Climate zoning: identifying suitable regions for the occurrence of Alternaria Brown spot in tangerine trees in Brazil.

BACKGROUND: Brazilian citrus farming has been migrating to nontraditional citrus-growing regions, which can be considered a challenge for citrus growers, as not all these areas are suitable for tangerine cultivation. Thus, the mapping of regions exhibiting favorable climatic conditions for Alternaria brown spot has become crucial in the selection of appropriate locations for the establishment of new orchards. This mapping enables the implementation of an avoidance strategy, which entails steering clear of areas where the disease is prevalent, aligning with fundamental principles of disease control. RESULTS: Thus, this study seeks to zone areas with high and low climatic favorability for the occurrence of Alternaria brown spot in tangerine trees in Brazil. Historical climate data series from the NASA-POWER database were used for all municipalities in Brazil. Agrometeorological variables used to determine the development of Alternaria brown spot were average monthly air temperature (Tmean) and duration of leaf wetness period (LWD). Areas were considered unsuitable climatically when Tmean was <17 °C or >33 °C, relatively suitable when Tmean was between 13 °C and 33 °C and LWD <10%, and climatically suitable when Tmean was between 13 °C and 33 °C and LWD >10%. The states of Paraná, Santa Catarina and Rio Grande do Sul showed greater thermal amplitude within months and throughout the year. The southern region of the country has harsher winters, with minimum temperatures below 15 °C, which is unfavorable for the disease incidence. CONCLUSION: The states with the greatest favorability for Alternaria brown spot were Paraná, Santa Catarina, and Rio Grande do Sul, mainly from May to September. Rio Grande do Sul was the state in this region that showed the greatest favorability, as a consequence of leaf wetness exceeding 10 h. The main tangerine-producing regions in Brazil, including the southern part of Minas Gerais, the state of São Paulo and the metropolitan region of Porto Alegre, were mostly classified as relatively favorable areas for the occurrence of Alternaria brown spot. It is recommended that when establishing new tangerine orchards, regions with lower favorability for the occurrence of Alternaria brown spot, such as the North and Central-West regions of Brazil, particularly the states of Amazonas, Pará and Mato Grosso, should be selected. © 2023 Society of Chemical Industry.

Climate risk zoning for wheat crops in the southeastern region of Brazil.

BACKGROUND: Wheat (Triticum aestivum L.) is the second most consumed food in the world. One way to meet this demand is the expansion of wheat cultivation to the Brazilian Cerrado in the southeastern region. However, one of the major limitations is that there are few studies related to wheat climate risk zoning. Thus, this study aimed to determine the agroclimatic zoning of wheat by estimating the water needs satisfaction index (ISNA) in the southeastern region of Brazil. For this purpose, a 60-year historical series of meteorological data was used to calculate the potential evapotranspiration, crop evapotranspiration, and climatological water balance values. To define the agroclimatic zones of wheat and sowing date, the ISNA method was used. The data were analyzed using descriptive statistics to determine the variations. To obtain the agroclimatic zoning of wheat, the geostatistical method of kriging interpolation was used. RESULTS: The regions with the highest rainfall are the south of Minas Gerais and the coast of São Paulo. The sowing period directly impacts the development of the crop, the available water capacity and the ISNA values indicated the spring and summer had better cultivation conditions, and the best window for wheat cultivation is concentrated in the fall due to the limitation of biotic factors. CONCLUSION: In terms of altitude (>700 m), Minas Gerais has 39.4% of the area suitable for wheat cultivation. Thus, climatic variations within and between the states of the southeastern region should be considered for the positioning of wheat cultivars in these regions to obtain the maximum yield. © 2023 Society of Chemical Industry.

The times, movements and operational efficiency of mechanized coffee harvesting in sloped areas.

Coffee farms have been adopting the microterraces system, a technique that reduces the effect of the slope by moving the soil between the crop lines. In this way, all the mechanized operations can be carried out normally, except for harvesting, due to the work limitation of the harvesters, who work in areas with a maximum slope of 20%. One option is to use unilateral harvesters, which crop one side at a time; however, there has been no research on these microterrace machines to evaluate their performance and to compare it with those of the other harvesting methods in those regions. This study aimed to compare the mechanized harvest performance in the microterraces with the manual and semimechanized harvesting methods. The study was carried out in an agricultural area of the municipality of Ouro Fino / MG, Brazil, in a crop production site where the microterraces were built six years before the experiment. The treatments were assigned to a split-block design with seven repetitions and consisted of mechanized harvest-unilateral harvester with bag storage; manual harvest-regionally experienced workers; and semimechanized harvest-with portable breakers. Through an analysis of the times and movements, the operational efficiency and operational and effective field capabilities were measured. The adoption of microterraces allows the efficient mechanization of areas previously impossible to mechanize. The unilateral harvester is a potential tool for the partial replacement of manual labor in the harvest, performing a service equivalent to that of 23.68 manual workers and 10.55 manual workers in the semimechanized system.

Development of an electrohydraulic drive system for the vibrating conveyor belt of the peanut digger-inverter.

Hydraulic systems are equipment widely used in stationary industrial equipment and in moving agricultural equipment and construction machines. Currently, the rotation of the vibrating conveyor belt of the peanut digger-inverter is triggered by the tractor power take-off. Considering that for the equipment to operate at its optimal, the tractor engine needs to work at low rotation, responsible for the rotation of the power take-off, this work aimed at developing an electro-hydraulic system able to transmit varying work rotations to the vibrating conveyor belt of the digger-inverter, regardless the rotation of the power take-off and the speed used in the tractor. The electro-hydraulic system uses the oil of the auxiliary hydraulic system (remote control) and electric power of the tractor battery. The rotation of the hydraulic motor that drives the vibrating conveyor axis is controlled by a proportional flow control valve while the direction of rotation is determined by an electro-hydraulic directional valve, controlled by a Vcontrol Personal Device Assistant controller installed in the tractor cab. The electro-hydraulic system developed can be used to control the rotation of the vibrating conveyor belt of the peanut digger-inverter since it meets the torque and power requirements necessary to move the vibrating conveyor belt, with the respective rotation control.