Foliar application of molybdenum on cover crops and response of common beans in successive cultivation

Abstract

The effects of foliar application of Mo and use of N from cover crops (Crotalaria juncea L. and Canavalia ensiformis (L.) DC) on the performance of common beans were investigated in this study. Field experiments were carried out in a succession planting system (cover crops – common beans), and nitrate reductase activities were evaluated in the laboratory. For the production of cover crops, a 2 x 4 factorial scheme was installed, with the two cover crops sunn hemp and jack bean, along with four doses of Mo (0, 40, 80, and 120 g ha-1) in the form of sodium molybdate (Na2MoO4 ) through foliar application in random blocks with four replications. For bean cultivation, an unfertilized control treatment was evaluated. Sunn hemp showed a linear positive response to Mo application in terms of shoot dry matter and N accumulation, while jack bean showed a quadratic negative response for shoot dry matter; for N accumulation, there was no adjustment of the regression models. Nitrate reductase activity in the common beans was up to three times higher at the Mo dose of 0 g ha-1 when compared to the treatments with Mo application to both cover crops. Cover crops or Mo doses had no significant effect on bean productivity.