Residual effect of a few herbicides on chlorophyll content and primary productivity of succeeding crops and associated weeds

Abstract

The residual effect of a few herbicides viz: Atrataf (atrazine), 2,4-D and Aresin (monolinuron) sprayed in the previous season on the pigment concentration and primary productivity of the crops (viz: Zea mays and Cajanus cajan) grown in rotation, as well as their associated weeds has been studied. The results indicate that the residues of all the three herbicides were non toxic to Zea mays and toxic to Cajanus cajan as an increase in chlorophyll content and primary productivity occurred in the former, whereas the contrary is true for the latter. Weeds from residual plots have shown a considerable decrease in the chlorophyll content and primary productivity. The most susceptible weed to all the three herbicides was Acalypha malabarica, while Echinochloa colonum is susceptible to the residues of Atrazine but is tolerant to the residues of the other two herbicides. Recommendations based on the observations are presented in the paper.