1. Soil fertility management research for the maize cropping systems of smallholders in southern africa: A review;Kumwenda,1996
2. Response of five maize genotypes to nitrogen, phosphorus and lime on acid soils of western kenya;Gudu;Afr. Crop Sci.,2005
3. Physiological effects of hydrogen, aluminum and manganese toxicities in acid soils;Foy,1984
4. Aluminum toxicity in crop plants