High Aluminium Concentration and Soil Acid Saturation Reduce Germination, Emergence and Seedling Establishment of Groundnut.

Abstract

Studies on crop responses to soil acidity have largely neglected the germination and seedling establishment stages. The objective of this study was to determine the effect of soil acidity, including aluminium per se and acid saturation, on germination, emergence and establishment of groundnut seeds. Germination was carried out on groundnut cultivars Harts, Jasper and Rambo under 0, 50, 100 and 200 μM Al applied as Al2 (SO4)3.18H2O at pH between 4.2 and 4.5. Seedling emergence and establishment were examined in 0, 3 and 6 g of dolomitic lime per kg of soil, representing control, 50% lime requirement and 100% lime requirement, respectively. High Al concentration of 200 μM reduced germination, germination velocity index and seminal root length but had no influence on mean germination time of all groundnut cultivars. There were highly significant differences (P<0.001) in seedling emergence between non-limed and limed soils. Root length and mass were significantly (P<0.05) reduced at high soil acidity but the cultivar Rambo was least susceptible. We conclude that the germination, emergence and establishment stages were negatively affected by high Al levels and acid saturation but the cultivars showed different tolerance levels to high acid saturation, and proper liming can ameliorate the problems associated with these growth stages.