桂西北杉木成熟林营养元素积累及其分布格局
Nutrient Accumulation and Distribution of Mature Cunninghamia lanceolata Plantation Ecosystem in Northwestern Guangxi

为了探究桂西北杉木人工林成熟林的营养元素积累及其分布格局，为该区域杉木人工林的经营管理提供依据。以广西南丹县30年生杉木林为研究对象，对其5种营养元素(N、P、K、Ca和Mg)含量、积累及其分配格局进行了研究。结果表明：1) 杉木中不同器官营养元素含量因器官不同而存在差异，以树叶最高，其次是树枝、干皮和树根，干材最低；林木中不同器官营养元素含量为N > K 或 Ca > Mg > P。2) 杉木成熟林营养元素总储量为955.06 kg？hm^？2，其中乔木层占91.15%，灌草层和凋落物层分别占0.98%和7.89%。3) 杉木成熟林乔木层营养元素年净积累量为29.01 kg？hm^？2？a^？1，每积累1 t干物质需要5种营养元素5.10 kg。
In order to understand the nutrient accumulation and distribution of the mature Cunninghamia lanceolata plantation in northwestern Guangxi, and to provide scientific basis for the management of the C. lanceolata plantation, the field nutrition content, accumulation amount, annual net accumulation and distribution characteristics of five nutrient elements (N, P, K, Ca and Mg) on the mature C. lanceolata plantation were studied. The results show that the contents of the five nutrient elements in different organs of C. lanceolata. The results show that: 1) The nutrient contents in various organs of C. lanceolata was in the order of leaves > branch, bark or root > stem. The content of N was the highest among the five elements, followed by Ca and K and Mg, while P was the lowest in various organs of C. lanceolata. 2) The total storage of five nutrient elements in the mature C. lanceolata plantation was 955.06 kg？hm^？2, of which arbor layer, overstorey (shrub and herb layer) and litter layer accounted for 91.15%, 0.98%, 7.89% and 4.58% respectively. 3) The annual net accumulation of nutrients of the C. lanceolata plantation was 29.01 kg？hm^？2？a^？1, and for every ton of dry matter production needed 5.10 kg of the five elements.