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Abstract: In Theobroma grandiflorum (cupuassu) orchards, efficient nutrient management is essential to achieve high yields and fruit quality. Thus, fertilization programs should be guided by the concentration of nutrients exported by fruits, as observed with other fruit species. The aim of this study was to quantify the export of macro and micronutrients by fruits of cupuassu genotypes, in order to guide nutrient replacement recommendations replacement. Six cupuassu genotypes (‘BRS Careca’, ‘BRS Fartura’, ‘BRS Duquesa’, ‘BRS Curinga’, ‘BRS Golias’ and ‘genotype 63’) were used, and 40 fruits per genotype were sampled, totaling 240 fruits, in the municipality of Tomé-Açu (Pará/Brazil). Fruits were broken and manually pulped and then separated into peel, seed and pulp. In each fruit part, the contents of macro and micronutrients were analyzed, and later extrapolated to ton of fresh fruits. Potassium was the macronutrient most exported by cupuassu fruits, and ‘genotype 63’ accounted for the largest exports per ton of fresh fruits of this nutrient. The export of nutrients per ton of fresh fruits followed this order for macronutrients (kg ton-1): K (4.34), N (2.73), P (0.54), Mg (0.40), S (0.29), Ca (0.26) and for micronutrients (g ton-1): Zn (6.24), Fe (4.97), Mn (3.49), Cu (2.45), Ni (0.18) and Mo (0.11). The average replacement per plant and per year, during the productive phase, for the five Cupuassu genotypes is 471 g of K2O, 326 g of N, 245 g of P2O5, 27 g of CaO, 56 g of MgO, 63 g of SO4-2 and 15 g of Fritted Trace Elements (FTE).

Jambu, a plant native to the Amazon, is rich in essential oils, particularly spilanthols and phytols. Although hydroponic cultivation of this vegetable is practiced, the process remains relatively understudied. In this context, this study aimed to assess the influence of electrical conductivity of nutrient solutions on jambu production. Greenhouse experiments were conducted at Universidade Estadual do Norte Fluminense (UENF), Brazil, employing a randomized block design encompassing six blocks comprising six Hoagland and Arnon nutrient solutions with electrical conductivities of 0.5, 1.0, 2.0, 2.5, 3.0, and 4.0 mS cm−1. Harvesting occurred 72 d after sowing, and the plants exhibited improved growth at electrical conductivity close to 3.5 mS cm−1. The levels of N, P, K, B, Zn, Mn, and essential oils of jambu plants increased linearly with increasing electrical conductivity. Twenty-three compounds were detected among the investigated essential oils, with spilanthol, phytol, and acmellonate present in the highest amounts. Increase in electrical conductivity led to increases in the percentage areas of several compounds, such as (Z,Z)-1,8,11-heptadecatriene, caryophyllene, 6-pentadecen-1-ol, 1-pentadecene, spilanthol isomer 1, (E)-β-ionone, kessane, and caryophyllene oxide. Furthermore, higher electrical conductivity resulted in decreasing percentages of compounds such as spilanthol, phytol, and Compound 2. Notably, a 609.74 % increase in caryophyllene and a 25.65 % reduction in spilanthol were observed with increasing electrical conductivity. These results suggest that the productivity of jambu plants is improved, including the production of essential oils, with cultivation in solutions with electrical conductivities above 2.5 mS cm−1. However, this condition may negatively affect most cultivated vegetables. The mechanisms underlying the increased tolerance of jambu to higher electrical conductivities require further investigation.

