Influence of copper oxide and zinc oxide nano-particles on growth of fodder cowpea and soil microbiological properties

Abstract

A study was conducted in net house to record the effects of seed treatment with varying levels of nano copper oxide (nCuO; 25, 50, 100 and 200 ppm) and nano zinc oxide (nZnO; 250, 500 and 750 ppm) on the growth of cowpea and bioaccumulation of minerals in plants under pot culture condition. It was found that 25 ppm of nCuO enhanced germination percentage, while seedling length and biomass were maximum at 50 ppm compared to control and RDF CuSO4 (@20 kg/ha) treatment. Concentration of nCuO at 100 ppm recorded maximum shoot length (77.3 cm), however, 50 ppm of nCuO had significantly higher root length (20.4 cm) and nodulation in cowpea. It was found that the availability of Cu in plant system was enhanced with increase in concentration of nCuO up to 100 ppm (17.8 µg/g). Highest availability of Zn (45.4 µg/g) in plant dry matter was recorded at 25 ppm of nCuO. The influence of nCuO particles on the soil microbiological properties was also studied, and it was found that there was no significant difference between control and nCuO treatments up to 100 ppm in terms of both dehydrogenase activity and total bacterial count (TBC). However, decrease in dehydrogenase activity and TBC was observed at 200 ppm. Soil microbial biomass carbon (SMBC) was maximum at 50 ppm of nCuO. I n nZnO treatments (up to 750 ppm), all microbiological parameters studied were higher when compared to control.