ABSTRACT. As the fourth largest importer of olive oil and the fifth largest importer of olives, Brazil is one of the largest importers of olive (Olea europaea L.) products in the world. In recent decades, the introduction and growth of olive cultivars with lower chilling requirements in the south and southeast regions of Brazil have made olive production viable in the country. However, there is a dearth of information about the management of olive crops in Brazil, especially in relation to studies about the nutritional needs of olive trees grown in subtropical regions, which may enable advances in the productivity of this fruit. The aim of this study was to evaluate the growth, dry matter production and nutritional status of the olive tree under the effect of nutrient omissions, as well as to establish visual diagnostic parameters of nutrient deficiencies. We used a completely randomized design with ten treatments and three replicates grown in the Hoagland-Arnon nutrient solution and solutions with individual omissions of N, P, K, Ca, Mg, S, B, Fe, and Zn. The treatments that most limited the growth of olive trees were the N, Ca, and B omission treatments.

RESUMO Objetivou-se avaliar as características externas e as do suco de lima-ácida ‘Tahiti’, produzida sob adubação nitrogenada e potássica. Utilizou-se o delineamento inteiramente casualizado, com três repetições de quatro frutos das duas plantas centrais, em esquema fatorial 4 x 5, sendo quatro doses de N (0; 25; 50 e 100 Kg. ha-1. ano-1) e cinco doses de K2O (0; 25; 50; 100 e 200 kg. ha-1. ano-1), totalizando 20 tratamentos. Em pós-colheita, avaliaram-se as características externas (tamanho, cor e espessura da casca, firmeza e massa fresca) e as do suco (volume, percentagem, sólidos solúveis, índice tecnológico, pH, acidez titulável, ratio e ácido ascórbico dos frutos). O tamanho, a cor da casca, o teor de sólidos solúveis e o pH do suco de lima ácida ‘Tahiti’ não foram influenciados pelas adubações com N e K2O. A espessura da casca, a porcentagem de suco e o índice tecnológico aumentaram com as doses de N e K2O aplicadas no solo. O volume de suco e a firmeza do fruto reduziram com as aplicações das doses de K2O. A acidez titulável e o teor de ácido ascórbico aumentaram com as doses de K2O. As diferentes doses de adubação nitrogenada e potássica influenciaram mais na qualidade do suco que nas características externas de lima-ácida ‘Tahiti’, em pós-colheita.

ABSTRACT This study aimed to evaluate external characteristics and juice obtained from ‘Tahiti’ acid lime produced under nitrogen and potassium fertilization. This study had a completely randomized design with three replicates of four fruits of the two central plants, 4 x 5 factorial and four N doses (0, 25, 50 and 100 Kg ha-1 year- 1) and five K2O doses (0, 25, 50, 100 and 200 Kg ha-1 year- 1), totaling 20 treatments. In the postharvest period, external characteristics (size, color and skin thickness, firmness and fresh mass) and juice (content, percentage, soluble solids, technological index, pH, titratable acidity, ratio and ascorbic acid) of fruits were evaluated. Size, skin color, soluble solids content and pH of ‘Tahiti’ acid lime juice were not affected by N and K2O fertilization. Skin thickness, juice percentage and technological index increased with the N and K2O doses applied to the soil. Juice content and fruit firmness decreased with application of K2O doses. Titratable acidity and ascorbic acid content increased with K2O doses. The different nitrogen and potassium doses influenced more the juice quality than the external characteristics of ‘Tahiti’ acid lime in the postharvest period.

Resumo: O objetivo deste trabalho foi estimar as doses de nitrogênio e potássio, para obter a máxima eficiência técnica e econômica e os níveis críticos destes dois nutrientes, em folhas de limão 'Tahiti' irrigado, cultivado em Neossolo Quartzarênico, em cinco safras. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições, em arranjo fatorial 4x5, com quatro doses de N (0, 25, 50 e 100 kg ha-1) e cinco doses de K2O (0, 25, 50, 100 e 200 kg ha-1). As doses estimadas para alcançar a máxima eficiência técnica foram 90, 99, 69, 66 e 100 kg ha-1 de N e, para a máxima eficiência econômica, 85, 95, 67, 64 e 93 kg ha-1 de N, para a primeira, a segunda, a terceira, a quarta e a quinta safra, respectivamente. As doses de K2O para obter a máxima eficiência técnica foram 126, 116, 101, 98 e 95 kg ha-1 e, para a máxima eficiência econômica, 112, 105, 94, 90 e 88 kg ha-1 de K2O, para a primeira, segunda, terceira, quarta e quinta safra, respectivamente. Os níveis críticos foliares médios estimados são de 25 g kg-1 de N e 22 g kg-1 de K para as cinco safras.

