Effects of soil type on the emergence, flowering, nutrient uptake and yield components of bambara groundnut (Vigna subterranea (L.) Verde) landraces in Botswana

Abstract

On-station experiments were conducted at the Regional Agricultural Research Station-Impala in Francistown. Botswana, during 2003/04, 2004/05 and 2005/06 seasons to determine the effects of sandy loam and sandy clay loam soil types on the emergence, flowering, nutrient uptake and yield components of two bambara groundnut (E/g/ur subterrunea (L.) Verde) landraces. The two soil types were about 50 m apart within the same Held. Within each soil type, two landraces were each planted in four 3.75m by 5 m replicate plots al 75cm inter­ rows by 20cm within rows and the experimental design was a randomized complete block. Planting bambara groundnut in sandy loam soil (SL) resulted in significantly earlier and higher percentage of seedling emergence and flowering, plant stand after emergence, total dry matter, pod number per plant, unshelled pod dry' weight, grain yield, crop residue and soil nutrient uptake than in sandy clay loam soil (SCL). It is concluded that sandy loam soil is a more suitable soil for bambara groundnut production than sandy clay loam soil but might require greater management on soil nutrients as the soil is depleted of soil nutrients more than the sandy clay loam. Also, more studies arc needed to establish the causal factors in the two soil types which bring about the different responses in bambara groundnut.