Período crítico de interferência de plantas daninhas na cultura dos citros no município de Manaus

Abstract

The inexistence of work on the critical period of weed interference on citrus cultivation in the State of Amazonas prevents citrus farmers to control infested plants at the most appropriated time and, consequently, to reduce the production costs of a citrus orchard (Citrus sinensis (L.) Osbeck). Accordingly, this study aimed to determine the critical period of weed interference on citrus plants. The experiment was conducted with Pear orange orchard with age ranging from 4 to 20 years on the farm Brejo do Matao located at km 15 of highway BR 174, near Manaus, AM. The experimental lineation was randomized in blocks with four repetitions. The treatments were defined based on normal rainfall for the city of Manaus and periods of interference or not of the weed plants with the orange trees. The parameters evaluated were as follows: (i) fruit weight, (ii) juice volume, (iii) orange juice yield, (iv) fruit production and (v) identification and (vi) dry weight of weed plants. The periods of weed control did not influence the physical qualities of the orange as weight, volume and yield. The yield per hectare was higher than other treatments when weed was controlled in the period from October to May and from February to May. The species of weed that stood out quantitatively were Commelina diffusa Burm. f., Homolepis aturensis (Kunth) Chase, Croton lobatus L., Cleomes affinis DC. e Paspalum conjugatum Berg. The critical period of weed interference with the orange trees was from February to May. The periods with and without interference were not significant for the physical qualities of the Pear orange fruit under the conditions studied