BACKGROUND: Soybean seed treatment with fungicides is a well-established disease management strategy. However, the movement of these fungicides within seedlings is not always well characterized. Thus, the objectives of this study were to determine the pattern of translocation of three fungicides with different modes of action applied as a seed treatment, and the effect of soil type on translocation.RESULTS: Most of the absorbed radioactivity was concentrated in the cotyledons and the maximum sum of the rates of absorption by roots, stems, and leaves of the plants was 15%. In most cases, absorption by roots, stems, and leaves were lower than 5% for 14 C-pyraclostrobin and 14 C-metalaxyl, and 1.6% for 14 C-carbendazim. Fungicides absorbed by the roots and the whole seedlings were higher when plants were grown in soil with lower organic matter content. Fungicides in the cotyledons are unlikely to be redistributed and are lost when cotyledons fall off the plants.CONCLUSION: Cotyledons are the part of the plant where fungicides are most absorbed, regardless of the fungicide. Soil type affects the absorption of fungicides, and in this study it was most likely caused by soil organic matter. These data improve knowledge of the movement of seed treatment fungicides in soybean seedlings and may help the development of seed treatment chemistry to manage seed and soilborne pathogens.

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The objective of this paper was to assess the efficiency of photosynthetically active radiation (PAR) intercepted in dried phytomass of soybean cultivars of determinate and indeterminate growth habits in different spatial arrangements. All experiments were carried out during the 2013/2014 crop year, two soybean cultivars (BMX Ativa RR/determinate and BMX Turbo RR/indeterminate) in a spatial arrangements (45, crossed, 20, 20 × 40, 20 × 60, 20 × 80 cm). Starting from first emergence up to the point of maturation, 14 phytomass assessment were evaluated with seven days interval, in which one plant was sampled per repetition. Greater conversion efficiencies of solar radiation were obtained in paired arrangements. Paired arrangements, and 20 cm, lead to a greater leaf area index, and possibly a greater interception of the diffused radiation and an increase of conversion efficiency and the overall cultivation productivity of BMX Ativa RR and BMX Turbo RR.

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The West African Economic and Monetary Union (abbreviated as UEMOA from its name in French: Union Économique et Monétaire Ouest-Africaine) is an organization of eight West African countries: Benin, Burkina Faso, Ivory Coast, Guinea-Bissau, Mali, Niger, Senegal and Togo. This region suffers an agricultural yield gap mainly due to misplanning of crop zoning. Our study aimed to perform an agricultural zoning for maize and soybean in the UEMOA region based on (i) potential yield (carbon dioxide, temperature, photosynthetically active radiation, photoperiod and genotype), (ii) attainable yield, under high crop management and technology inputs and (iii) actual yield. Results show that the UEMOA region is very suitable for growing maize and soybeans; however, a large gap exists between attainable and actual yields. It is shown that the adoption of better management and technology strategies is a way to greatly increase local yields.