Objetivou-se avaliar a germinação da semente de lichia, com tratamentos pré germinativos em função do tempo de armazenamento. Foram coletados frutos uniformes de lichieiras sadias, onde parte foi armazenada em geladeira e outra parte teve suas sementes extraídas manualmente e armazenadas em geladeira e em ambiente natural. Sementes de um dia foram submetidas aos tratamentos pré germinativos com imerssão durante 30 minutos em: água (25°C), Gelo (0°C); solução de KCl 5 g.L-1; solução de GA3 1000 mg.L-1; solução de GA3 2000 mg.L-1; solução de GA3 3000 mg.L-1; solução de GA3 4000 mg.L-1 e submetida a Geladeira por 24 horas (10°C), semeadas em papel germitest e colocadas em câmara BOD temperatura 25°C, iluminação 12/12 horas. Este procedimento foi repetido para sementes armazenadas por 30 e 60 dias e para sementes retiradas de frutos armazenados por 30 e 60 dias. O modelo experimental foi inteiramente casualisados, sendo oito tratamentos e quatro repetições de 50 sementes. As sementes de lichia armazenada por 30 dias em geladeira não apresentoaram resultado satisfatório na germinação, sementes armazenadas em ambiente natural por 30 dias e por 60 dias em geladeira não germinaram, sendo que o tratamento com giberelina foi benéfico à geminação.

The present study evaluated the effect of arbuscular mycorrhizal fungi (AMF) inoculation on growth and nutrition of Euterpe edulis seedlings, supplemented or not with phosphate fertilization. The experiment was conducted in a greenhouse. The randomized block design, consisted of a 3x2 factorial arrangement and 4 replicates, with two phosphorus doses (0 and 50 mg dm-3 of soil), two microbiological treatments (Rhizophagus clarus; laroideoglomus etunicatum; R. clarus + C. etunicatum) and control (without fungus). Sowing and inoculation occurred concurrently in 2 kg plastic bags. Height, collar diameter, leaf area, dry shoot mass, macronutrient content and mycorrhizal colonization percentage were determined after 226 days. Regarding mycorrhizal colonization percentage, R. clarus resulted significantly beneficial for the production of E. edulis seedlings. In the absence of phosphate fertilization, R. clarus and mixed inoculum increased all biometric variables and macronutrient contents in seedlings. Therefore, it is concluded that AMF inoculations provide beneficial effects for growth and nutrition of E. edulis seedlings, resulting in more vigorous plants at a low-cost strategy. Highlights: • Rhizophagus clarus resulted significantly beneficial for the production of E. edulis seedlings and in the absence of phosphate fertilization, and mixed inoculum ( clarus + Claroideoglomus etunicatum) increased all biometric variables and macronutrient contents in seedlings. • The AMF inoculations provide beneficial effects for growth and nutrition of E. edulis seedlings, resulting in more vigorous plants at a low-cost strategy. • The AMF, a biological agent of mutualistic associations with plants, constitutes an innovative approach to sustainable agriculture, contributing to increase plant survival rate, a key-factor for the successful reintroduction and conservation of E. edulis, as well as for its commercial exploitation.

ABSTRACT Molybdenum (Mo) availability is strongly affected by soil pH, which determines the dynamics of electrical charges and the adsorption of molybdate. This study evaluated the effects of nitrogen (N) and Mo application on the chemical properties of a Latossolo Amarelo (Oxisol) and in Coffea canephora nutrition and productivity throughout two productive cycles under field conditions. The experiment was conducted from June 2018 to May 2020. The experimental design used was in randomized blocks, in a 2 × 5 factorial scheme, the first factor being the absence and presence (4 kg ha-1 yr-1) of molybdic fertilization and the second factor was the N dose (300, 500, 700, 900, and 1,100 kg ha-1 yr-1). At the end of each production cycle, soil samples were collected to evaluate the pH(H2O), pH(KCl), exchangeable aluminum, potential acidity, organic matter, and Mo, at layers of 0.00-0.20 and 0.20-0.40 m. Leaves were sampled from the coffee tree to determine Mo and N contents and the coffee beans were harvested to evaluate the yield of processed coffee. The results showed that urea has a high potential for soil acidification, influencing the values of exchangeable aluminum, potential acidity, and ∆pH, at layers of 0.00-0.20 and 0.20-0.40 m. The decrease in pH caused by increasing doses of N increased the density of positive electrical charges of the soil and reduced Mo content in the leaves of C. canephora by 67 %. The application of sodium molybdate via soil was efficient in providing Mo to Conilon coffee and provided a 3.7 % increase in the yield of processed coffee. Nevertheless, molybdic fertilization did not influence the Mo content in the soil in the evaluations carried out at the end of each production cycle.