重庆渝东北植烟区土壤交换性钙镁与土壤属性的关联特性研究

为明确重庆渝东北植烟区土壤中交换性钙、镁养分状况与土壤属性的关联特性，为烟区养分管理提供参考依据，利用GPS定位技术在渝东北植烟区采集了1 092个代表性土壤样品，对巫溪、巫山、奉节、万州、涪陵和丰都6个区县植烟土壤交换性钙和交换性镁含量分析，同时与其他土壤属性进行关联分析。结果表明：重庆渝东北植烟土壤交换性钙、镁含量丰富，其平均值分别为10.85 cmol/kg和1.79 cmol/kg，但也存在缺乏现象，且区域分布不均衡。总体来看，土壤交换性钙缺乏(<6 cmol/kg)占比28.30%，土壤交换性镁缺乏(<1.0 cmol/kg)占比42.75%。涪陵县与丰都县的土壤交换性钙、镁缺乏最严重，占比分别为40.00%和55.00%。丰都县与万州区土壤交换性钙、镁含量最适宜烤烟种植，占比分别为42.00%和36.61%。母质是影响土壤交换性钙、镁含量的重要因素，二叠系泥灰岩发育形成的土壤交换性钙、镁含量较高，侏罗纪紫色砂岩含量最低。植烟土壤pH、阳离子交换量与交换性钙、镁存在显著正相关关系，而土壤交换性酸总量与二者呈显著负相关，交换性钙镁缺乏是引起烟田酸化的主要原因。1～2...

Association Between Exchangeable Calcium (Ca2+) and Magnesium (Mg2+) with Other Soil Properties in Tobacco Planting Area of Northeast Chongqing

The purpose of this paper is to clarify the correlation between exchangeable calcium and magnesium nutrient status and soil properties in soils of the northeastern Chongqing tobacco-growing region and to provide a reference basis for nutrient management. Using GPS positioning technology, 1092 representative soil samples from Wuxi, Wushan, Fengjie, Wanzhou, Fuling and Fengdu were collected and the exchangeable calcium and magnesium contents were analysed and correlated with other soil properties. The results showed that the average values of exchangeable calcium and magnesium in soils planted with tobacco in northeast Chongqing were 10.85 cmol/kg and 1.79 cmol/kg, respectively, but there were also deficiencies and uneven regional distribution. Overall, 28.30% of the soils were deficient in exchangeable calcium (<6 cmol/kg) and 42.75% in exchangeable magnesium (<1.0 cmol/kg). Soil exchange calcium and magnesium deficiencies were most severe in Fuling and Fengdu counties, accounting for 40.00% and 55.00%, respectively. Fengdu County and Wanzhou District had the most suitable soil exchangeable calcium and magnesium content for roasted tobacco cultivation, with 42.00% and 36.61%, respectively. The parent material is an important factor influencing the soil exchangeable calcium and magnesium content, which are high in Permian marl development forms soils, low in Jurassic purple sandstone development forms soils. Soil pH, cation exchange and exchangeable calcium and magnesium were significantly positively correlated, whereas total soil exchangeable acid was significantly negatively correlated with both, so lack of exchangeable calcium and magnesium was the main cause of acidification in tobacco fields. 1 ~ 2 mm and <0.25 mm size agglomerates were the key factors causing soil exchangeable calcium and magnesium differentiation, and the formation of large agglomerates in soils >2 mm in size should be promoted. This study can provide a scientific basis for the management of soil exchangeable calcium and magnesium nutrients in tobacco planted in the northeastern part of Chongqing.