滨海沙地纹荚相思人工林凋落物及养分归还动态研究

Litterfall Production and Nutrient Return Dynamics of Acacia aulacocarpa Plantation in a Coastal Sandy Plain Area

2011年10月至2012年9月,通过对福建长乐滨海沙地纹荚相思人工林凋落物量进行为期12个月的定位监测,并对凋落物养分特征及归还动态进行研究。结果表明,纹荚相思人工林年凋落物量为5.3 t/hm2,具有明显的季节动态,呈单峰型,最大值出现在2012年6月;叶子是凋落物的主要形式,占总凋落物量的67.85%,其次是落枝、杂叶、碎屑、杂果、落果、花、杂枝、皮;5种营养元素在凋落物中的平均含量大小表现为N>K>Ca>Mg>P。5种元素的年通量大小为127.98kg/(hm2·a),其中氮元素年通量最大,为75.63 kg/(hm2·a),磷元素年通量最小,为2.24kg/(hm2·a);纹荚相思人工林叶凋落物N、P、K、Ca、Mg 5种养分元素的归还动态模式相似,归还量均在7月达到最大值,Fe、Mn、Zn、Cu 4种微量元素的年归还量为1.272、2.261、0.192、0.023kg/(hm2·a)。凋落物各组分中微量元素Mn含量最高,其次是Fe、Zn,而Cu最低。

A twelve-month field study was conducted to measure litterfall production and its nutrient return characteristics of a Acacia aulacocarpa plantation forest in a coastal sandy plain area from October 201 1 to Septem-ber 2012 in Changle,Fujian.The results showed that the annual litterfall production in the studied plantation site was 5. 3 t/hm2,the quantity of the litterfall dynamically changed along the seasons,expressing ‘single peak’in June 2012.Leaf litter was the main component and accounted for 67. 85%of total amount,followed by branches, miscellaneous leaves,debris,miscellaneous fruits,fruits,flowers,miscellaneous branches and bark.The average concentrations of 5 macronutrient elements in the litterfall decreased in the following order N 〉K〉Ca〉Mg〉P. The fluxes of these 5 macronutrient elements in the litterfall was 127. 98 kg/（hm2 ·a）,the annual flux of nitrogen was maximum,which content was 75. 63 kg/（hm2 ·a）;and the annual flux of phosphorus was minimum,which content was 2. 24 kg/（hm2 ·a）.These 5 macronutrient return patterns were similar,and reached the maximum in July,the annual returns of these four trace elements （Fe、Mn、Zn、Cu ）were 1. 272 kg/（hm2 · a ）, 2. 261 kg/（hm2·a）,0. 192 kg/（hm2·a）,0. 023 kg/（hm2·a）.In plant of litterfall,concentration of Mn was the highest among the four elements,followed by Fe,Zn,while Cu was the lowest in various components of Acacia aulacocarpa plantation.