广元植烟土壤有效态微量元素的空间变异特征及影响因素

为揭示广元植烟区土壤有效态微量元素含量空间变异特征及影响因素,采用地统计学、相关分析及回归分析等研究方法,结合地理信息系统(GIS)技术对研究区土壤有效铁、锰、铜、锌钼及硼等6种土壤有效态微量元素进行分析。结果表明,研究区土壤有效铁、锰及铜含量丰富,总体处于中等以上水平;有效钼含量适中;有效锌和硼缺乏,总体处于缺乏或极度缺乏水平。半方差分析表明,6种土壤有效态微量元素块金系数均在29.72%~67.59%之间,具有中等强度的空间自相关性,其空间变异受结构性因素和随机性因素共同影响。空间分布上,土壤有效铁、锰、铜及钼含量表现出北高南低的空间分布趋势,土壤有效锌和硼含量呈现出西高东低的空间分布格局。影响因素分析表明,6种土壤有效态微量元素与土壤有机质呈正相关,与p H值呈负相关,相关性总体高于地形因子。土壤有机质对有效铁、铜、锌及硼有极显著影响,其空间变异性为5.5%~27.2%。除有效锌外,土壤p H值对其余5种土壤有效态微量元素含量空间变异均有极显著影响,其空间变异性为5.0%~30.4%。土类对土壤有效铁、锰及铜有极显著影响,其空间变异性8.4%~12.3%。熟制和种植制度对6种土壤有效态微量元素含量空间变异的影响较弱,进一步说明研究区土壤有效态微量元素含量空间变异受结构性因素和随机性因素共同影响,但结构性因素的作用强于随机性因素。本研究结果为广元植烟区土壤微肥施肥管理及优质烤烟栽培提供了可靠的参考依据。

Spatial Variability of Soil Available Microelement Contents and Their Influencing Factors in Tobacco Growing Area in Guangyuan City

Six soil available microelement contents (available Fe,Mn,Cu,Zn,Mo and B) were analyzed as well as their influencing factors using geostatistics,correction analysis,regression analysis and GIS technology to reveal their spatial variability and influencing factors.The results indicated that soil available Fe,Mn,and Cu were rich in the study area over the medium level on the whole;available Zn and B contents were lacking at a poor level while available Zn content was at the medium level.Semi-variance analysis showed the ratio of nugget to sill of the six soil available microelements ranged from 29.72％ to 67.59％ with a moderate spatial autocorrelation indicating that the spatial variability of the six soil available microelement contents were affected by structural and random factors.For the spatial distribution,soil available Fe,Mn,Cu and Mo contents displayed the similar distribution tendency with a high content in north and low in south and available Zn and B showed a similar distribution tendency with a high content in west and low in east.Influencing factors analysis showed the six microelement contents were positively correlated with soil organic matter and negatively correlated with pH value,and the correlation between soil available microelement contents and main nutrient was higher than terrain factors.Soil organic matter had extremely significant impact on the spatial variability of soil available Fe,Cu,Zn and B,and can explain 5.5％ ～ 27.2％ of the variability for the four soil available microelements.Except available Zn,soil pH value had extremely significant influence on the spatial variability of the other soil available microelements,and the explanatory ability of soil pH value was between 5.0％ and 30.4％.Soil type had extremely significant impact on the spatial variability of available Fe,Mn and Cu,and the explanatory ability of soil type is between 8.4％ and 12.3％.In contrary,cooked and cropping system had weaker effect on the spatial variability of the six soil available microelements than soil organic matter,pH value and soil type,indicating that the spatial variability of soil available microelement contents were affected by structural and random factors while the effect of structural factors played a more important role than random factors in the study area.This result can provide a reasonable reference for soil fertilization management of microelements and high quality tobacco cultivation in Guangyuan tobacco growing area.