ABSTRACT The objective of this study was to evaluate the growth and yield of okra as a function of phosphorus (P) doses and to obtain the critical leaf P content, under the edaphoclimatic conditions of Maranhão (MA), Brazil. The field experiment was carried out from February 15, 2017, to May 9, 2017, in São Luís, MA. The experimental design was randomized blocks, with four replications. The treatments were doses of 0, 80, 160, 240 and 320 kg ha-1 of P2O5, in the form of triple superphosphate, at planting, plus 10 t ha-1 of solid cattle manure. The increase of the P dose increased plant height, leaf dry mass and stem dry mass. With phosphorus supply, flowering occurred earlier than in plants without fertilization. Considering soils with low P content (P(resin) = 11 to 25 mg dm-3) and the minimum recommended organic fertilization for the okra crop of 10 t ha-1 of solid cattle manure, the maximum number of fruits, length of fruit and yield (9960.36 kg ha-1) were obtained with the fertilization of 80 kg ha-1 of P2O5, for the edaphoclimatic conditions of MA, Brazil. The critical leaf P content in okra is 3.4 g kg-1.

RESUMO O objetivo deste trabalho foi avaliar o crescimento e a produtividade do quiabo em função de doses de fósforo (P) e obter o teor crítico de P foliar, nas condições edafoclimáticas do Maranhão (MA), Brasil. O experimento de campo foi realizado no período de 15 de fevereiro de 2017 a 9 de maio de 2017, em São Luís, MA. O delineamento experimental foi de blocos casualizados, com quatro repetições. Os tratamentos foram doses de 0, 80, 160, 240 e 320 kg ha-1 de P2O5, na forma de superfosfato simples, no plantio, mais 10 t ha-1 de esterco bovino sólido. O aumento da dose de P aumentou a altura das plantas, massa seca de folhas e caule. Com o fornecimento de fósforo a precocidade do florescimento foi maior que em plantas não fertilizadas. . Considerando solos com baixo teor de P (P(resina) = 11 a 25 mg dm-3) e a adubação orgânica mínima recomendada para a cultura do quiabo de 10 t ha-1 de esterco bovino sólido, o número de frutos, comprimento do fruto e a produtividade máxima de frutos (9960.36 kg ha- 1) foram obtidos com a adubação de 80 kg ha-1 de P2O5, para as condições edafoclimáticas de MA, Brasil. O teor crítico foliar de P em quiabeiro é de 3,4 g kg-1.

ABSTRACT The intercropping is a production system that aims to provide increased yield with less environmental impact, due to greater efficiency in the use of natural resources and inputs involved in the production process. An experiment was carried out to evaluate the agronomic viability of kale and New Zealand spinach intercropping as a function of the spinach transplanting time. (0, 14, 28, 42, 56, 70, 84 and 98 days after transplanting of the kale). The total yield (TY) and yield per harvest (YH) of the kale in intercropping did not differ from those obtained in monoculture. The spinach TY was influenced by the transplanting time, the earlier the transplanting, the higher the TY. The spinach YH was not influenced by the transplanting time, but rather by the cultivation system. In intercropping, the spinach YH was 13.5% lower than in monoculture. The intercropping was agronomically feasible, since the land use efficiency index, which was not influenced by the transplanting time, had an average value of 1.71, indicating that the intercropping produced 71% more kale and spinach than the same area in monoculture. Competitiveness coefficient, aggressiveness and yield loss values showed that kale is the dominating species and spinach is the dominated.

The influence of plant population (31,250 and 46,875 plants ha-1) and nitrogen doses (0, 100, 200, and 300 kg ha-1) on the accumulation of macronutrients by cabbage plants was studied in Jaboticabal, Brazil, from February 18 to June 2, 2004. The experimental design was a randomized complete block in a 2 × 4 factorial scheme, with three replications. Differences in the amount of macronutrients accumulated by cabbage as function of N dose and plant population, were observed. The largest amounts of macronutrients were detected at the end of the plant cycle when the plant population was the lowest. The amounts of N, P, K, and S were not significantly different when the N dose was increased from 100 to 300 kg ha-1. The accumulated amounts of Ca and Mg were not significantly different when the N dose was increased from 200 to 300 kg ha-1. The decreasing sequence of macronutrient extraction (Ca, N, K, Mg, P, and S) was not altered by the treatments. The period from 40 to 60 days after transplantation was responsible for half of the macronutrient accumulation by the cabbage plants.

Con el fin de evaluar las interacciones entre las densidades de población (31250 y 46875 plantas ha-1) y el nitrógeno (0, 100, 200 y 300 kg ha-1) en la acumulación de macronutrientes en la col cv. 'Astrus', se realizó un experimento en Jaboticabal (Brasil) del 18 de febrero al 2 de junio de 2004. El diseño experimental fue de bloques al azar factorial 2 × 4 con tres repeticiones. Se observó diferencia en la cantidad de macronutrientes de la col en función de N y la densidad de población. Se observaron las mayores cantidades al final del ciclo con la menor densidad de la siembra, pero las cantidades de N, P, K y S no fueron diferentes cuando se utilizan de 100 a 300 kg ha-1 de N. Para Ca y Mg, las cantidades no fueron diferentes cuando se fertilizó con 200 o 300 kg ha-1 de N. La secuencia descendente de extracción de macronutrientes (Ca, N, K, Mg, P y S) no se vio afectada por los tratamientos. El período de 40 a 60 días después del trasplante fue responsable de la mitad de las cantidades acumuladas de macronutrientes en planta de la col.

