黄土高原不同树种枯落叶混合分解效应

混交林中不同树种枯落物混合分解是否产生促进或抑制作用是评价种间关系和混交适宜性的重要依据之一。以黄土高原主要树种为对象,通过室内枯落叶混合分解模拟试验,结果表明:(1)沙棘、白榆、柠条和小叶杨枯落叶分解最快(周转期1 a左右),其次为旱柳、侧柏和白桦枯落叶(周转期略大于1 a),紫穗槐、辽东栎和刺槐枯落叶分解稍慢(周转期1.5 a左右),而樟子松、落叶松和油松枯落叶分解最慢(周转期略大于2 a)。(2)对于针叶树,与油松枯落叶混合,存在明显促进分解作用的是侧柏、落叶松,其次是白桦、沙棘和刺槐;与樟子松枯落叶混合,存在明显促进分解作用的是落叶松、侧柏、沙棘、白榆,其次是柠条、紫穗槐和小叶杨,而存在明显抑制分解作用的是刺槐,其次是白桦和辽东栎;与落叶松枯落叶混合,存在较明显促进分解作用的是白榆、白桦和辽东栎,存在较明显抑制作用的是刺槐;紫穗槐与侧柏枯落叶混合存在较明显的抑制分解作用。(3)对于阔叶树,与小叶杨枯落叶混合,存在较明显促进分解作用的是紫穗槐,其次是辽东栎和刺槐;与刺槐枯落叶混合,存在较明显促进分解作用的是白榆和沙棘,存在明显抑制分解作用的是柠条,其次是辽东栎和白桦;与白桦枯落叶混合,存在较明显促进分解作用的是辽东栎和紫穗槐,存在较明显抑制分解作用的是柠条;白榆与辽东栎、旱柳枯落叶混合均存在较明显的促进分解作用,而白榆与柠条枯落叶混合存在较明显的抑制分解作用;紫穗槐与旱柳、沙棘枯落叶混合均存在较明显的促进分解作用,而紫穗槐与柠条枯落叶混合有较明显的抑制作用。

Effects of mix-leaf litter decomposition of different trees in the Loess Plateau

Effects of mix-leaf litter decomposition of different trees are important bases of evaluating interspecific relationship and mix-foresting suitability of trees. Experiments of mix-leaf litter decomposition between main tree species in the Loess Plateau have been carried out in laboratory and the results show that:(1)Leaf litter of Hippophae rhamnoides, Ulmus pumila, Caragana microphylla and Populus simonii decompose the most quickly(Turnover periods Ts are 1a around),leaf litter of Salix matsudana, Platycladus orientalis and Betula platyphylla decompose the second quickly(Ts are a little longer than 1 a),leaf litter of Amorpha fruticosa, Quercus liaotungensis and Robinia pseudoacacia decompose a little slowly(Ts are 1.5 a around),leaf litter of Pinus sylvestris var. mongolica, Larix principis-rupprechtii and Pinus tabulaeformis decompose the most slowly(Ts are a little longer than 2 a).(2)For needle-leaved trees, mixed with litter of P. tabulaeformis, the trees most obviously promoting decomposition are P. orientalis and L. principis-rupprechtii, followed by B. platyphylla, H. rhamnoides and R. pseudoacacia, and no trees obviously restraining decomposition. Mixed with litter of P. sylvestris var. mongolica, the trees most obviously promoting decomposition are L. principis-rupprechtii, P. orientalis, H. rhamnoides and U. pumila, followed by C. microphylla, A. fruticosa and P. simonii, but the trees most obviously restraining decomposition are R. pseudoacacia followed by B. platyphylla and Q. Liaotungensis. Mixed with litter of L. principis-rupprechtii, the trees most obviously promoting decomposition are U. pumila, B. platyphylla and Q. liaotungensis, but the tree obviously restraining decomposition is R. pseudoacacia. A. fruticosa would obviously restraining decomposition mixed with litter of P. orientalis. (3)For broad-leaved trees, mixed with litter of P. simonii, the trees most obviously promoting decomposition are A. fruticosa followed by Q. liaotungensis and R. pseudoacacia. Mixed with litter of R. pseudoacacia, the trees most obviously promoting decomposition are U. pumila and H. rhamnoides, the trees obviously restraining decomposition are C. microphylla followed by Q. liaotungensis and B. platyphylla. Mixed with litter of B. platyphylla, the trees most promoting decomposition are Q. liaotungensis and A. fruticosa, the tree obviously restraining decomposition is C. microphylla. U. pumila would obviously promote decomposition mixed with litter of Q. liaotungensis or S. matsudana, but U. pumila would restrain decomposition mixed with litter of C. microphylla. A. fruticosa would promote decomposition mixed with litter of S. matsudana or H. rhamnoides, but restrain decomposition mixed with litter of C. microphylla.