitrogen in paulownia woodland tends to decrease.