As aplicações de herbicidas em pré-emergência têm por finalidade a obtenção da atividade residual no início do ciclo das culturas e a supressão de novos fluxos de plantas daninhas. Contudo, esse efeito pode prejudicar culturas subsequentes, dependendo da variedade utilizada e da persistência do herbicida no solo. Em virtude disso, o presente trabalho teve como objetivo avaliar o efeito de carryover em cultura subsequente, como soja RR, feijão e milho, proporcionado pelos herbicidas trifluralin e S-metolachlor. Os herbicidas foram aplicados em pré-emergência 120 dias antes da semeadura das culturas. As doses de trifluralin utilizadas (kg ha-1) foram: 0,00; 0,27; 0,54; 1,08; 2,16; e 4,32, e as de S-metolachlor (kg ha-1): 0,00; 0,36; 0,72; 1,44; 2,88; e 5,76. Para o herbicida trifluralin, pode-se observar apenas redução do teor de clorofila (mg cm-2) e na quantidade de massa seca produzida pelas plantas de feijão (IAPAR 81) aos 28 dias após o plantio (DAS), ao passo que em plantas de soja RR (CD 214) foi observada apenas a redução da massa seca. No caso do S-metolachlor, o herbicida provocou redução na altura e injúrias nas plantas de feijão aos 7 e 14 DAS, além da redução nos teores de massa seca. Em plantas de soja, o S-metolachlor alterou a quantidade de massa seca produzida e provocou fitointoxicação leve a moderada. Esses resultados mostram que, de acordo com a dose utilizada, tanto trifluralin como S-metolachlor podem provocar efeitos negativos nas culturas de soja RR (CD 214) e feijão (IAPAR 81), aplicados em pré-emergência 120 dias antes da semeadura das culturas. No entanto, esses herbicidas não interferiram no desenvolvimento das plantas de milho.

In the state of Minas Gerais, the northern region is one of the main banana production cores. Weed interference can reduce crop growth and, consequently, lead to reduced yield and fruit quality. Therefore, the objective of this study was to evaluate the interference of weeds in the production of the first and second cycles of ‘Prata-Anã’ bananas. The experimental design was randomized blocks, with ten treatments and three replicates, evaluated in two crop cycles. The treatments were ten periods of weed control, from planting: without control; control throughout the whole experimental period; control only in the first month after planting; control until the second; third; fourth; fifth; sixth; eighth and tenth months after planting. The agronomic and productive characteristics of the ‘Prata-Anã’ bananas were evaluated aton harvest. The maintenance of ‘Prata-Anã’ bananas without weed coexistence for up to 30 days after planting was enough to obtain fruits with satisfactory quality and productivity, both in the first and in the second production cycle, without altering the vegetative and reproductive cycles.

The evaluation of agronomic characteristics of crops is important because they may be influenced by the height, density and spatial arrangements of eucalyptus in an agroforestry system. These silvicultural characteristics may interfere with height and productivity of crops between the rows of the tree component due to shading, competition for water and nutrients. The objective of this study was to evaluate the effect of the assessed site on some agronomic characteristics such as height, grain yield and effective yield of BRS 655 forage sorghum (Sorghum bicolor (L). Moench) with different clones and arrangements of eucalyptus in the north of Minas Gerais. Experimental randomized block with a split-plot design and five replications was used to evaluate sorghum. The effective productivity and height of sorghum comparing to the average values in the area were low. The GG 100 clone (Eucalyptus urophylla × E. grandis ) showed low adaptation to semi-arid region while the MA 2001 clone (Eucalyptus camaldulensis × E. Tereticornes) presented greater height. The low values of some agronomic characteristics of sorghum were due to the distance between the rows of eucalyptus. The 2 × 3 + (15 m) and 2 × 3 + (20 m) arrangements of eucalyptus generated higher sorghum plants regardless of the clone.