As compared to natural forest ecosystems, soils under agroecosystems are more subjected to changes in physical and biochemical attributes. But, tree species that are retained and/or planted on these agroecosystems replenish soil fertility through the influence of leaves litterfall quantity and quality. Tree species-related differences in the quantity and seasonality of leaves litterfall and the associated amounts of annual returns of nutrient elements were assessed from four multipurpose tree/shrub species (Erythrina brucei Schweinf, Cordia africana Lam., Grevillea robusta R. Br. and Malus sylvestris Mill.) in homegarden agroforestry systems. Five replicates of two leaf litterfall traps per species were randomly positioned beneath the subcanopy area for 12 months, totaling 40 litterfall traps distributed among the four species. The results of this study suggested that total annual leaves litterfall varied significantly among species (ranging from 171.18 to 962 kg ha− 1), with the combined per tree mean monthly (28.13 kg tree− 1), per tree annual (331.10 kg tree− 1 year− 1) and per area basis total annual (9439.33 kg ha− 1) leaves litterfall production. A clear seasonal leaves litterfall pattern with varying peaks was observed for the multipurpose tree/shrub species in the present study, with a bimodal distribution pattern for E. brucei and C. africana and a unimodal distribution pattern for G. robusta and M. sylvestris. Similarly, both the concentrations and inputs of nutrients from the leaves᾽ litterfall showed considerable variations among species (p < 0.05). Among the investigated species, C. africana and E. brucei were found to be the best in terms of carbon (C) and nitrogen (N) return, G. robusta the best in terms of phosphorous (P) return, and C. africana as well best for potassium (K) return. The combined mean annual nutrient inputs recorded for all the species were 3125.32 kg C ha− 1 year− 1, 149.70 kg N ha− 1 year− 1, 54.86 kg K ha− 1 year− 1, and 3.56 kg P ha− 1 year− 1. Leaves litterfall amount differed among tree species as influenced by tree species characteristics (canopy area, diameter at breast height (DBH), height), but no cause-effect relationship with age and climate (monthly precipitation and temperature).

中文翻译：

---

家庭花园混农林系统的四种多用途树/灌木树种的落叶量和养分输入

与天然森林生态系统相比，农业生态系统下的土壤更容易发生物理和生化属性的变化。但是，在这些农业生态系统中保留和/或种植的树种通过影响落叶量和质量来补充土壤肥力。从四种多用途树/灌木物种（Erythrina brucei Schweinf、Cordia africana Lam.、Grevillea robusta R. Br. 和 Malus）评估了树种相关的落叶量和季节性差异以及相关的营养元素年回报量sylvestris Mill.) 在家庭花园农林复合系统中。每个物种的两个叶子垃圾陷阱的五个重复被随机放置在亚冠层区域下方 12 个月，总共 40 个垃圾陷阱分布在四个物种中。这项研究的结果表明，每年树叶凋落物总量因物种而异（从 171.18 到 962 千克公顷- 1），每棵树平均每月（28.13 千克树- 1），每棵树每年平均（331.10 千克树- 1 年− 1) 和每个地区的年度总量 (9439.33 kg ha− 1) 落叶量。在本研究中观察到多用途乔木/灌木物种具有不同峰值的明显季节性落叶模式，E. brucei 和 C. africana 具有双峰分布模式，G. robusta 和 M. sylvestris 具有单峰分布模式。同样，来自叶子的养分浓度和输入᾽ litterfall 在物种之间显示出相当大的差异 (p < 0.05)。在调查的物种中，C. africana 和 E. brucei 被发现在碳 (C) 和氮 (N) 返回方面最好，G. robusta 在磷 (P) 返回方面最好，C. africana 在钾 (K) 返回方面也是最好的。所有物种记录的综合年平均养分输入量为 3125.32 kg C ha- 1 year- 1、149.70 kg N ha- 1 year- 1、54.86 kg K ha- 1 year- 1 和 3.56 kg P ha- 1 年− 1. 树种间落叶量受树种特征（冠层面积、胸径（DBH）、树高）的影响，与树龄和气候（月降水量和气温）无因果关系。