Positive effects of cement kiln exhausts on legume crops under simulation study

Soil application of cement kiln exhausts (electrostatic precipitator dust) at both lower and higher concentrations did not inhibit growth, nodule formation, and productivity inCajanus cajan, vigna radiata, andVigna mungo. In fact, growth was promoted, possibly because of the dust containing most of the elements, such as N, Ca, Fe, Mg, Mn, K, Zn, P, S, and Cu, which are needed for plant growth and root nodulation. Foliar application of the dust did not affect chlorophylls and carotenoids. The rate of photosynthesis as measured by CO2 uptake and stomatal diffusive resistance of all legumes were not affected. There was a biomagnification of Mg and K in leaves and seeds. Addition of the ESP dust did not affect either the soil or nodule rhizobial population. It is evident that the dust did not act as a phytotoxicant but as an elixir of plant life.