Sorção do Diuron e Sulfentrazone em diferentes tipos de materiais, usados como substrato, para produção de mudas de citros no estado do amazonas

Abstract

The citrus cultivation is very important for the state of Amazonas and can generate jobs and foreign exchange for the state. In this state, weed management has been one of the main factors that increases the production cost of the crop. Currently, the use of chemical control by the application of herbicides has been the most used in the control of weeds, however despite the advantages of this method, it is necessary to know the interactions of these herbicides with the properties of the soil. In the production of citrus seedlings the substrate is one of the important inputs for the production of healthy and vigorous seedlings. This work aimed to quantify the sorption of diuron and sulfentrazone herbicides in different substrates used in the production of citrus seedlings. Two experiments were carried out in a completely randomized design and 2x6x6 factorial arrangement was applied with four replicates, two herbicides (diuron and sulfentrazone), six doses of each herbicide of diuron (0, 250, 500, 1,000, 2,000 and 4,000 g .ha-1 and sulfentrazone (0, 75, 150, 300, 600 and 1,200 g ha-1) and six substrates: Coconut fiber; soil; black soil of Indian and to mixtures of these with washed sand, in the first experiment. In the other experiment, a completely randomized design was used in a 2x7 factorial scheme with four replicates, two herbicides (diuron and sulfentrazone) and seven doses of each herbicide. The same doses of both herbicides were used in the washed sand substrate (diuron 0 2, 4, 8, 12, 16 and 20 g .ha-1 and sulfentrazone 0, 2, 4, 8, 12, 16 and 20 g ha-1). The indicator plant used was the cucumber (Cucumis sativus var. Aodai). The evaluated characteristics were the determination of the I50 value of the test plant for each substrate as a function of the doses of each herbicide and the estimate of the amount of diuron and sulfentrazone sorbed in each substrate. The results showed that coconut fiber was the substrate that presented the highest sorption of the herbicides followed by black soil of indium and soil and the organic matter contributed as important component of the soil in sorption of herbicides.