Abstract Background Weed interference in the early stages of soybean development can compromise its yield. The use of herbicides with residual effects at the time of sowing is an alternative to reduce weed density and emergence time, consequently, the damage caused by their interference. Therefore, weed development can be reduced, which can result in easier post-emergence control. The combination of herbicide modes of action extends the spectrum of control and delays herbicide resistance evolution. Objective This work aimed to determine the onset of the critical period of weed control (CPWC) from the application of residual herbicides mixtures at soybean sowing. Methods Two experiments were carried out in 2021/2022, the first in a conventional tillage system with increasing periods of soybean/weeds coexistence (14, 28, 42, and 56 days after crop emergence). The second experiment consisted of a no-tillage system with soybean/weeds coexistence for 30, 45, 60, 75, and 90 days after crop emergence. On the day of soybean sowing, mixtures of the herbicides diclosulam + pyroxasulfone, flumioxazin + pyroxasulfone and diuron + sulfentrazone were applied, in addition to the untreated check. Soybean yield was evaluated evaluated upon harvest and data compared by non-linear regressions to CPWC determination. Results The application of residual herbicides can allowing reduces losses relative to the untreated control by up to 57%. CPWC beginning can be extended from eight to forty days, depending on mixes and acceptable losses. Conclusions The use of the mixture of residual herbicides are a good option for weed interference reduction for soybean crop.

Resumo O objetivo deste trabalho foi comparar a relação altura-diâmetro, descrita por modelos biológicos não lineares, de Eucalyptus benthamii em monocultura florestal e em três diferentes sistemas de integração lavoura-pecuária (ILP): lavoura-floresta, pecuária-floresta e lavoura-pecuária-floresta. As árvores foram avaliadas durante sete anos após o plantio. Cinco modelos biológicos não lineares foram ajustados para avaliar a relação altura-diâmetro, e o modelo de Gompertz foi selecionado para descrever os dados, embora todos os modelos tenham descrito satisfatoriamente a relação altura-diâmetro das árvores nos ILP. A análise dos dados mostrou que não há nenhuma semelhança entre a monocultura florestal e os ILP quanto à relação altura-diâmetro. Além disso, a relação altura-diâmetro de E. benthamii muda entre os diferentes ILP. Particularmente, dois sistemas com bovinos fornecem os mesmos valores de taxa máxima de crescimento, assíntota e ponto de inflexão do diâmetro à altura do peito. Além disso, com a integração do gado no componente arbóreo, as árvores produzidas apresentam menores alturas assintóticas, com maiores diâmetros quando as alturas médias das árvores dos ILP são iguais.

Abstract The objective of this work was to compare the height-diameter relationship, described by nonlinear biological models, in Eucalyptus benthamii in monoculture forestry and in three different integrated crop-livestock systems (ICLS): crop-forestry, livestock-forestry, and crop-livestock-forestry. The trees were evaluated during seven years after planting. Five nonlinear biological models were fitted to evaluate the height-diameter relationship, and Gompertz’s model was selected to describe the data, although all models described satisfactorily the height-diameter relationship of the trees in the ICLS. The analysis of the data showed that there is no similarity between monoculture forestry and the ICLS as to the height-diameter relationship. In addition, the height-diameter relationship in E. benthamii changes between the different ICLS. Particularly, two systems with cattle provide the same values of maximum growth rate, asymptote, and inflection point of diameter at breast height. Furthermore, with the integration of cattle into the tree component, the produced trees show lower asymptotic heights, with larger diameters when the average tree heights of the ICLS are equal.