INTRODUÇÃOO Brasil é um dos países que tem maior área agrícola cultivada em sistema plantio direto (SPD), com 31,8 milhões de hectares, que correspondem a mais da metade da área agrícola do País (Febrapdp 2012). A acidez do solo é um dos fatores mais limitantes à produtividade das culturas, no mundo (Fageria 2001), sendo a calagem utilizada para a sua correção. , com incrementos de 9,3 %, para o milho, e 11,4 % e 11,3 %, respectivamente com e sem calcário, para a soja. PALAVRAS-CHAVE:Zea mays L.; Glycine max (L.) Merrill; acidez do solo.Gypsum and lime increase soybean and maize yield and decrease drought stress During the maize and soybean cultivation process, water deficit occurs frequently and can reduce grain yield. Gypsum can be used to mitigate yield losses. This study aimed to evaluate the influence of gypsum application, with and without lime, on soil chemical properties and maize and soybean yield, in a no-till system. The experimental design was completely randomized, with six gypsum doses (0 t ha -1 , 0.5 t ha -1 , 1 t ha -1 , 2 t ha -1 , 4 t haand 8 t ha -1 ), lime application and four replications, for maize. For soybean, a 6 x 2 factorial scheme, with six gypsum doses (0 t ha -1 , 0.5 t ha -1 , 1 t ha -1 , 2 t ha -1 , 4 t ha -1 and 8 t ha -1 ), with and without lime application, and four replications was used. Soil chemical attributes and maize and soybean grain yield were evaluated. Gypsum increases the Ca 2+ levels, redistributes Mg 2+ to the 10-20 cm and 20-40 cm depth layers and decreases the Al 3+ contents in the 20-40 cm layer. Liming increases pH in the 0-10 cm depth layer and pH is not affected by the gypsum application. Gypsum increases maize and soybean grain yield, with response up to the 2 t ha -1 dose, with increments of 9.3 %, for maize, and 11.4 % and 11.3 %, respectively with and without lime, for soybean. KEY-WORDS: Zea mays L.; Glycine max (L.) Merrill; soil acidity.

The rootstock influences the agronomic performance of fruit plants. In Prunus persica (peach), particularly those varieties produced in Brazil, this relationship is not well understood. We, therefore, set out to evaluate the performance of the peach cultivar Maciel with eight rootstocks, Aldrighi, Capdeboscq, Flordaguard, Nemaguard, Okinawa, Umezeiro, Tsukuba, and Seleção Viamão, planted in 2006 and evaluated in the 2014/2015 and 2015/2016 seasons. Phenology of flowering, trunk diameter, canopy volume, fruit number, and yield were evaluated in the field. For the fruit, we evaluated the mass, diameter, color, flesh firmness, soluble solids concentration, titratable acidity, concentration of total phenolic compounds, carotenoids, and antioxidant activity. Plants from the Aldrighi and Nemaguard rootstocks flowered earlier than plants from the other rootstocks in 2014, and in 2015, flowering was variable in all rootstocks. The cultivar Maciel on Umezeiro had low vigor, trunk diameter, and canopy volume. On Aldrighi, Capdeboscq, Flordaguard, Nemaguard, and Tsukuba this cultivar showed good production rates. The fruit color, flesh firmness, concentration of soluble solids, total phenolics, antioxidant activity, and total carotenoids were influenced by rootstock and harvest.

Thinning is a cultural practice that leads to balance between fruit yield and quality. It is carried out in a short period of time and requires qualified workforce, whose shortage ends up increasing costs. This study aimed at evaluating the thinning effect of metamitron on peach trees at different periods of time after bloom. The experiment was carried out in a commercial orchard of 'Sensação' peach trees located in Morro Redondo, Rio Grande do Sul (RS) state, Brazil, in 2015-2016 crops. Treatments were the application of 200 mg L-1 metamitron, 20, 30, 40, 50 and 60 days after full bloom (DAFB), and manual thinning 40 DAFB. Fruit abscission, effective fructification, period of manual and chemical thinning, number of fruits and yield per plant, mean fruit mass and fruit caliber were evaluated. When metamitron was applied 40 DAFB, percentages of fruit abscission and fruit set, besides the number of fruits, were similar to the ones found when manual thinning was carried out. The intensity of the thinning effect of metamitron in peach trees depends on the application period.

