宜昌地区土壤有机质的空间分布及演变特征

对宜昌地区13个典型土壤剖面土壤有机质进行了测定和统计分析。结果表明,宜昌地区土壤有机质表现出显著的空间变异性。在水平分布上,西部高山区土壤有机质最为丰富,高山棕壤土0～10 cm土层有机质含量可达到77.72 g/kg;中部低山丘陵区土壤养分缺乏,尤其是耕种后的红壤土0～10 cm土层有机质含量仅有2.83 g/kg;东部河谷平原区土壤有机质相对较高,水稻土表土层有机质含量为27.10g/kg。在垂直分布上,大多土壤剖面有机质都表现出显著的表聚性,并且黄棕壤、棕壤2种地带性土壤以及非地带性土壤中的潮土表现出明显的从表层往下有机质依次递减的规律。近30年来,宜昌地区土壤有机质整体上出现一定的退化特征,其中黄壤与红壤的退化特征尤为明显,0～10 cm土层有机质分别下降39.9%和54.7%。

Study on the Spatial Distribution and Evolution of Soil Organic Material Content in Yichang District

Soil organic matreial(SOM) samples from 13 typical soil profiles in Yichang area were measured and analysed.The results showed that SOM content showed a significant variation in spatial distribution.In the horizontal distribution,SOM content in the west mountainous area ranked the highest;and that in mountainous brunisolic soil at the 0～10 cm depth reached to 77.72 g / kg.Soil nutrient was low in the middle hilly region and SOM content in the cultured red loam soil at the 0～10 cm depth was only 2.83 g / kg;SOM content in the east valleyed plain area was relatively high;and that of top paddy soil was 27.1 g / kg.SOM content at most sites showed significant surface accumulation character in the vertical distribution.The profile distribution of SOM content of 2 zonal soil,yellow brown soil and brown soil,and a non-zonal soil,moisture soil generally presented a declining trend from up to down.There was a general degeneration sign in SOM content in Yichang area during the last 30 years,especially yellow soil and red loam soil,of which the SOM content in the 0～10 cm depth had decreased by 39.9% and 54.7%,respectively.