东南沿海沙地2种人工林营养元素生物循环

Biological Cycling of Nutrient Elements of Two Plantations in Southeast Coastal Area,China

对闽东南滨海沙地8年生卷荚相思和木麻黄人工林5种营养元素(N、P、K、Ca、Mg)的质量分数、积累、分配和生物循环进行研究。结果表明,卷荚相思和木麻黄林5种营养元素质量分数以树叶为最高,干材最低,林木各器官营养元素质量分数排序均为N>Ca>K>Mg>P;营养元素总积累量分别为282.79kg·hm-2和1 160.25kg·hm-2;各器官营养元素积累量卷荚相思林为枝>干>皮>叶>根,木麻黄林为叶>枝>干>皮>根;各营养元素积累量排序,卷荚相思林为N>K>Ca>Mg>P,木麻黄林为N>Ca>K>Mg>P;养分年存留量分别为35.35、140.61kg·hm-2·a-1,年吸收量为97.01kg·hm-2·a-1和312.65kg·hm-2·a-1,总归还量为61.66kg·hm-2·a-1和172.04kg·hm-2·a-1。卷荚相思和木麻黄林营养元素的循环系数分别为0.64和0.54,利用系数分别为0.34和0.27,周转期分别为4.59a和6.74a;各营养元素利用系数和循环速率均为Mg>Ca>N>P>K,周转期则相反。卷荚相思林5种营养元素利用系数、循环速率均高于木麻黄林,而周转期均低于木麻黄林,有利于林地养分维持。P可能是限制卷荚相思生长关键营养元素之一,因此应采取施P肥等措施以提高林地生产力。

Standard plot method was used to study the concentration,accumulation,distribution and biological cycling of five nutrient elements（N,P,K,Ca,Mg）of 8-year-old Acacia cincinnata plantation（AP）and Casuarina equisetifolia plantation（CP）on a sandy coastal plain soil in southeast Fujian Province,China.The results showed that nutrient contents in the leaves were the highest among those in different organs of AP and CP,with the lowest in the stems.In these plantations,concentration of N was the highest among the five elements,followed by Ca,K and Mg,while P was the lowest in various organs.The total nutrient accumulations were 282.79 and 1 160.25kg·hm-2 in pure AP and CP,respectively.The nutrient accumulation of various organs was ranked as branchesstems barksleavesroots in the AP and leaves branches stemsbark roots in the CP.Changes in accumulation of various nutrients in AP（NKCaMgP）,which were different from CP（NCaKMgP）.Annual net nutrient accumulation,return and absorption were 35.35 and 140.61kg·hm-2·a-1,61.66 and 172.04kg·hm-2·a-1 and 97.01 and 312.65kg·hm-2·a-1 in the AP and CP.Nutrient cycling coefficient,the utilization coefficient and the recycling period of AP and CP were 0.64 and 0.54,0.34 and 0.27,4.59and6.74 a,respectively.The utilization coefficient and cycling coefficient of five nutrient elements were MgCaNPK in these plantations,and higher in AP than CP,soil fertility and the nutrient supply were improved in AP.Phosphorus was a key nutrient element for A.cincinnatagrowth,therefore it should be taken to improve the forest productivity of P fertilizer.