Investigation On The Physical And Chemical Properties Of Soils In Xishuangbanna Tropical Botanical Garden

Xishuangbanna Tropical Botanical Garden(XTBG), Chinese Academy of Science, famous for its largest area and preserving the most species in China, is a blend of scientific research, species preservation and science education. We mainly used the grid sampling method to accumulate soil samplings. The number of soil samplings was 1039. We analyzed the physical and chemical properties of soils, builded the soil database for XTBG and mapped the spatial pattern of the soil nutrients, then some suggestion was provided based on its current condition, all of which provided the scientific foundation for the management and future development plan of XTBG., the main results were as follows:(1) The soil bulk density in XTBG is between 0.73g/cm3-1.78 g/cm3, pH value is between3.55-8.74, Alkaline-hydrolyzable nitrogen content is between 2.82mg/kg-318.47mg/kg.(2) The soil organic content at the west of the garden is between 1.01g/kg-25.62 g/kg, with its mean 9.25 g/kg. The content of total nitrogen, total phosphorus, total potassium, and available potassium are 0.03 g/kg-2.58 g/kg, with its mean 1.07 g/kg, 0.16 g/kg -1.17 g/kg, with its mean0.44 g/kg,4.98 g/kg-25.32 g/kg, with its mean 13.48 g/kg,20.00mg/kg-704.00 mg/kg, with its mean 78.49 mg/kg respectively. Except the variation coefficient of available potassium is 76.90, all the other nutrients are between 33.64-41.27.(3) The statistic results showed that the total potassium was insignificant correlated with soil organic matters, total nitrogen and alkaline nitrogen as well as that of total phosphorus was insignificant with pH value. There was significant associated relationship between that of the other soil nutrients, between which pH value was extremely significant negative correlated with soil organic matters, total nitrogen and alkaline nitrogen. The total potassium was significant positive correlated with available potassium, and there was significant positive correlated between others.(4) The soil nutrients were significantly different in soil under lawn and soil covered with litter except total phosphorus. Soil under lawn that soil bulk density, pH, water content of fresh soil and the potassium content were significantly higher than soil covered with litter. Soil covered with litter that organic matter, total nitrogen, alkaline nitrogen and available potassium content were significantly higher than soil under lawn.Rainforest, rubber forest, grapefruit forest, theme garden, in these four types of vegetation, soil bulk density, pH, total phosphorus content: theme garden> grapefruit forest> rubber forest> rainforest. Soil organic matters, total nitrogen, alkaline nitrogen content: rainforest> rubber forest> grapefruit forest> theme garden. Total potassium content of the soil:rubber forest> grapefruit forest> rainforest> theme garden. Soil available potassium: grapefruit forest> theme garden> rainforest> rubber forest.There were no obvious differences between soil nutrient in single rubber forest and rubber tea forest.(5) The water content of fresh soil on the southern slope was significant lower than the north slope.