The Study On The Biomass Carrying Capacity Of Devolution Mountain In Hebei

In this thesis, the gneiss devolution mountain in Tang county and purple sandshale , granite devolution mountain in ManCheng county were studied. In order to find a valid way to fit for exploitation and meliorate of devolution mountain in Hebei, model, sampling and analysis were used to study the status of trends of nutrients accumulating , biomass and biomass carrying capacity of devolution mountain which was undeveloped , developed for 4 years and developed for 7 years. The results showed as follows:1. Ideal value of NPP of natural vegetation is 6.75 t·hm^-2·a^-1(dry substance) in representative experimentation area of devolution mountain in Hebei. The results of unsuitable management and soil erosion have deteriorated the living conditions of biology, which result in the decreasing of Biomass Carrying Capacity obviously.2. The region of gneiss: The amount of soil granule (>1mm) of Treat 3 have decreased by 14.6% than that of treat 2; the depth of soil layer has increased by 60cm⁸0cm; the gross of soil moisture has improved by 2.5 and 3.1 times; the soil pH have a decreasing trend gradually; the soil organic matter and available nutrition (available N, available P and available K) have increased obviously. The biomass of treat 2 and 3 has improved by 1.7 and 5.3 times than that of treat 1, and the difference is significant.3.The region of purple sandshale: The amount of soil granule (>1mm) of Treat 2, 3 have decreased by 18.29% and 29.49% than that of treat 1 respectively; the depth of soil layer has increased by 40cm⁵0cm; the gross of soil moisture has improved by 2.5 and 2.8 times; the soil pH have a decreasing trend gradually; the soil organic matter and available nutrition (available N, available P and available K) have increased significantly. The biomass of treat 2 and 3 has improved by 2.5 and 8.7 times than that of treat 1,and the difference is significant.4. The region of granite: The amount of soil granule (>1mm) of Treat 2, 3 have decreased by 22.13% and 41.18% than that of treat 1 respectively; the depth of soil layer has increased by 30cm⁴0cm; the gross of soil moisture has improved by 1.0 and 0.9 times. The soil pH have a decreasing trend gradually, however, the decreasing speed is slower than that of the region of purple sandshale and gneiss. The soil organic matter and available nutrition (available N, available P and available K) have increased significantly. The biomass of treat 2 and 3 has improved by 1.0 and 4.1 times than that of treat 1.The...