首页|期刊导航|中国农业科学（英文版）|Soil Properties and Characteristics of Soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China
中国农业科学（英文版）2007，Vol.6Issue(6)：706-714,9.
Soil Properties and Characteristics of Soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China
Soil Properties and Characteristics of Soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China
摘要
Abstract
The composition and stability of soil aggregate are closely related to soil quality, soil erosion, and agricultural sustainability. In this study, 49 soil samples at the 0-10 cm surface layer were collected from four soil types (i.e., Ari-Sandic Primosols, Calci-Orthic Aridosols, Siltigi-Otrthic Anthrosols, and Ustic Cambosols) in the marginal farmland in the oasis of the middle Hexi Corridor region and was used to determine the characteristics of soil aggregates. The composition of dry- and wet- sieved aggregates and the physical and chemical properties (including soil particle distribution, soil organic carbon (SOC), calcium carbonate (CaCO3), and oxides of Fe3+ and Al3t) of the selected soils were analyzed. The results show that soil particle size distribution is dominated by fine sand fraction in most of soils except Ustic Cambosols. Soil organic carbon concentration is 5.88±2.52 g kg-1 on average, ranging from 4.75 g kg-1 in Ari-Sandic Primosols to 10.51 g kg-1 in Ustic Cambosols. The soils have high calcium carbonate (CaCO3) concentration, ranging from 84.7 to 164.8 g kg-1, which is increased with soil fine particle and organic carbon content. The percentage of ＞0.25 mm dry aggregates ranges from 65.2% in Ari-Sandic Primosols to 94.6% in Ustic Cambosols, and large dry blocky aggregates (＞5 mm) is dominant in all soils. The mean weight diameter of dry aggregates (DMWD) ranges from 3.2 mm to 5.5 mm. The percentage of ＞0.25 mm water-stable aggregate is from 23.8% to 45.4%. The percentage of aggregate destruction (PAD) is from 52.4% to 66.8%, which shows a weak aggregate stability. Ari-Sandic Primosols has the highest PAD. The distribution and characteristics of soil aggregates are in favor of controlling soil wind erosion. However, the stability of aggregate of all soils is weak and soils are prone to disperse and harden after irrigation. The mass of macro-aggregates and DMWD are positively significantly correlated with the contents of soil clay and silt, soil organic carbon (SOC), CaCO3, and oxides of Fe3+ and A13+. Soil fine silt and clay, SOC and CaCO3 are important agents of aggregation in this region, and the effect of SOC and CaCO3 on aggregate stability is more significant than that of soil silt and clay. Converting cropland to alfalfa forage land can increase SOC concentration, and in turn, enhance the formation of aggregates and stability. For the marginal farmlands in this fragile ecological area, converting cropland to alfalfa grassland or performing crop-grass rotation is an effective and basic strategy to improve soil structure and quality, to mitigate soil wind erosion, and to enhance oasis agricultural sustainability.关键词
soil aggregate/soil properties/returning cropland to grassland/marginal oasis/Hexi Corridor regionKey words
soil aggregate/soil properties/returning cropland to grassland/marginal oasis/Hexi Corridor region分类
农业科技引用本文复制引用
SU Yong-zhong,WANG Fang,ZHANG Zhi-hui,DU Ming-wu..Soil Properties and Characteristics of Soil Aggregate in Marginal Farmlands of Oasis in the Middle of Hexi Corridor Region, Northwest China[J].中国农业科学（英文版）,2007,6(6):706-714,9.基金项目
This work was supported by the National Natural Science Foundation of China (30670375) and the Knowledge Innovation Program from Chinese Academy of Sciences (KZCX2-XB2-04). （30670375）