Abstract: The objective of this work was to estimate nitrogen and potassium rates, in order to obtain maximum technical and economic efficiency and the critical levels of these two nutrients on leaves of irrigated 'Tahiti' lime tree, grown in a Typic Quartzipsamment soil in five crop seasons. A randomized complete block design was carried out with four replicates, in a 4x5 factorial arrangement, with four N rates (0, 25, 50, and 100 kg ha-1) and five K2O rates (0, 25, 50, 100, and 200 kg ha-1). The estimated rates to achieve the maximum technical efficiency were 90, 99, 69, 66, and 100 kg ha-1 N, and for the maximum economic efficiency, 85, 95, 67, 64, and 93 kg ha-1 N, for the first, second, third, fourth, and fifth crop seasons, respectively. The rates of K2O to obtain the maximum technical efficiency were 126, 116, 101, 98, and 95 kg ha-1, and for maximum economic efficiency, 112, 105, 94, 90, and 88 kg ha-1 K2O, respectively, for the first, second, third, fourth, and fifth crops. The average, estimated critical levels for leaf contents are 25 g kg -1 N and 22 g kg -1 K, in five crop seasons.

RESUMO As áreas produtivas com amoreira-preta vêm se ampliando nas regiões subtropicais brasileiras, mas ainda há necessidade de se aprimorar o manejo cultural, principalmente no tocante às suas necessidades nutricionais, bem como estabelecer parâmetros de diagnose visual de deficiência, o que possibilitaria alcançar maiores produtividades. Objetivou-se avaliar a deficiência visual e a composição mineral de amoreirapreta sob o efeito da omissão de nutrientes. O experimento foi desenvolvido em delineamento em blocos inteiramente casualizados, com nove tratamentos e três repetições, que corresponderam ao cultivo em solução nutritiva de Hoagland & Arnon completa e solução com omissão individual de N, P, K, Ca, Mg, S, Fe e B. Avaliou-se a produção de matéria seca e composição química da parte aérea e sistema radicular, bem como a diagnose visual.As deficiências dos nutrientes nas mudas de amoreira-preta se traduziram por sintomas típicos, enquanto, no tratamento sem restrição de nutrientes, os teores nutricionais obtidos respectivamente nas folhas e raízes foram N = 11,4 g kg-1 e 16,1 g kg-1; P = 1,3 g kg-1 e 4,2 g kg-1; K = 9,8 g kg-1 e 13,2 g kg-1; Ca = 5,7 g kg-1e 9,8 g kg-1; Mg = 2,3 g kg-1e 2,6 g kg-1; S = 1,4 g kg-1 e 2,7 g kg-1; B = 37,8 mg kg-1 e 18,9 mg kg-1; Fe = 119,9 mg kg-1 e 1.603,9 mg kg-1. As omissões individuais de N, Ca e B foram as mais limitantes para o crescimento vegetativo dessa espécie.

ABSTRACT The areas planted with blackberry trees have expanded in Brazilian subtropical regions, but is still necessary to improve the crop management, especially regarding its nutritional needs, as well as establishing parameters of visual diagnosis of deficiency, what would allow to achieve higher yields. This study aimed to evaluate the visual deficiency and mineral composition of blackberry tree under omission effect of nutrients. The experimental design was completely randomized blocks, with nine treatments and three replications, corresponding to the cultivation in a complete Hoagland & Arnon’s nutritive solution and in a solution with individual omission of N, P, K, Ca, Mg, S, Fe and B. The dry matter and chemical composition of shoot and root were evaluated, as well as the visual diagnosis. The nutrient deficiencies in seedlings of blackberry trees were pointed out by typical symptoms, while in the treatment with no nutrients restriction the nutritional contents found respectively in the leaves and roots were N = 11.4 g kg-1 and 16.1 g kg-1; P = 1.3 g kg-1 and 4.2 g kg-1; K = 9.8 g kg-1 and 13.2 g kg-1; Ca = 5.7 g kg-1 and 9.8 g kg-1; Mg = 2.3 g kg-1 and 2.6 g kg-1; S = 1.4 g kg-1 and 2.7 g kg-1; B = 37.8 mg kg-1 and 18.9 mg kg-1; Fe = 119.9 mg kg-1 and 1,603.9 mg kg-1. Individual omissions of N, Ca and B were the most limiting ones for the vegetative growth of this species.

The objective of this study was to evaluate the effects of nitrogen (N) fertilization in the four seasons of the year on forage production, nitrate (NO3) in the sap, total N in the forage and relative chlorophyll index (SPAD reading) in the leaves of irrigated Panicum maximum cv. Tanzania grass, establishing their critical ranges. In addition, we evaluated the ability to predict forage production based on NO3 in the sap, total N in the forage and relative chlorophyll index. The soil in the experimental area was classified as an Oxisol (Red-Yellow Latosol) with a clayey texture. Annual rates of N (0, 200, 400 and 800 kg ha-1) in the form of urea were the treatments tested. Irrigation was performed through a conventional spray system. The NO3 content in the sap and the relative chlorophyll index were measured in leaves using a portable meter with NO3 selective electrode and the SPAD-502 portable chlorophyll meter device, respectively. Tanzania guinea grass was very responsive to N fertilization, except in the winter. The critical ranges of the SPAD reading proved to be more adequate for monitoring the nutritional state of N of Tanzania guinea grass in the different seasons of the year than the NO3content in the sap and the total N content in the dry matter. Use of the chlorophyll meter is more advantageous than the use of the portable meter with an nitrate selective electrode for predicting the nutritional status of Tanzania guinea grass.

