Acidic Soils in Kenya: Constraints and Remedial Options

Abstract

Acidic soils can be identified when a soil sample is analysed in any soil laboratory. In soil laboratories within the Kenya Agricultural Research Institute (KARI), acidic soils are classified further according to severity of acidity (Table 1). Crop tolerance to acidity Different crops have various degrees of tolerance to acidity. Chillies, sweetpotatoes and irish potatoes are tolerant to acidity and can do well in soils with pH values below 5.5 (Plates 1 and 2). Most of the horticultural crops (onions, spinach, carrots, cabbages and cauliflower) do not tolerate acidity and can only grow well in soils with pH values above 6.0. Other crops like maize lie in the medium tolerance range and would do well in 5.5-6.0 pH values. Among the maize varieties, local cultivars like Githigu commonly found in central Kenya are adapted to the lower end of the tolerance range. Most of the flowers grown for export are sensitive to acidity. When crops are grown in soils with pH values below the lower limit, they give low yields and are of poor