云南省南涧县植烟土壤pH和有效磷的时空变化特征

Spatial-temporal variation of pH and Olsen-P in tobacco growing soil in Nanjian county,Yunnan province

运用地统计学方法系统分析了1982、2012、2018和2022年4个时期云南省大理州典型县域南涧县植烟土壤pH和有效磷时空变异特征及空间分布格局,为该区烟田养分管理及平衡施肥提供科学依据。结果表明,1982—2022年40年间,南涧县植烟土壤p H呈下降趋势,年均下降速率为0.014个单位,4个时期土壤pH均属强空间自相关性;pH处于Ⅲ级烟田面积占比减少,其中东北部和西南部下降明显,Ⅰ和Ⅱ级面积占比增加,但仍以Ⅲ级面积占比最高。40年间土壤有效磷含量先上升再下降,其中1982—2012年为上升期,年均增加速率为0.34 mg/kg;2012—2022年为下降期,年均下降速率为0.76 mg/kg。1982、2018和2022年有效磷属强空间自相关性,结构因素占主导作用,2012年有效磷为中等空间自相关性(44.1%),受结构因素和人为因素的共同影响。1982—2022年有效磷等级面积占比最高由Ⅲ级降至Ⅱ级,含量偏低区域集中在乐秋乡、宝华镇东北部及小湾东镇部分区域。总体而言,40年间南涧县植烟土壤p H呈下降趋势,西部烟田土壤pH整体偏低。有效磷呈先上升后下降的趋势,西部含量偏低,东北部含量偏高。整体上,南涧县应防控植烟土壤酸化,适当提高磷肥施用量,推广有机无机配施的管理措施,提升烟田土壤肥力。

Geostatistical methods were used to systematically analyze the spatio-temporal variation characteristics and spatial distribution patterns of pH and Olsen-P in tobacco growing soil in Nanjian county,a typical county of Dali prefecture,Yunnan province,during 1982,2012,2018 and 2022,which could provide scientific basis for nutrient management and balanced fertilization in tobacco fields in this area.The results showed that the soil pH showed a decreasing trend during the 40 years from 1982 to 2022,with an average annual decrease rate of 0.014 units,and the soil pH was strongly spatially autocorrelated in all four periods.The proportion of pH grade III tobacco field area was decreased,including a significant decrease in the northeast and southwest,and the proportion in grade I and II was increased,but the proportion of grade III area was still the highest.The soil Olsen-P content was increased first and then decreased during the past 40 years,with an average annual increase rate of 0.34 mg/kg during 1982-2012,and the average annual decrease rate was 0.76 mg/kg during 2012-2022.The Olsen-P showed strong spatial autocorrelation in 1982,2018 and 2022,and structural factors played a dominant role,while the Olsen-P showed moderate spatial autocorrelation(44.1%)in 2012,which was affected by both structural factors and human factors.The highest proportion of Olsen-P grade area was decreased from gradeⅢto gradeⅡfrom 1982 to 2022,and the low content areas were concentrated in Leqiu town,the northeast of Baohua town and part area of Xiaowandong town.During the 40 years,the soil pH showed a decreasing trend,and the pH was generally low in the west of the county.The Olsen-P was increased first and then decreased,with a low content in the west and a high content in the northeast.The soil acidification should be prevented and controlled in Nanjian county as a whole,and the application of phosphorus fertilizer should be increased appropriately.The management measures of organic and inorganic combined application should be promoted to improve the soil fertility of tobacco fields.