The incidence of many malnutrition-related diseases among the populations of developing countries is closely related to low dietary zinc (Zn) intakes. This study evaluated the potential of agronomic biofortification of lettuce genotypes with Zn in different soils. We evaluated the ability to biofortify three lettuce genotypes (‘Grand Rapids’, ‘Regina de Verão’, and ‘Delícia’) in two soils (Red-Yellow Latosol and Dystroferric Red Latosol) using five doses of Zn (0, 5, 10, 20, and 30 mg kg⁻¹). At 55 days after sowing, the plants were harvested. There was an interaction among the soils, genotypes, and Zn doses. Regardless of the soil and genotype, the increase in Zn supply promoted a linear increase in shoot Zn concentration. However, shoot and root dry matter yields were differentially affected by Zn supply according to the genotype and soil type. Overall, the Red-Yellow Latosol provided a higher shoot Zn concentration but also caused greater growth damage, especially in ‘Regina de Verão’ and ‘Delícia’. ‘Grand Rapids’ was biofortified the most in Red-Yellow Latosol.

<![CDATA[Potassium contained in sugarcane straw quickly returns to the soil in a form readily available to crops. Thus, the objective of this study was to evaluate the effect of potassium on the nutritional status and grain yield of peanutscultivated in succession with sugarcane harvested without burning. The experiment was installed in Jaboticabal, São Paulo, Brazil, in Dystrophic Red Latosolcultivated with the peanut crop, variety Runner IAC 886. The treatments consisted of the application of 30, 60, 90 and 120 kg ha-1 of K2O and a control (no potassium). The experimental design adopted consisted of randomized blocks with five replications. Parameters evaluated were height, diameter, number of leaves, nutritional status for potassium and grain yield. Potassium resulted in a significant increase in the number of leaves and height, K contents (50-70 g kg-1) and grain yield, obtaining 2790 kg ha-1 at a dose of 120 kg ha-1. The sugarcane straw alone is not sufficient to meet the nutritional needs of peanuts planted in succession with sugarcane, where application of potassium fertilizer is necessary to obtain high yields.Potassium fertilization improved the nutritional status and was reflected in the increased production of grains of peanuts grown in rotation with sugarcane, especially at the dose of 120 kg ha-1 K2O.]]>

O selênio (Se) é um importante elemento ligado a processos fisiológicos na planta, microrganismos, animais e seres humanos. No entanto, para as plantas, seu modo de ação e sua essencialidade são ainda motivos de controvérsia. No Brasil, é relevante a falta de informações sobre o Se nas culturas agrícolas, havendo ainda indicativo de baixa ingestão desse elemento pela população. Assim, este estudo objetivou avaliar a influência da aplicação de selenato e selenito na biofortificação com Se e o efeito dessas formas de Se nos teores de macro e micronutrientes em cultivares de alface. Utilizou-se o delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 3 x 2, sendo cinco cultivares de alface (Maravilha de Verão, Rafaela, Great Lakes, Veneranda e Vera), três concentrações de Se (0, 10 e 20 μmol L-1) e duas formas de Se (selenato e selenito), com quatro repetições. Os resultados encontrados mostram que, para o cultivo de alface em solução nutritiva, o selenato foi mais indicado para a biofortificação com Se, enquanto o selenito mostrou ser mais tóxico. A aplicação do selenato resultou em aumento no teor de S na parte aérea, enquanto o selenito reduziu o teor de P, e ambas as formas de Se diminuíram os teores de micronutrientes. Entre as cultivares de alface, não se observou variação genotípica para o teor de Se, e pequena variação foi verificada para produção de matéria seca da parte aérea e teores de S, Mg, Mn e Fe.

Information on the nutritional status of plants enables adequate fertilisation management. Thus, the aim of this study was to evaluate how nutritional disorders alter the biological, nutritional and biochemical mechanisms of broccoli (Brassica oleracea var. italica L.) plants grown under greenhouse conditions. A complete nutrient solution and omissions of macronutrients were tested in a completely randomised design with four replicates. Broccoli plants grown with the omission of N and Ca were the first of show deficiency symptoms and the greatest reduction in the net photosynthetic rate and stomatal conductance, with evidently impaired plant growth and biomass. Omissions of macronutrients affected carbohydrate partitioning, and the content of soluble sugars significantly decreased by more 60% in response to Mg omission. With K omission, the contents of soluble sugars and starch increased in broccoli leaves by 40% and 60%, respectively. K transport increased in plants grown without Ca. S translocation decreased with the absence of any macronutrient in the nutrient solution. Deficiencies in the nutrients N, K, and Ca cause the most critical early damage in the photosynthetic apparatus and in the nutritional balance of broccoli plants, so attention should be given to replenishing these nutrients in plantations.