RESUMEN
This study aimed to evaluate the effects of low doses of the herbicide glufosinate-ammonium in different application modes in the vegetative development of upland rice. The treatment consisted of a combination of five low doses (0; 15; 30; 60; and 100 g a.i. ha-1) of the herbicide glufosinate-ammonium and four application modes of the low doses: single between active tillering (AT) and floral differentiation (FD); single after FD; split in two (the first at the beginning of the AT and the second between AT and FD; split in three (the first at the beginning of the AT, the second between the AT and the FD and the third after the FD, with. There was no hormesis effect on rice crop due to low doses of glufosinate-ammonium. The vegetative development of rice plants was reduced by the application of low doses in all application modes with lower plant height, dry weight, number of panicles, and effective tiller.
Asunto(s)
Aminobutiratos , Herbicidas , Hormesis , Oryza , Aminobutiratos/farmacología , Herbicidas/farmacología , Oryza/efectos de los fármacosRESUMEN
The aim of this research was to verify the effect of glyphosate low doses on leaf macronutrient levels and vegetative traits of upland rice in two growth stages. The treatments were arranged in 2 × 6 factorial scheme. The first factor consisted of applications in two growth stages of rice crop (tillering and floral differentiation) and the second factor was the low doses of glyphosate (0, 10, 20, 40, 70 and 100 g e.a. ha-1). In full bloom, the chlorophyll content was determined in a sample of 30 flag leaves. In these leaves, the contents of macronutrients were determined. At the maturity of the rice plant, the stem count was performed per m2, effective tiller and the plant height was measured. The low doses did not influence the leaf content of macronutrients. The plant height was reduced with an increase in the low doses of glyphosate, having a greater effect on the floral differentiation stage. When applied low doses of glyphosate at the floral differentiation stage, chlorophyll content increases and when applied to tillering there is a linear decrease in chlorophyll content. The number of stems increases with the application of low doses at floral differentiation.