Abstract Background Amaranthus palmeri is an economically important plant species worldwide. The rapid growth and competitive potential of crops make A. palmeri a major problem. Studies on the dissemination potential of this weed in Brazil and worldwide are necessary to identify the regions with high climatic potential. Similarly, we analyzed the behavior of the species in the face of predicted climate change. Studies of this type can be performed using ecological niche modeling. Objective This work aimed to determine areas with climatic suitability for A. palmeri in the present and future climates in Brazil and globally. Methods We projected the potential distribution of A. palmeri based on the environmental requirements and stress parameters that limit this species in Brazil. Results For the current climate, our model identified regions with favorable climatic suitability for A. palmeri on most continents. The results showed that the suitability of A. palmeri in the Brazilian territory will decrease owing to predicted climate change. The future model highlighted decreases in the suitable northern, northeastern, and midwestern areas. An annual study of the occurrence of A. palmeri using the weekly growth index predicted by the model showed great potential for the species throughout the year, with a decrease in the driest months (July to August), indicating the preference of the species for moist soils. Tropical and subtropical zones are currently experiencing a reduction in suitable areas because of climate change in northeastern Brazil and western Australia. Temperate zone sites have potential areas of expansion for A. palmeri (northern USA, Russia, and China) under climate change. Conclusions Based on the results of this study, management strategies should be planned to contain the global spread of A. palmeri.

RESUMO Na implantação de lavouras cafeeiras, a adubação fosfatada é um dos manejos de fertilidade do solo mais importantes. Visando minimizar perdas, dentre as opções em uso estão os adubos de liberação lenta de nutrientes, consorciados à inoculação de fungos micorrízicos arbusculares (FMA). Objetivou-se avaliar o crescimento inicial de cafeeiro inoculado com FMA e submetido a diferentes tipos de fertilizantes fosfatados. O experimento foi conduzido em casa-de-vegetação, utilizando-se delineamento experimental em blocos ao acaso, em esquema fatorial 2 x 4, com quatro repetições. O primeiro fator consistiu de presença ou ausência de FMA (Rhizophagus clarus) e o segundo de fertilizantes fosfatado [monoamônio fosfato (MAP)], organomineral peletizado, organomineral granulado e controle (sem adubação). Avaliaram-se a altura de planta, teor de clorofila nas folhas, número de ramos plagiotrópicos, área foliar, massa da matéria seca da parte aérea e do sistema radicular, porcentagem de colonização de raízes e fósforo foliar. A inoculação com FMA, associada ao fertilizante organomineral peletizado, proporcionou maior crescimento da parte aérea e do sistema radicular e maiores teores de fósforo, em relação aos demais tratamentos, podendo ser uma alternativa na implantação ou renovação de lavouras cafeeiras.

ABSTRACT In the establishment of coffee crops, phosphate fertilization is one of the most important soil fertility managements. Aiming to minimize losses, among the options in use are fertilizers with a slow release of nutrients, combined with the inoculation of arbuscular mycorrhizal fungi (AMF). This study aimed to evaluate the initial growth of coffee plants inoculated with AMF and submitted to different types of phosphate fertilizers. The experiment was conducted in a greenhouse, using a complete randomized block design, in a 2 x 4 factorial scheme, with four replications. The first factor referred to the presence or absence of AMF (Rhizophagus clarus) and the second one to phosphate [monoammonium phosphate (MAP)], pelletized organomineral and grainy organomineral fertilizers, as well as a control (without fertilization). The plant height, leaf chlorophyll content, number of plagiotropic branches, leaf area, shoot and root dry matter mass, percentage of root colonization and leaf phosphorus were evaluated. The inoculation with AMF, associated with the pelletized organomineral fertilizer, provided a higher growth for the shoot and root system and higher phosphorus contents, in relation to the other treatments, and it can be an alternative to the implantation or renewal of coffee crops.