Efeito de diferentes doses e volumes de calda do herbicida aclonifena no controlo em pré-emergência de infestantes na cultura do grão-de-bico

Abstract

During a two year period (2015/2016 and 2016/2017) two field trials were carried out on the Experimental farms of Almocreva (Beja) and Passinho (Elvas) respectively. The aim of these trials was to study the effect of a pre-emergence herbicide aclonifen (60%) applied in different doses in interaction with two water volumes, in the weed control and grain yield of chickpea (Cicer arietinum L.) crop. The herbicide doses studied were 1500, 1800, 2100 and 2400 g a.i. ha-1, corresponding the lower dose to the minimum recommended by the herbicide manufacturer for this crop, and the highest dose, to the maximum recommended. The water volumes were 300 and 400 L ha-1with the recommended application volume varying between 300 and 500 L ha-1. Both, doses and spray volumes used are recommended in Spain, being this herbicide in the final phase of approval for Portugal. There was a higher reinfestation at the second year of the trials, but the interaction year x dose x volume was not significant in relation to the grain yield per unit of area, with significant differences in this parameter, only to herbicide doses and to the interaction year x dose. The correlation between the efficacy of the herbicide and grain yield was highly significant for the two experimental years and different modalities (dose x volume). For each year, there was a significant correlation between seed yield per unit of area and number of pod per plant, plant height and number of seeds per unit of area. The opposite was registered regarding the number of plants per unit area and mean seed weight.