Abstract:

Soil mineral nutrients are important indices for evaluating soil fertility, and are essential nutrient elements for the soil to supply crops. To reduce fertilizer amount and increase efficiency, rational fertilization of crops and improving soil quality of cultivated land, mineral nutrients in cultivated land soil of the main crops in Jiangmen City were investigated and analyzed. The results showed that the average pH of the cultivated soil in Jiangmen was 5.60 and more than 45% of the cultivated soil was acidified. Soil acidity in eggplant and melon vegetable fields, orchards, and paddy fields was stronger. The soil pH in Enping City and Pengjiang/Jianghai was significantly higher than that in other districts. The average soil organic matter content was 26.4 g∙kg⁻¹, with the highest values in Xinhui District and orchard soil, and the lowest in Enping City. The average values of alkali-hydrolytic nitrogen and available potassium content were 120 mg∙kg⁻¹ and 136 mg∙kg⁻¹, respectively, with the highest values in the Xinhui District, Pengjiang/Jianghai District, and orchard soils, and the lowest in Enping City. The available phosphorus content in 74.5% of the soil samples was very high, with an average value of 123 mg∙kg⁻¹.The mean values of exchangeable calcium, exchangeable magnesium, available boron and available silicon in soils were 2.02 cmol∙kg⁻¹, 0.650 cmol∙kg⁻¹, 0.650 mg∙kg⁻¹ and 132 mg∙kg⁻¹, respectively, with slightly higher contents only in Xinhui District, Pengjiang/Jianghai District and orchard. The variability of pH value was weak; organic matter, alkali-hydrolyzed nitrogen, available boron, and available silicon content were moderate; and available phosphorus, available potassium, exchangeable calcium, and exchangeable magnesium content were strong in the soil of different crops and districts, with coefficients of variation ranging from 9.43% to 17.0%, 20.4% to 86.6%, and 55.4% to 143%, respectively. Compared with the results of the second soil survey, the cultivated soil in Jiangmen showed increased acidification, significantly increased available phosphorus content, and slightly increased organic matter, alkali-hydrolyzed nitrogen, and available potassium content. In Jiangmen, the contents of organic matter and alkali-hydrolyzed nitrogen were medium-high, the contents of available potassium, available boron, and available silicon were low, and the contents of exchangeable calcium and exchangeable magnesium were lacking. Therefore, the differences in mineral nutrients in the Jiangmen area are evident, and the differences in soil mineral nutrients in different crops and regions cannot be ignored. It is necessary for Jiangmen City to promote soil testing formula and precise balanced fertilization according to the overall principle of “controlling nitrogen, reducing phosphorus, improving organic matter, increasing potassium, stabilizing borosilicate, and supplementing calcium and magnesium”.

Key words: Jiangmen City, cultivated land, soil, mineral nutrients, variability

摘要：

土壤矿质养分是评价土壤肥力的重要指标，是土壤供给作物生长的必需营养元素。为实现化肥减量增效、农作物合理施肥及耕地土壤质量提升目标，对江门市主要作物的耕地土壤进行矿质养分调查分析。结果表明，江门市耕地土壤pH均值5.60，超过45%的耕地土壤酸化严重，茄果与瓜类蔬菜地、果园及稻田土壤酸性较强，恩平市及蓬江/江海地区土壤pH明显高于其他县区。土壤有机质平均质量分数为26.4 g∙kg⁻¹，以新会区及果园土壤最高，恩平市最低。碱解氮和速效钾均值分别为120 mg∙kg⁻¹和136 mg∙kg⁻¹，新会区、蓬江/江海区及果园土壤最高，恩平市最低。74.5%样点的土壤有效磷含量达到极丰富水平，均值为123 mg∙kg⁻¹。土壤交换性钙、交换性镁质量摩尔浓度与有效硼、有效硅质量分数均值分别为2.02 cmol∙kg⁻¹、0.650 cmol∙kg⁻¹、0.650 mg∙kg⁻¹和132 mg∙kg⁻¹，仅新会区、蓬江/江海区及果园土壤含量稍高。不同作物及县区间的土壤pH变异性较弱，变异系数为9.43%—17.0%，有机质、碱解氮、有效硼和有效硅含量变异性中等，变异系数为20.4%—86.6%，有效磷、速效钾、交换性钙和交换性镁含量变异性较强，变异系数为55.4%—143%。与第二次土壤普查结果相比，江门市耕地土壤具有酸化加剧的趋势，有效磷含量极显著提升，有机质、碱解氮和速效钾含量有所提升。江门市耕地土壤有机质和碱解氮含量中等偏高水平，速效钾，有效硼和有效硅含量偏低，交换性钙和交换性镁缺乏。江门地区整体土壤矿质养分差异明显，不同作物及区域间土壤矿质养分差异不可忽视，需按照“控氮、减磷、提质、增钾、稳硼硅、补钙镁”的总体原则，推广测土配方及精准平衡施肥。

关键词: 江门市, 耕地, 土壤, 矿质养分, 变异性