The characteristics of soil basal fertility in mountainous region of Shennongjia

In order to understand the basal characteristics of soil basal fertility in mountainous region of Shennongjia,we collected 156 soil samples during more than 20 days of field investigation in Shennongjia region.Thereafter,soil gravel content,pH,organic matter,alkali-hydrolyzable N,available P,available K was determined.The results showed that the value of above indexes had wide variation scope and various features.The gravel contents ranged from 0 to 87% in soil in Shennongjia region and the soil with more than 10% of gravel content counted up 65.4% of the total soil samples.Soil value of pH was within the scope of 3.8-8.0,but 73.1% of soil in Shennongjia region was acid or highly acid soil and there was no strongly alkaline soil in this area.The soil organic matter ranged from 1.9 to 144.0 g kg-1 and the soil rich in organic matter contributed 50% of the total.The variation scope of alkali-hydrolyzable N,available P and available K was respectively within 26-766,1.8-115.3 and 16-399 mg kg-1,and the soil rich in alakali-hydrolyzabe N was made up 67.3% of total soil samples,but the soil rich in available P was no more than 20% of the total,while 63% of soil was lack of available P.Soil rich in and lack of available K counted up about 30% of the total respectively.The correlation analysis indicated that there was significantly linear relationship between each other among the contents of soil organic matter,alkali-hydrolyzable N,available P and available K,but among the relationship coefficients of organic matter to alkali-hydrolyzable N,available P and available K,it was highest to alkali-hydrolyzable N and lowest to available P.In conclusion,the soil in Shennongjia mountain area was rich in gravels,organic matter and alkali-hydrolyzable N,lacking of available P and had a medium level of available K,tanking on acidity mostly.