Soil nutrient evaluation of pitaya orchards based on factor and cluster analysis
In order to investigate the current soil nutrient status of pitaya orchards in Hainan Province,184 soil samples were collected and analyzed by using 6 soil nutrient indices.Their nutrient indices were graded each and then comprehensively evaluated based on factor and cluster analyses.The results showed that soil acidification was evident in most of the pitaya fields under survey,with 72.82％of the pitaya fields at pH＜4.5 and pH 5.0-6.5.The soil ammonium nitrogen content was generally low,less than 0.01 mg/kg in 100％of the total pitaya fields.The contents of available potassium,total nitrogen and organic carbon were low in some fields,23.37％,23.37％and 33.7％,respectively,which were at the low or below levels.The soil available phosphorus content was the highest,and the proportion of plots in medium grade and above accounted for 100％.Factor analysis showed that two common factors could be extracted from the six nutrient indexes measured,among which total nitrogen,organic carbon,available potassium,ammonium nitrogen and pH were listed in factors 1 and 2 that mainly affected the comprehensive soil nutrient status of pitaya orchards.Cluster analysis of the soil nutrient comprehensive index IFI showed that the soil IFI values of the pitaya orchards in Hainan Province ranged from-0.904 to 1.405 with an average value being-0.171,of which only 41.3％of the soil was at medium or above fertility levels.In Ledong,Dongfang,Sanya and Lingshui which were pitaya major producers,the soil IFI values were at low fertility level in 80.33％and 50％of the pitaya orchards in Dongfang and Lingshui,respectively.In Sanya,the soil IFI values were above medium fertility level in 61.9％of the pitaya orchards.Overall,the soil fertility status in most areas of the pitaya orchards in Hainan Province(except Sanya)was below the medium level.
万方数据
维普
