León Juan Diego, González María Isabel, Gallardo Juan Fernando
Universidad Nacional de Colombia, Sede Medellín, Facultad de Ciencias Agropecuarias, Medellín, Colombia, Calle 59A 63-20, 14-330.
Rev Biol Trop. 2011 Dec;59(4):1883-94.
Plant litter production and decomposition are two important processes in forest ecosystems, since they provide the main organic matter input to soil and regulate nutrient cycling. With the aim to study these processes, litterfall, standing litter and nutrient return were studied for three years in an oak forest (Quercus humboldtii), pine (Pinus patula) and cypress (Cupressus lusitanica) plantations, located in highlands of the Central Cordillera of Colombia. Evaluation methods included: fine litter collection at fortnightly intervals using litter traps; the litter layer samples at the end of each sampling year and chemical analyses of both litterfall and standing litter. Fine litter fall observed was similar in oak forest (7.5 Mg ha/y) and in pine (7.8 Mg ha/y), but very low in cypress (3.5 Mg ha/y). Litter standing was 1.76, 1.73 and 1.3 Mg ha/y in oak, pine and cypress, respectively. The mean residence time of the standing litter was of 3.3 years for cypress, 2.1 years for pine and 1.8 years for oak forests. In contrast, the total amount of retained elements (N, P, S, Ca, Mg, K, Cu, Fe, Mn and Zn) in the standing litter was higher in pine (115 kg/ha), followed by oak (78 kg/ha) and cypress (24 kg/ha). Oak forests showed the lowest mean residence time of nutrients and the highest nutrients return to the soil as a consequence of a faster decomposition. Thus, a higher nutrient supply to soils from oaks than from tree plantations, seems to be an ecological advantage for recovering and maintaining the main ecosystem functioning features, which needs to be taken into account in restoration programs in this highly degraded Andean mountains.
植物凋落物的产生和分解是森林生态系统中的两个重要过程，因为它们为土壤提供了主要的有机物质输入，并调节养分循环。为了研究这些过程，在哥伦比亚中央山脉高地的一片栎林（洪堡栎）、松林（展叶松）和柏树林（葡萄牙柏木）中，对凋落物、现存凋落物和养分归还进行了为期三年的研究。评估方法包括：每隔两周使用凋落物收集器收集细凋落物；在每个采样年结束时采集凋落物层样本，并对凋落物和现存凋落物进行化学分析。观察到的栎林细凋落物量（7.5 Mg/公顷/年）和松林（7.8 Mg/公顷/年）相似，但柏树林（3.5 Mg/公顷/年）非常低。栎林、松林和柏树林的现存凋落物量分别为1.76、1.73和1.3 Mg/公顷/年。柏树林现存凋落物的平均停留时间为3.3年，松林为2.1年，栎林为1.8年。相比之下，现存凋落物中保留元素（氮、磷、硫、钙、镁、钾、铜、铁、锰和锌）的总量在松林中最高（115 kg/公顷），其次是栎林（78 kg/公顷）和柏树林（24 kg/公顷）。由于分解速度较快，栎林的养分平均停留时间最短，向土壤归还的养分最多。因此，栎林比人工林向土壤提供更高的养分供应，这似乎是恢复和维持主要生态系统功能特征的一个生态优势，在这片高度退化的安第斯山脉的恢复计划中需要考虑到这一点。
