Soil Nutrient Characteristics And Evaluation Of Holocene-basalt Platform In Jingbo Lake Area

Soil nutrient is the basic composition of soil fertility. Different soil type contains different soil nutrient content under the influence of natural and human factors. Soil nutrient content has obvious spatio-temporal distribution characteristics, and the spatio-temporal distribution characteristics have influence on regional vegetation distribution. The soil properties of Holocene-basalt platform, which is a kind of early soil developed in late volcanic lavas, will have corresponding change with topographic position, lava occurrence and vegetation types.The study of soil nutrient characteristics is a part of soil research of lava plateau. In this paper the evaluation indecis of soil organic matter(SOM),total nitrogen(TN),available nitrogen(AN),total phosphorus(TP),available phosphorus(AN),and available potassium(AK) were selected to research lava plateau soil nutrient properties using single factor analysis and principal component analysis by field investigation and laboratory analysis. Based on the concrete analysis of soil nutrient of Holocene-volcanic lava plateau in Jingbo lake area, the relationship between lava plateau soil nutrient and geographic environmental elements surrounding it was obtained by statistics basic principles.There are six parts in this paper. The first part is introduction, which introduced the main research contents and methods at home and abroad recapitulatively, and the meaning of this paper was presented. The situation of the study area was introduced in the second part, and the nature characteristics and present situation of economic & society development of Holocene volcanic lava plateau in Jingbo lake area were presented briefly . The selection basis of experimental area and main research methods were explained in the third part. Soil nutrient of basalt platform was analyzed and evaluated using statistical methods in the forth part. The analysis of geographic formation of soil nutrient spatial difference of basalt plateau was made in the fifth part. Conclusion and discussion was stated in the sixth part.The statistical analysis showed that, the contents of soil organic matter,total nitrogen,available nitrogen and available potassium were very rich which belonging to the first class level, and the soil total phosphorus and available phosphorus were relatively less. The relationships between soil nutrient and soil organic matter,total nitrogen,available nitrogen,total phosphorus and pH value of sample plots were higher positive correlation, and that between soil nutrient and available potassium was positive correlation, and that between soil nutrient and available phosphorus was higher negative correlation(r=-0.910).Whether analysis from soil nutrient single index(organic matter,total nitrogen,available nitrogen and total phosphorus) or soil principal component scores, soil nutrient of lava plateau showed basalt sediment parent material>alluvium parent material>residual deposit and talus material parent material>volcanic ash parent material. The chronological sequence of these plant communities were mosses and lichens community, short grass community, high grass community, undesirable tree community and shrub community. The soil nutrient was along the succession sequence of plant communities in Jingbo lake area.Higher soil nutrient scores were inclined to occur in the middle part of low and flat lava plateau near to piedmont. The biomass production of platform marginal was low, but local nutrient enrichment was occurred in the relative lower microtopography. The soil nutrient score of the upper part of volcanic cone was higher than that of the middle of volcanic cone.The effect of human activities on different soil nutrient factors was very obvious. The main nutrient factors ,soil organic matter, soil total nitrogen and soil available nitrogen, of grazing area and paddy field area were all increased. But the soil organic matter, soil total nitrogen, soil available nitrogen and soil available potassium of core field were decreased than the average values of these in research area, and soil available phosphorus was increased only. The soil nutrient principal composition scores showed that grazing area >paddy field area>natural soil>core feld.