2019 年 63 巻 2 号 p. 94-101
Soil information is key to determine optimum agricultural management. Especially, the understanding of inherent soil characteristics combined with appropriate soil fertility evaluation are necessary. In many countries, soil information is outdated and no reliable information exists. We focused our effort in the central highlands of Malawi, the major potato (Solanum tuberosum L.) producing area where the current yield is low. This study was conducted to classify and evaluate agricultural soils in the area. Three soil profiles were evaluated in the area. Bembeke Agricultural Experimental Station and Chimlambe village soils were classified into Oxisols while Sithawika village soil was classified into Entisols. Kaolinite dominated in Oxisols whereas in Entisols, kaolinite and illite co-dominated. In this area, topography was a major soil forming factor, influencing the supply of colluvial and alluvial materials. Total C contents as well as CEC were variable among the sites and reflected soil moisture regimes, topography, and intensity of agricultural management. The nutrient results indicated low base cation contents in Oxisols unlike the previous reports, while P contents were not low. In conclusion, two different soil orders exist in the study area with variable clay mineralogy and total C contents while nutrient imbalance was observed reflecting the interaction of inherent soil characteristics and agricultural management.
