福建侵蚀坡地果园龙眼凋落物的年变化及库流量

Annual variation of Longan litter fall and the annual flows on eroded slope orchard of Fujian

为了了解侵蚀坡地生态果园的物质和能量流动,研究了福建侵蚀坡地果园龙眼凋落物年变化规律和凋落物的养分含量和年库流量。结果表明:龙眼果树年凋落量为48.513kg/株,叶、枝、花和果分别占32.41%、13.15%、1.97%和52.47%;龙眼果树月凋落量季节变化规律是单峰型的,8月凋落量为29.115kg,与其他月份之间有显著差异,占全年的60.01%。凋落叶N、P、K含量季节变化大于Ca和Mg,Ca、Mg季节间变化不明显。通过龙眼凋落物归还的年库流量为697.91kg/hm2。凋落物中5种养分中,年库流量大小顺序为Ca>K>Mg>P>N((446.02>115.73>74.31>37.47>24.39,kg/hm2),各元素的含量所占比例,凋落叶78.59%,枝14.88%,果3.54%,花2.99%。果树叶片凋落前因N、P、K迁移而导致落叶中N、P、K浓度比成熟叶的低,但三者存在着元素间的差异,Ca不迁移,Mg有月份间差异;果树叶片凋落前,N、P、K的年回流量分别为7.420、6.374、53.152kg/hm2,9月份回流量最多,分别为3.632、3.762和21.920kg/hm2。

Seasonal dynamics and nutrient concentrations in litter fall and the annual flows of N, P, K, Ca and Mg were studied in Longan orchard systems on eroded slope orchard of Fujian. The result showed that annual litter fall of them were 48.153kg.The percentage of tree, leaf, branch, flower and fruit is 32.41%, 13.15%, 1.97% and 52.47% respectively. There is single litter fall peak in August and the amount is 29.115?kg, amounting to 60.01% of whole year. Variation of N, P and K content is smaller than Ca and Mg content in leaf litter fall. The annual flows of N, P, K, Ca and Mg by litter fall were 697.91?kg/hm^2 and its order is as follows: Ca>K>Mg>P>N(446.02>115.73>74.31>37.47>24.39, kg/hm^2). The orchard achieve cycles of them by leaf and fruit mainly. The concentrations of N, P and K in the leaves after falling are lower than mature leaves, because those elements transfer before leaf falling, but there are differences among three elements that Ca doesn't transfer in the leaves and the movement of Mg has differences in different months. Annual return amounts of N, P and K before the leaves falling is7.420, 6.374 and 53.152?kg/hm^2, the most return amounts of which is3.632, 3.762, and 21.920?kg/hm^2 in September respectively.