High effective peach fruit set results in an excessive amount of fruits, requiring thinning accomplishment, which is a manual practice and demands specialized labor, raising production costs. In this sense, chemical thinning may be an alternative to improve the peach production chain. The objective of this work was to evaluate the efficiency of 6-benzyladenine (BA) on chemical thinning and the effect of different BA dosages on peach production and color characteristics of 'Maciel' fruits. Treatments consisted of plants without thinning (Control), sprayed BA at doses of 100 mg L-1 , 200 mg L-1 and 400 mg L-1 , applied 45 days after full bloom (DAPF) and hand thinning at 45 DAPF. The applications of different dosages were carried out by spraying, using backpack spraying equipment. Percentage of thinning abscission, number of fruits per plant, yield per plant, fruit mass, color and average fruit diameter were evaluated. The doses of 200 and 400 mg L-1 BA for thinning increased the percentage of fruit abscission and fruit mass. The doses of 400 mg L-1 BA presented lower yield per plant, but fruits with higher average mass. Increasing BA dose reduced the number of fruits per plant. Hand thinning and 400 mg L-1 BA resulted peach fruits with larger diameter. BA application to thin peaches did not alter the fruit skin color. Therefore, BA may be a chemical thinning alternative for 'Maciel' peach cultivar, because it reduces the time of thinning in plants when compared to manual thinning. For an efficient chemical thinning with BA the product dose must be taken into account, along with climatic conditions and the cultivar.

In the peach tree cultivation, the producer has the challenge of obtaining good quality fruits and maintaining production in a balanced way over the years. Thinning favors these parameters and reduces the fruit load on plants. Manual thinning commonly practiced on peach trees requires high labor and increases production costs. Chemical thinning as an alternative to manual thinning, which depending on the species, time and concentration, has demonstrated high efficiency. The aim of this study was to evaluate the effect of metamitron applied at different seasons and concentrations on the chemical thinning of peach trees in southern Brazil. Experiments were conducted in a commercial peach orchard (‘Maciel’ cultivar), in the municipality of Morro Redondo, Rio Grande do Sul, Brazil, during the 2015 and 2016 harvests. In experiment 1, metamitron at concentration of 200 mg L-1 was applied at 20, 30, 40, 50 and 60 days after full bloom and manual thinning performed at 40 days after full bloom. In experiment 2, metamitron was applied at concentrations of 100 mg L-1, 200 mg L-1, 300 mg L-1 and 400 mg L-1 and manual thinning at 40 days after full bloom, in addition to control plants. Fruit abscission, fruit set, total number of fruits per plant, yield per plant, average mass and fruit diameter were evaluated. Metamitron at concentration of 200 mg L-1 has thinning effect when applied before 40 days after full bloom. Metamitron concentration of 100 mg L-1 applied at 40 DAFB promoted fruit abscission superior to manual thinning. Therefore, the application of metamitron to ‘Maciel’ peach trees close to full bloom at concentration of 100 mg L-1 results in thinning practice similar to manual thinning.

Aims: The objective of this study was to evaluate peach fruits quality after chemical thinning using metamitron at different times in the South of Brazil. Study Design: The experimental design was in randomized blocks, with five replications of three plants, fruits were harvested and evaluated the central plant in the plot, and twenty fruits were evaluated in each replicate.

Resumo Kiwis minimamente processados necessitam de técnicas para manter a qualidade dos frutos durante a conservação e o período de prateleira. Aditivos combinados à radiação ultravioleta podem ser uma alternativa para assegurar a qualidade das frutas por mais tempo de conservação. Neste contexto, foi proposto avaliar a eficiência do uso da radiação UV-C e diferentes aditivos na prevenção do escurecimento e conservação de kiwis ‘Bruno’ minimamente processados. As fatias de kiwi foram submetidas a soluções contendo os seguintes tratamentos: controle, ácido ascórbico a 1%; isoascorbato de sódio a 1%; ácido cítrico a 1%, depois, utilizou-se por dois minutos a radiação UV-C na intensidade de 2,71 kJ m-2. As bandejas foram armazenadas em câmara fria a 4 ± 1 ºC de temperatura, com umidade relativa de 85% a 90%, e armazenadas por períodos de 3, 6 e 9 dias. Avaliaram-se perda de massa, coloração da polpa, sólidos solúveis, acidez titulável, incidência de podridão, compostos fenólicos totais e atividade antioxidante. O uso de aditivos melhora a conservação do kiwi minimamente processado, com destaque para o isoascorbato de sódio e o ácido cítrico. Os frutos de kiwi da cultivar ‘Bruno’ podem ser armazenados por até 6 dias sob refrigeração com o uso de aditivos. Após esse período, a perda de massa é elevada. O uso de UV-C não alterou a qualidade dos kiwis durante o armazenamento, podendo ter seu uso dispensado.

Among the factors that affect peach productivity is the proper nutrition of plants, being nitrogen (N) one of the main nutrients for the crop. Thus, the objective of the current study was to evaluate the effect of nitrogen fertilization on macronutrient leaf contents, plant development and production of different genotypes of peach trees cultivated at high planting density, seeking to recommend the most appropriate concentration. The experiment was conducted between 2016 and 2018 using peach selections ‘Cascata 1513’ and ‘Cascata 1067’ and with nitrogen fertilization concentrations (0, 60, 120 and 180 kg ha-1 of N). Pruning mass, trunk diameter, number of fruits per plant, average fruit mass, yield per plant, yield per hectare and leaf macronutrients were evaluated. The increase of N concentration increases the N content in leaves. For the conditions of this experiment the maximum production per plant was obtained for the highest dose of 180 Kg ha of N.