Seed quality of soya bean based on mineral composition of seeds of 45 varieties grown in a Brazilian Savanna acid soil

Abstract

The Brazilian Savannas (Cerrados), a vast area covering one fourth of the country's territory, has acidic soils that are devoid of nutrients and must be amended before cultivation. Mineral disorder on the soya bean crop has been frequent, mainly due to unbalanced liming and fertilization. There is no information on varietal differences and the impact of these practices on the seed quality. Chemical analyses were performed to assess the levels of elements in seed samples of 45 soya bean varieties from an experiment in a partly- and fully-limed acid soil. The levels of phosphorus, potassium, iron, aluminium, manganese, zinc and copper were inversely proportional to the level of liming. Calcium, magnesium, sodium, molybdenum and titanium did not show statistical differences for seed accumulation in the liming levels. There was a high frequency of varieties derived from Al-intolerant parents to increased levels of P, K, Ca and Mg, contrasting with respective lower levels in the leaves. The varietal differences suggest further investigation on the genetics of mineral element accumulation in the soya bean seeds. Aluminium levels varied between 8.7 to 5.5 mg/kg, respectively, for the partly- and the fully-limed soil, indicating that cultivation of soya beans in these acid soils produced little effect on the quality of seeds.