杉木根桩分解过程及几种主要营养元素的变化

基于以空间代替时间的原则,初步研究了杉木树桩在分解过程中边桩和心桩密度的变化及根桩分解过程中几种养分元素的释放过程.结果表明,边桩每年密度损失率k为2.767×10-2,而心桩为2.255×10-2;不同采伐年代的根系和边桩中N、P含量随分解年限的增加而下降,而心桩中N、P含量随分解年限的增加而出现先增加后下降的的趋势,根桩中K浓度在分解过程中的前两年有较大幅度的下降,根桩中有机质含量在其分解过程中都是单调降低的,对根系和树桩中养分元素含量进行比较发现,在分解初期,根系中N、P、K含量都高于边桩和心桩,而有机质含量边桩和心桩高于根系

Decomposition process of Chinese fir stump roots and changes of nutrient concentration

With space as a substitute for time, the changes of the density of stump sapwoods and heartwoods, and the releasing process of major nutrients during the decomposition of Chinese fir stump roots were investigated. The yearly loss rate of the densities of sapwoods and heartwoods was 2.767 x 10(-2) and 2.255 x 10(-2) respectively during decomposition. The contents of N and P in sapwoods and roots decreased continually, while those in heartwoods increased during the first stage of decomposition, and then decreased. The K concentration in stump roots decreased remarkably during first two years, and the content of organic substances decreased during the whole decomposition process. The N, P and K concentrations in roots, were higher than those in stump sapwoods and heartwoods at the beginning of decomposition, but bet content of organic substance was opposite.