Chin J Plant Ecol ›› 2008, Vol. 32 ›› Issue (3): 601-610.DOI: 10.3773/j.issn.1005-264x.2008.03.009

• Original article • Previous Articles     Next Articles

VARIATIONS OF SOIL PARTICLE SIZE DISTRIBUTION WITH LAND-USE TYPES AND INFLUENCES ON SOIL ORGANIC CARBON AND NITROGEN

TIAN Jia-Qian1,4, ZHOU Zhi-Yong2, BAO Bin3, SUN Jian-Xin2,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2Key Laboratory for Silviculture and Conservation of Ministry of Education, College of Forest Science, Beijing Forestry University, Beijing 100083, China
    3Hulunbeir Forest Research Institute, Hailar, Inner Mongolia 021008, China
    4Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2007-03-22 Accepted:2007-06-11 Online:2008-03-22 Published:2008-05-30
  • Contact: SUN Jian-Xin

Abstract:

Aims In this study, variations of soil particle size distribution and correlations with soil C and N were studied on sites representing six different land-use types in the steppe grasslands of Inner Mongolia, Northern China. The six land-use types are grazing exclusion by fencing (GE), mowing (MW), free grazing (FG), fallow (FL), alfalfa pasture (AP), and corn plantation (CP). Our objectives were to: (a) assess variability of soil particle size distribution across different land-use types in the steppe grasslands of northern China and (b) examine correlations of soil particle size distribution with soil C and N as affected by land-uses.

Methods Twenty-four sampling plots, each 30 m×30 m, were established on sites representing the six land-use types. Measurements were made on soil particle size distribution, aboveground biomass, root biomass, litter, soil organic carbon (SOC) and soil total nitrogen (TN) in the 0-10, 10-20 and 20-30 cm soil layers. Data were evaluated by one-way analysis of variance and correlation analysis using SPSS. Fractal dimension of soil particle size distribution was calculated using the method of Yang et al. (1993).

Important findings Fractal dimension of soil particle size distribution was lowest in the FG among the six land-use types. Soil clay (<0.005 mm) and silt (0.005-0.05 mm) content of the FL and AP were consistently higher than the other four land-use types; whereas those of the FG were consistently lower. Clay and silt content decreased with soil depth except for the AP and FG. Soil sand content was significantly negatively correlated withSOC and TN for all land-use types, while soil clay content was significantly positively correlated with SOC and TN except for FG and AP. Regardless of the land-use types, root biomass was found to be significantly positively correlated with SOC, TN and soil clay and silt content. Aboveground biomass and litter were significantly positively correlated with only clay content. Root biomass and clay content together explained 70% of the variance in SOC and soil TN, and separately only 20% of the variance each. The relationships were best described as: SOC = 1.08 × clay% + 0.01 × biomass roots-19.45,TN=0.079×clay%+0.001×biomassroots-1.143. Findings indicate that land-use types can have significant effects on soil physical properties as well as SOC and soil TN and consequently alter the relationships of soil particle size distribution with SOC and soil TN.

Key words: land-use, soil texture, grassland, fractal dimension analysis, correlation analysis