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以重庆市丰都县植烟区石灰岩土壤为研究对象,通过野外调查采样和室内分析方法,并采用主成分分析法和模糊数学隶属度函数模型估算出土壤适宜性指数(SFI),进而对土壤养分状况进行综合评价。结果表明:(1)该岩溶区植烟土壤pH多呈弱酸性至中性,有23.08%的土壤样品pH低于5.00,这些土壤酸化问题较为突出;(2)有机质和氮含量丰富,78.85%的土样有机质含量处在植烟所需的最适宜范围(15~30 g/kg)内,全部土样的碱解氯含量均在植烟所需的适宜范围(65~100 mg/kg)内,且变异系数仅为0.92%;(3)土壤全磷表现出中至高含量水平(>0.6 g/kg),但土壤有效磷供应不足,20.93%土样有效磷含量处在缺乏水平(<10 mg/kg)以下;(4)土壤钾元素供应充足,全钾含量全部处于丰富或极丰富水平(>25 g/kg),超过81.84%土样其速效钾含量处于植烟所需的适宜范围(>150mg/kg)内;(5)该岩溶区土壤肥力整体水平不高,仅15.38%土样的综合肥力为较高水平(0.70>SFI≥0.60),57.69%为中低等水平(0.60>SFI≥0.40),26.93%为低水平(SFI≤0.40),这与岩溶地区土壤贫瘠且侵蚀退化严重、施肥不合理等因素有关。为此,建议科学耕作,抑制土壤侵蚀退化,同时通过撒施生石灰等调节土壤pH,并适当提高复合肥中磷素比例。
Taking limestone soil in Fengdu County of Chongqing Municipality as the research object, the soil suitability index (SFI) was estimated by field investigation and sampling and indoor analysis, using principal component analysis and fuzzy mathematical membership function, Nutrient status of a comprehensive evaluation. The results showed as follows: (1) pH value of tobacco soil in the karst area was mostly weakly acidic to neutral with 23.08% soil pH lower than 5.00, and the acidification problems of these soils were prominent. (2) The organic matter and nitrogen contents were rich, 78.85% (15-30 g / kg) of the soil organic matter content of all the soil samples were in the appropriate range (65-100 mg / kg) for tobacco planting, , And the coefficient of variation was only 0.92%. (3) The soil total phosphorus showed medium to high levels (> 0.6 g / kg), but the supply of soil available phosphorus was insufficient, and available phosphorus was 20.93% 10 mg / kg). (4) The potassium supply in the soil was sufficient and the total potassium content was all rich or extremely rich (> 25 g / kg). When the available potassium content exceeded 81.84% (5) The overall soil fertility in this karst area was not high. Only 15.38% of the soil samples had higher comprehensive fertility (0.70> SFI≥0.60) and 57.69% 0.60> SFI≥0.40) and low level (SFI≤0.40) of 26.93%, which is related to the poor soils of the karst areas and the serious degradation and erosion of karst areas and unreasonable fertilization. To this end, it is recommended that scientific farming, inhibition of soil erosion degradation, at the same time through the implementation of quicklime and other soil pH adjustment, and appropriate increase in the proportion of phosphorus fertilizer.