云南大理烟区土壤有效磷时空变化及分区施磷策略

The spatiotemporal variation of soil available phosphorus and phosphorus application strategy in tobacco field of Dali,Yunnan Province

【目的】研究云南大理烟区土壤有效磷的时空变异特征及分区,为优质烟草生产中磷素管理和面源污染控制提供科学依据。【方法】试验在云南大理开展,该区年均烤烟种植面积3.23万hm^(2)左右,分别于1999、2012、2018和2022年选取5个典型植烟片区的代表性烟田256、633、1244和2332块,测定土壤有效磷含量,利用地统计学及GIS技术分析近40年5个时间段(1982、1999、2012、2018和2022年)大理5个植烟县域土壤有效磷时空变异特征,依据土壤有效磷含量现状进行合理施磷分区。【结果】烟区土壤有效磷含量呈逐渐升高趋势,1982—2022年有效磷含量由8.09 mg/kg升高到43.92 mg/kg,升高了4.42倍。1982年有效磷含量均处“低”等级(<20 mg/kg),1999—2022年以“中等”为主(20~40 mg/kg),面积占比50%以上。近40年土壤有效磷块金效应由<25%上升至41.45%,表明地形等自然因素影响减弱,施肥等人为因素影响增强。根据当前有效磷含量,高磷区和极高磷区面积占比34.21%,主要分布于弥渡北部、祥云西部及宾川西南和东北。【结论】近40年大理烟区土壤有效磷提升明显,人为因素作用增强,总体有效磷含量较高,大部分烟田可减施或不施磷肥,应分区施磷。

【Objectives】This study investigated the spatiotemporal variation of soil available phosphorus(AP)in tobacco-growing areas of Dali Prefecture,Yunnan Province,aimed to provide a scientific basis for phosphorus management friendly to high-quality tobacco production and sustainable environment.【Methods】The total tobacco planting area in Dali Prefecture is around 3.23×10^(4) hm^(2).256,633,1244 and 2332 soil samples were collected from the five typical tobacco planting counties of Dali in 1999,2012,2018 and 2022 respectively,for determination of soil AP content.Geostatistics and GIS technology were used to analyze the spatiotemporal variation of soil AP in the five counties over the four decades.Finally,a general phosphorus application strategy was proposed based on the soil AP content in 2022.【Results】The average soil AP content in the tobaccogrowing areas of Dali trended to increase over the last 40 years.The average soil AP increased from 8.09 mg/kg in with an increase of 4.42 times.The soil AP content in most tobacco planting area belonged to‘low’grade(<20 mg/kg)in 1982,and over 50% of soil belonged to‘medium’grade(20-40 mg/kg)in 1999-2022.The nugget effect of soil AP increased from less than 25% to 41.45% over the last 40 years,indicating a weakening influence of natural factors such as topography and an increasing impact of human factors such as fertilization.In 2022,34.21%of the total area were high and even extremely high in soil AP,mainly distributed in the north of Midu,west of Xiangyun,southwest and northeast of Binchuan.【Conclusions】The soil AP content in Dali tobacco-growing areas has significantly increased on average over the past four decades due to fertilization.Most tobacco fields should reduce or even stop phosphorous fertilizer application.