速生阶段秃杉与杉木人工林营养元素积累及其分配特征

Nutrient accumulation and distribution in Taiwania flousiana and Cunninghamia lanceolata plantation

对广西南丹山口林场相似立地条件下速生阶段(11年生)的秃杉与杉木(第2代)人工林5种营养元素(N、P、K、Ca和Mg)的含量、积累量、年净积累量和分配进行了研究。结果表明,秃杉与杉木不同器官中营养元素含量排序均为树叶>干皮>树枝>树根>干材,林木各器官营养元素含量均以N最高,其次是Ca和K,Mg和P最低。秃杉人工林分营养元素贮存量为573.40kg.hm-2,明显高于杉木人工林(330.33kg.hm-2),其中乔木层、林下植被层和凋落物层分别为517.97、11.05和47.05kg.hm-2,分别占林分营养元素积累量的89.91%、1.92%和8.17%。5种营养元素贮存量在秃杉与杉木人工林乔木层的分配均为树叶>树枝>干材>干皮或树根。秃杉人工林营养元素平均年净积累量为47.09kg.hm-.2a-1,是杉木人工林(26.55kg.hm-.2a-1)的1.77倍。秃杉的营养元素利用效率低于杉木,但明显高于马尾松、刺槐和马占相思。

The contents,accumulation,annual net accumulations and distribution of five nutrient elements （N,P,K,Ca and Mg） in Taiwania flousiana and Cunninghamia lanceolata （the second generation） plantation at fast growing stage （11-year-old） of same habitats were studied in Nandan Shankou Forestry Farm of Guangxi,China.The results showed that the nutrient content in various organs of T.flousiana and C.lanceolata was in the order of leavesstem barkbranchrootstem wood.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 T.flousiana and C.lanceolata.The total nutrient storage of T.flousiana plantation was 573.40 kg·hm^-2,which was evidently higher than that of C.lanceolata plantation （330.33 kg·hm^-2）,of which overstorey of T.flousiana trees stored 517.97 kg·hm^-2 and accounted for 89.91%,and forest floor stored 11.07 kg·hm^-2 and accounted for 1.92%,and standing litter stored 47.09 kg·hm^-2 and accounted for 8.17%.The amount of nutrient elements in different parts of trees was in the order of leavesbranchstem woodstem bark or root for T.flousiana and C.lanceolata plantation.Nutrient annual net accumulation in T.flousiana plantations was 47.09 kg·hm^-2·a^-1,1.77 times as great as that of the C.lanceolata plantations （26.55 kg·hm^-2·a^-1）.The nutrient utilization efficiency of T.flousiana plantations was lower than that of C.lanceolata plantations,but evidently higher than that of Pinus massoniana,Robinia pseudoacacia and Acacia mangium plantations.