To apply high amounts of K to the soil there must be adequate quantities of Mg, thus avoiding the rise of physiological disorders in the banana plant which appear as Mg-induced deficiency symptoms. The purpose of this study was to evaluate the effects of application of K and Mg on the vegetative development and yield of the banana cv. "Prata Anã'. Treatments were distributed in a randomized block design in a 3 x 5 factorial arrangement, corresponding to three doses of potassium (0, 800 and 1200 kg ha-1 year-1) and five doses of magnesium (0, 60, 120, 240 and 480 kg ha-1 year-1), with three replicates. The sources of potassium and magnesium were potassium chloride and magnesium sulfate, respectively. Application of K, regardless of the cycle, increased the bunch weight, the number of banana fruits per bunch, the number of hands per bunch, and the weight and diameter of the middle fruit of the banana plant. Increasing doses of Mg applied to the soil reduced the weight of the bunch in the first cycle; and with increasing doses of K there was an increase in the leaf content of K and Ca, with a decrease in the leaf content of Mg and B in the banana cv. 'Prata Anã'.

Para que sean aplicadas grandes cantidades de K en el suelo, hay necesidad que los niveles de Mg sean adecuados en lo mismo, evitando así la aparición de desórdenes fisiológicos en el banano, expresado en los síntomas de deficiencia inducida de Mg. El objetivo de este estudio fue evaluar los efectos de la aplicación de K y Mg en el desarrollo y la productividad del banano'Prata Anã'. Los tratamientos se dispusieron en un diseño de bloques al azar con un factorial 3 x 5, que corresponden a tres niveles de potasio (0, 800 y 1200 kg ha-1 año-1) y cinco dosis de magnesio (0, 60, 120, 240 y 480 kg ha-1 año-1), con tres repeticiones. Las fuentes de potasio y magnesio fueron, respectivamente, cloruro de potasio y sulfato de magnesio. La aplicación de K, independiente del ciclo, aumentó el peso del racimo, número de frutos por racimo, el número de manos por racimo, la masa y el diámetro del fruto central de la banana. Dosis crecientes de Mg aplicadas al suelo reducen la masa del racimo en el primer ciclo. Con el incremento de las dosis de K hubo un aumento en K y Ca foliar, con una reducción en Mg y B foliar del banano 'Prata Anã'.

Para aplicar elevada quantidade de K no solo, é necessário que exista Mg em quantidade adequada, para evitar o aparecimento de distúrbios fisiológicos na bananeira. O objetivo deste trabalho foi avaliar os efeitos da aplicação de potássio (K), magnésio (Mg) e calcário sobre o desenvolvimento de mudas de bananeira 'Prata-anã' (AAB) cultivadas em casa de vegetação. Os tratamentos foram distribuídos no delineamento de blocos casualizados, com quatro repetições em esquema fatorial (5x5x2), correspondentes a cinco doses de K (0; 200; 400; 800 e 1.600 mg dm-3), cinco doses de Mg (0; 30; 60; 90 e 180 mg dm-3) e duas doses de calcário dolomítico (0 e 2 t ha-1). A produção da massa da matéria seca das mudas de bananeira aumentou com as aplicações de K e calcário no solo e reduziu com as doses de Mg. Para a produção máxima da massa da matéria seca da parte aérea das mudas de bananeira, a relação Ca: K: Mg no solo apresentou valores de 2,0: 0,3: 0,9, que correspondem a 62%, 9% e 28% da saturação por base, respectivamente.

To apply high amount of K in the soil, it is necessary that Mg in adequate amount exists, in order to prevent the appearance of physiologic disturbances in banana tree. The objective of this work was to verify the effects of the application of K, Mg and limestone in the development of banana tree seedlings 'Prata Anã'(AAB) cultivated in greenhouse. The treatments were distributed in a complete block design, with four repetitions, in factorial scheme (5x5x2), corresponding to five K rates (0, 200, 400, 800 and 1600 mg dm-3), five Mg rates (0, 30, 60, 90 and 180 mg dm-3) and two limestone rates (0 and 2 t ha-1). The dry matter production of banana tree seedlings increased with the applications of K and limestone in soil and reduced with the rates of Mg. For the maximum production of dry matter of the aerial part of the banana tree seedlings the relationships Ca: K: Mg in the soil presented values of 2,0: 0,3: 0,9, that correspond to 62%, 9% and 28% of the saturation for base, respectively.