福建东山滨海沙地木麻黄林生态系统的能量特征

对福建东山县海岸带红壤性风积沙土与均一性风积沙土木麻黄群落的生物量、生产力、各组分干重热值、去灰分热值及能量分布与结构特征进行了研究.结果表明,红壤性风积沙土木麻黄群落的现存生物量和能量分别为1 681.84 g·m^-2和317 79.31 kJ·m^-2;均一性风积沙土木麻黄群落现存生物量和能量分别为 129.87 g^-1·m^-2和10 71.0kJ·m^-2;红壤性风积沙土的木麻黄群落各组分热值范围为19.84～21.70 kJ·g^-1,各组分能量在群落中所占比例为:干(38.09%)＞枝(19.48%)＞根(17.09%)＞叶(16.86%)＞皮(6.83%)＞枯枝(0.88%)＞果(0.77%),凋落物能量归还量为9 070.47 kJ·m^-2·yr^-1,群落能量的净固定量为31 298.70kJ·m^-2·yr^-1;均一性风积沙土木麻黄群落各组分热值在19.98～21.39kJ·g^-1,其中枯枝热值最高,根最低;各组分能量在群落中所占比例为:干(46.93%)＞根(16.44%)＞枝(13.92%)＞枯枝(12.28%)＞皮(5.87%)＞叶(3.90%)＞果(0.66%),凋落物能量归还量为2 061.77 kJ·m^-2·yr^-1,群落能量净固定量为12 662.82 kJ·m^-2·yr^-1.红壤性风积沙土上的木麻黄群落现存生物量和能量现存量均要高于均一性风积沙土,原因是红壤性风积沙土的沙土层薄(＜20 cm),土壤保水肥的能力要强于沙土层厚(＞100 em)的均一性风积沙土.

Energy characteristics of Casuarina equisetifolia ecosystem on coastal sand in Dongshan County,Fujian Province

The study on the energy characteristics of Casurina equisetifolia community on red earth eolian sandy soil and homogeneous eolian sandy soil in Dongshan County of Fujian Province showed that the standing biomass and energy of Casurina equisetifolia community were 15 681.84 g x m(-2) and 317 795.31 kJ x m(-2) on red earth eolian sandy soil, and 5 129.87 g x m(-2) and 10 575.50 kJ x m(-2) on homogeneous eolian sandy soil, respectively. On homogeneous eolian sandy soil, the gross caloric value of the community ranged from 19.98 kJ x g(-1) to 21.39 kJ x g(-1), of which, dead branch was the highest while root was the lowest, and its percentage was 46.93% (truck) > 16.44%(root) > 13.92% (branch) > 12.28% (dead branch) > 5.87% (bark) > 3.90% (leaf) > 0.66% (fruit). The return amount of litter was 2061.77 kJ x m(-2) x yr(-1), and the net energy productivity was 12662.82 kJ x m(-2) x yr(-1). On red earth eolian sandy soil, the gross caloric value was 19.84 - 21.70 kJ x g(-1), among which, leaf was the highest while root was the lowest, and its percentage was 38.09% (truck) > 19.48% (branch) > 17.09% (root) > 16.86% (leaf) >6.83% (bark) > 0.88% (dead branch) > 0.77% (fruit). The returned amount of litter was 9070.47 kJ x m(-2) x yr(-1), and the net energy productivity was 31 298.70 kJ x m(-2) yr(-1). The standing biomass and energy of Casurina equisetifolia community were higher on red earth eolian sandy soil than on homogeneous eolian sandy soil, mainly because red earth eolian sandy soil had a thinner sandy layer (< 20 cm) and a stronger nutrient and water supplying ability.