The evolution and evaluation of orchard soil fertility in red earth regions of Guangxi

The characteristics of soil fertility evolution for various fruits age and change of orchard soil fertility in red earth regions of Guangxi province were evaluated by mathematical statistic software—SPSS. Results showed that the Integrated Fertility Index (IFI) of orchard soil in red earth regions of Guangxi were between 0.17 to 0.25 and belong to mid-low level. The changes of IFI in various fruits age was trending to the shape of "N". The IFI of orchard soil rose slightly in the first 10 years, then declined gradually, and increased again over 30 years. The factors that lead to charges of IFI in orchard soil were mainly: effects of climate of high temperature and rainfall, environment of orchard and input fertilizer together. Last 15 years, the orchards of 11—15 years, the soil sand contents of orchard increased by 23% than that orchards planting for 0—5 years, and large aggregates (>1mm) and ECEC decreased by 24% and 3.0 cmol/kg, respectively, due to serious soil erosion and soil sandification. It's a task of top priority in fruit production of Guangxi to prevent new planting orchard soil erosion and deterioration of soil environment.