摘要：Soil polarization is a new concept which describes the deviation of soil properties of planted pure forest fromits original equilibrium status towards an extreme condition due to long-term growth or continuous planting ofsingle tree species. It is thought to be one obstacle of forest. In order to investigate the effect of litterdecomposition on soil polarization of planted forests in the gully region of Loess Plateau, China, humus soiland litter were sampled in two typical broadleaved forests, and 4 treatments as “soil + leaf litter”, “soil +roots”, “soil + leaf litter + roots”, and CK were set for laboratory incubation experiment in this research. Theresults showed that polarizations of different properties were variable, in both direction and degree, after theincubation with litters. Based on analyzing the polarization ratios by PCA (principal component analysis)method, the results of comprehensive soil properties were showed as follows: in the Robinia pseudoaciaforest soil, both of leaf litter and roots resulted in negative polarization, and leaf litter showed greater effectthan roots; in the Betula platyphylla forest soil both of leaf litter and roots resulted in negative polarization,and also leaf litter showed greater effect than roots. When leaf litter and roots mixed-together with the soil,the interaction sequence is R. pseudoacia (0.497) > B. platyphylla (-0.466). The result indicated that leaflitter and roots when mix-incubated with forest soil showed promoting effect on soil properties in the R.pseudoacia forest soil, and showed inhibitory effect on soil properties in B. platyphylla forest soil. In general,litter decomposition in R. pseudoacia forest soil was more beneficial for soil properties than B. platyphylla.
