桤木人工林营养元素的季节动态、空间分布与生物循环研究  

Seasonal Variation,Distribution and Biological Cycling of Nutrient Element of Plantation in Alnus cremastogyne

作　　者：文仕知[1] 黄采艺[1] 杨丽丽[1] 何功秀[1] 

机构地区：[1]中南林业科技大学林学院,长沙410004

出　　处：《水土保持学报》2012年第6期96-101,共6页Journal of Soil and Water Conservation

基　　金：国家林业局重点项目(2008-12)

摘　　要：对湖南汨罗桤木人工林5种营养元素(N、P、K、Ca、Mg)的季节动态、空间分布及生物循环进行研究。结果表明:桤木叶片营养元素含量均为春季最高,干材养分含量偏低,且大部分元素在春季达最低点,所以建议桤木干材在春季采伐;树皮有大量Ca富集,根系中营养元素季节变化不明显。林下植被元素含量从春季到冬季有下降的趋势,枯落物、土壤层中元素含量季节变化趋势不明显,K元素各个土层各个季节含量变化都不是很大。桤木人工林生态系统各组分养分含量变化差异较大,以树叶中养分含量最高,30-60cm土壤层中含量最低;乔木层各器官排序为树叶>树皮>树枝>树根>树干,各器官中养分元素含量以N最高,P最低。桤木人工林生态系统养分总贮量为167 809.80kg/hm2,其中乔木层5种元素总量为754.77kg/hm2,占生态系统养分总贮量的0.45%,林下植被与枯落物层二者的养分积累量为254.04kg/hm2,占生态系统养分总贮量的0.15%。营养元素的年积累量为350.18kg/hm2,以N的积累量最大。桤木年吸收量、归还量、存留量分别为449.38,348.23,101.15kg/hm2。营养元素的循环系数为0.77,利用系数为0.60,周转期为2.17年,循环速率依次为N>Ca>Mg>K>P。The seasonal variation,distribution and biological cycling of 5 nutrient elements（N,P,K,Ca and Mg） in Alnus cremastogyne plantation in Miluo county were investigated.The results showed that element contents of A.cremastogyne leaves could reach the maximum in spring.It was proposed that A.cremastogyne trunk should be harvested in spring for the low content of nutrient elements,at the same time most elements reached the lowest point;Ca was enriched in bark and seasonal nutrient elements in roots did not change significantly.The element contents of the understory declined from spring to winter,meanwhile,nutrient elements had no obvious seasonal trends in litter and soil layer,and there were no significant changes of K contents in soil.In A.cremastogyne plantation,nutrient contents were different in different organs.The highest nutrient content was in the leaves,and the lowest was in the 30-60 cm soil layer.The element contents of different organs varied in the following order： Leaves〉 bark〉 branches 〉roots 〉trunk,and the N content was the highest,P content was the lowest.The total accumulation of nutrients in A.cremastogyne plantation were 167 809.80 kg/hm2,in which 5 elements in the tree layer was 754.77 kg/hm2（0.45% of the total nutrient accumulation）,and under-storey and litter layer accumulation of nutrients were 254.04 kg/hm2（0.15% of the total nutrient accumulation）,respectively.The annual accumulation of nutrient elements in A.cremastogyne plantation were 350.18 kg/（hm2·a）,in which N accumulation was the largest.The amount of absorption,return and retention of nutrient contents in the plantation were 449.38,348.23,101.15 kg/（hm2·a）,respectively.The nutrient utilization coefficient and circulation coefficient were 0.77 and 0.60,turnaround period was 2.17 years,respectively,and the cycling speed was： N 〉Ca〉 Mg〉 K〉 P.

关 键 词：桤木人工林 营养元素 季节动态 空间分布 生物循环 

分 类 号：S158.3[农业科学—土壤学]