海南省果园土壤肥力综合评价研究

Comprehensive Evaluation of Soil Fertility in Orchards of Hainan Province

针对目前海南省果园土壤养分肥力情况尚不明确的问题,对海南省果园土壤肥力状况进行调研并取样分析,旨在为指导海南果园合理施肥提供科学依据。采用“S”型采样法采集海南省果园土壤样品271个,分析土壤肥力指标,其中包括有机质、全氮、有效磷、速效钾、阳离子交换量和pH,依据全国第二次土壤普查的土壤养分分级指标来评价单个肥力指标,采用相关性系数法确定各指标的权重,并采用模糊数学隶属度函数对海南果园土壤肥力状况进行了综合评价,分析了影响土壤肥力的因素。结果表明:海南省果园土壤pH、阳离子交换量、有机质、全氮和速效钾的平均值分别为5.4 cmol/kg、8.56 cmol/kg、13.4 g/kg、0.68 g/kg、62.5 mg/kg和109 mg/kg,研究区土壤酸化严重,土壤保水保肥能力弱,有机质和全氮含量处于缺乏水平,速效钾含量处于中等偏低水平,有效磷含量处于丰富水平,但其空间变异性较大;各市县土壤综合肥力指数IFI依次为海口(0.64,2级)>临高(0.62,2级)>琼中(0.48,3级)>澄迈(0.45,3级)>琼海(0.44,3级)>三亚(0.43,3级)>白沙(0.42,3级)=屯昌(0.42,3级)>儋州(0.36,4级)>东方(0.35,4级)>保亭(0.32,4级)>昌江(0.29,4级)=乐东(0.29,4级)>陵水(0.25,4级)>万宁(0.20,4级)>定安(0.19,5级)=文昌(0.19,5级),其中海口和临高的肥力状况处于中上水平;全省土壤综合肥力指数IFI变幅范围是0.13~0.95,平均值为0.37,土壤肥力等级为4级,仅13.3%的样本综合肥力处于丰富及以上水平。因此,海南省果园土壤综合肥力处于较低水平,土壤中有机质、全氮、速效钾和阳离子交换量对海南果园土壤肥力水平影响较大。海南果园应在原有管理措施下注重有机肥的施用,并根据不同区域的具体养分匮乏状况适当调整氮、磷、钾肥施入量比例,同时应当加强果园土壤酸化调控,以防止果园土壤继续酸化,实现海南果业长期可持续发展。

The soil fertility status was investigated and analyzed to provide scientific basis for guiding the rational fer-tilization of the orchards in Hainan,due to the unclear soil nutrient fertility status.In this study,271 soil samples from the orchards in Hainan were collected by the S-type sampling method,and the soil fertility indicators were analyzed,including organic matter,total nitrogen,available phosphorus,available potassium,cation exchange capacity,and pH.The single fertility index was evaluated using the soil nutrient classification standard issued by the second national soil survey.The correlation coefficient method was applied to determine the weight of each indicator.The fuzzy mathemat-ics membership function was used to comprehensively evaluate the soil fertility of the study area.Moreover,the factors which affected the soil fertility were analyzed.The results showed that the average values of pH,cation exchange ca-pacity,organic matter,total nitrogen,available phosphorus,and available potassium was 5.4 cmol/kg,8.56 cmol/kg,13.4 g/kg,0.68 g/kg,62.5 mg/kg,and 109 mg/kg,respectively,which suggested that the soil acidification in the study area was serious,the ability of preservation moisture and fertility was weak,both organic matter and total nitrogen con-tent were in the deficient level,the content of available potassium was at medium to low level,and the content of available phosphorus was at the rich level with great spatial variability.IFI ranking of cities(counties)in Hainan was Haikou(0.64,Level 2)>Lingao(0.62,Level 2)>Qiongzhong(0.48,Level 3)>Chengmai(0.45,Level 3)>Qionghai(0.44,Level 3)>Sanya(0.43,Level 3)>Baisha(0.42,Level 3)=Tunchang(0.42,Level 3)>Danzhou(0.36,Level 4)>Dongfang(0.35,Level 4)>Baoting(0.32,Level 4)>Changjiang(0.29,Level 4)=Ledong(0.29,Level 4)>Lingshui(0.25,Level 4)>Wanning(0.20,Level 4)>Dingan(0.19,Level 5)=Wenchang(0.19,Level 5),only the soil fertility of Haikou and Lingao was at high level.The IFI of soil comprehensive fertility index was ranged from 0.13 to 0.95 with an average value of 0.37,and only 13.3%of the samples was at rich fertility level.Therefore,the soil of the study area was at a low fertility level,the fertility quality was influenced by the contents of OM,TN,AK,and CEC in soil.Under the existing management measures,the application of organic fertilizer should be emphasized,and the proportion of nitro-gen,phosphorus and potash fertilizer should be appropriately adjusted according to the specific nutrient deficiency in different regions.Meanwhile,the amelioration of soil acidity should be emphasized to avoid further soil acidification to achieve the sustainable development of Hainan fruit industry.