Abstract

The effect of seasonal variation on the nutrient and anti-nutrient contents of some selected vegetables cultivated under local agricultural practices by farmers from Wamakko, Sokoto State, were investigated. The concentrations of the elements in their soil were also studied. For the macroelements, significant differences at P<0.05 were observed in tomato for Na and K. In amaranth, it was observed only in Na, Ca and Mg. In roselle, it was observed in Na, K and Ca; while in kenaf, it was observed in all the elements except in P. Significant differences at P<0.05 were observed in all the trace elements except Fe, Mn and Pb in tomato, Cu, Zn and Mn in amaranth, Zn, Mn and Pb in roselle and Zn and Mn in kenaf. In most cases the values for the trace elements except Ni and Pb were higher in the rainy season samples. The soils for rainy season samples indicated higher values for all the macro elements, while an irregular trend was observed for the trace elements. No significant difference was observed for vitamin A, oxalate and nitrate concentrations in the samples. For vitamin C, only amaranth and kenaf indicated significant differences. The effect of seasonal variation on the concentrations of each of the nutrients varies from one vegetable to another.

Key words: Dry and rainy seasons, nutrient, antinutrient, vegetables.