Uso de submodelo de competição por plantas daninhas no modelo SimulArroz

Abstract

In version 1.1 of SimulArroz there isn’t the option of weed competition. The objective was to introduce in SimulArroz the option of yield loss by weedy rice (Oryza sativa) or barnyard grass (Echinochloa spp.) on irrigated rice. The competition of weedy rice and barnyard grass on yield was modeled by the method of yield loss, using the equation of the rectangular hyperbola. The coefficients i and a of the rectangular hyperbole referring to each of these weeds were obtained from the literature and field experiments conducted in 2016/2017 to Rio Grande do Sul. In the SimulArroz source code, yield loss was implemented to penalize yield in the three technological levels (high, medium and low) in physiological maturity. In the classification of coefficients, were found values of imédio =1.04, 1.50 and 3.57 for low, medium and low levels respectively, to the weedy rice, and the coefficient a = 100 for the three levels. For barnyard grass, the values of imédio = 4.70, 10.49 and 15.51 and value of amédio = 101.63, 104.92 and 96.88 were respectively high, medium and low. The performance was evaluated by root mean square error (RMSE), normalized root mean square error (RMSEn), “BIAS” index, modified concordance index (dw) and Nash-Sutcliffe efficiency coefficient (COE), with observed data from experiments and evaluations on commercial fields. It was concluded that was possible to introduce the yield loss by weedy rice or barnyard grass on the yield of irrigated rice in SimulArroz.