Effect of Nitrogen Nutritional Stress on Some Growth Parameters

This study investigated the responses of maize (Zea mays L.) and cowpea (Vigna unguiculata L. Walp.) seedlings growth parameters to nitrogen nutritional stress. This was with a view to determining whether nitrogen nutritional stress would retard or enhance maize and cowpea growth, partly, wholly or not at all through its effect on biomass accumulation and some morphological parameters. Germination of seeds was done using treated sand in sixty plastic pots. A group of the seedlings was nutrient stressed by administering 200 ml of complete nutrient solution minus nitrogen (-N) while the other groups were fed with five times (X5N) and ten times (X10N) the optimal concentration of nitrogen and the last regime was fed with full nutrient solution (FN). The effects of optimal concentration and nitrogen stress on the growth rates (as measured by their fresh and dry weight) were studied. The result of the growth analysis showed that there was increase in shoot height with supraoptimal concentrations of nitrogen treatments (X10N and X5N) while there was a decrease in shoot height with minus nitrogen (-N) regimes. The observed higher biomass (dry matter yield) under the FN regimes in both Zea mays and Vigna unguiculata were attributed to optimal nutrient assimilation rate