哀牢山木果石栎林凋落物矿质元素含量的研究

研究表明：木果石栎林凋落物年产量每公顷5．5－7．1吨。凋落物中落叶占80％。每公顷凋落叶中含氮91．5kg，磷3．7kg，钙101kg，铝5．7kg，钾42．1kg，钠0．3kg，镁10．7kg，锰5．6kg和铁1．9kg。每年4．6月为凋落物降落的高峰期。凋落物消失参数是基于测定凋落物的现存量与年凋落物量之间的比率，其系数范围为0．73-0．94。分解率的测定是采用该群落中七种优势树种的叶子）木果石栎、景东石栎、腾冲栲、长尾青冈、滇木荷、大花八角、米饭树和箭竹）为材料，在塑料网袋中进行，结果不同种间分解率有差异，其年分解率为68％－96％。分解率与采集地无关。各种植物凋落物中灰分元素含量有较大差异。

THE MINERAL-ELEMENT CONTENT OF LITERFALL IN A LITHOCARPUS XYLOCARPUS FOREST IN THE AILAO MOUNTAINS

The accumulation and decomposition of litter were studied over two separate years in an undisturbed Lithocarpus xylocarpus forest at c.2400-2600 m. altitude southwestern highlands of China. Mean annual litter fall amounted to 5.5 t ha-7.10 t ha~(-1) 80% of which was leaves containing 91.5 kg ha~(-1) nitrogen,3.7 kg ha~(-1) phosphorus,101 kg ha~(-1) calcium,5.7 kg ha~(-1) alminum, 42.1 kg ha~(-1) potassium,0.3 kg ha~(-1) sodium,10.7 kg ha~(-1) magnesium,5.6 kg ha~(-1) manganese,and 1.9 kg ha~(-1) iron. Litter falls have seasonal peaks from April to June,and May to October during the heavy rains.From January to December in 1984,the total rainfall was 1510.5 mm,and from January to Nevember in 1985,the total rainfall was 1975.5 mm. The estimater of annual rate parameter for litter disappearance were based on the relationship between the standing crops of litter on the ground and the annual litter production,ranging from 0.73 to 0.94. The leaf decomposition of seven tree species(Lithocarpus xylocarpus, Lithocarpus chintungensis,Castanopsis wattii,Cyclobalanopsis stewar- diana var.longicaudata,Schima noronhae,Illicium macranthum,Vaccinium duclouxii.)and a widespread bamboo(Sinarundinaria nitida),was studied ever one year by enclosing the litter in plastic mesh.For freshily-fallen leaves decomposition varied from species to species(from 68-96% yr),but it was not affected by the sites of collection.The ash nutrient content of eight species were determined,and the contents varied from species to species.