Quatro experimentos foram conduzidos na Unesp, Brasil, com o objetivo de determinar a viabilidade agronômica de cultivos consorciados de alface e tomate em ambiente protegido. Consórcios estabelecidos por transplantes da alface aos 0, 10, 20 e 30 dias após o transplante (DAT) do tomate e de tomate aos 0, 10, 20 e 30 DAT da alface, foram avaliados em duas épocas e comparados às suas monoculturas. Cada experimento foi conduzido em delineamento de blocos ao acaso, com nove tratamentos. Verificou-se que a produtividade do tomate e a classificação dos frutos não foram influenciadas pela alface, mas a produção da alface foi menor em consórcio. Quanto mais atrasado o transplante da alface menor foi a sua produtividade. Houve efeito de época de cultivo sobre a dimensão da vantagem agronômica do consórcio sobre a monocultura. Na primeira época de cultivo, os consórcios estabelecidos com o transplante da alface de 30 dias antes e até 20 dias após o transplante do tomate proporcionaram índices de eficiência do uso da área (EUA) de 1,63 a 2,22. Na segunda época, os consórcios estabelecidos com o transplante da alface antes do tomate, em até 30 dias, proporcionaram índices EUA de 1,57 a 2,05.

Four experiments were carried out at the São Paulo State University, Brazil, with the aim of determining the agronomic viability of intercropping tomato and lettuce, under greenhouse conditions. The studied intercropping systems were established by transplanting lettuce at 0, 10, 20 and 30 days after transplanting (DAT) tomato and by transplanting tomato at 0, 10, 20 and 30 DAT lettuce. Intercropped tomato and lettuce were evaluated during two seasons and compared to their sole cropping. The experimental design was a randomized complete block with nine treatments. The productivity and the classification of the tomato fruits were not influenced by having lettuce intercropped with it, but lettuce production was lowered when tomato was intercropped with it. The longer the delay in lettuce transplanting, the greater the reduction in its productivity. There was an effect of cropping season on the extent of the agronomic advantage of intercropping over sole cropping. In the first cropping season, intercropping established by transplanting lettuce during the interval between 30 days before up to 20 DAT tomato yielded land use efficiency (LUE) indices of 1.63 to 2.22. In the second period, intercropping established with the transplanting of lettuce up to 30 days before tomato yielded LUE indices of 1.57 to 2.05.

At present, the Brazilian market prefers cabbage (Brassica oleracea var. capitata) of smaller size, which can be achieved by increasing population density; yet this management can alter the optimum rate of nitrogen (N), its second most required nutrient. This study was conducted in the Universidade Estadual Paulista, Jaboticabal, São Paulo, Brazil, from February to June 2004. The objective was to evaluate the effect of population density: 31 250 (D1) and 46 875 plants ha-1 (D2) with 0, 100, 200 and 300 kg N ha-1 on the growth and production of cabbage Astrus. The experimental design consisted of randomized blocks with a 2x 4 factorial arrangement and three replicates. Statistical analysis were a variance analysis (F test), the Tukey test for population density averages and polynomial regression for the N rates. In D1, an increase was recorded in the number of inner and outer leaves, dry matter of inner and outer leaves, the stem diameter at the insertion of the head, and the stem dry and fresh matter. The maximum size of the plant in D2 was 1.57 kg and was obtained with 300 kg N ha-1, while in D1 it was 2.1 kg and was obtained with 244 kg N ha-1. The optimal economic rate in D1 was 227.1 kg N ha-1. The highest yield (72.7 t ha-1) was obtained with the highest N rate in D2. Smaller cabbage heads, commercially preferred, were obtained without the application of N, regardless of plant population.

Actualmente, el mercado brasileño prefiere repollo (Brassica olerácea var. capitata) de menor tamaño, que puede conseguirse aumentando la densidad poblacional pero este manejo puede alterar la dosis óptima de nitrógeno (N), su segundo nutrimento más requerido. El presente estudio se realizó en la Universidad Estatal Paulista de Jaboticabal, São Paulo, Brasil, de febrero a junio de 2004. El objetivo fue evaluar el efecto de la densidad de población: 31 250 (D1) y 46 875 plantas ha-1 (D2) con 0, 100, 200 y 300 kg de N ha-1 en el crecimiento y producción de repollo Astrus. El diseño experimental fue de bloques al azar, con arreglo factorial 2x4, y tres repeticiones. Se realizó análisis de varianza (prueba de F), las medias de la densidad poblacional fueron analizadas con la prueba de Tukey y las dosis de N con regresión polinomial. En D1 aumentó, por planta, el número de hojas internas y externas, la materia seca de hojas internas y externas, el diámetro del tallo en la inserción de la cabeza, la materia seca y fresca del tallo. El máximo tamaño de la planta en D2 fue 1.57 kg obtenida con 300 kg de N ha-1, mientras que en D1 fue 2.1 kg y se obtuvo con 244 kg de N ha-1. La dosis óptima económica en D1 fue 227.1 kg de N ha-1. La mayor producción (72.7 t ha-1) se obtuvo con la dosis de N más alta en D2. Cabezas menores de repollo, preferidas comercialmente, se obtuvieron sin la aplicación de N, independientemente de la población de plantas.

A presença de inibidores de germinação no fruto da beterraba pode comprometer o estande da cultura. O presente trabalho objetivou avaliar a interferência do período de imersão em água corrente no desempenho fisiológico das sementes de beterraba. Para tanto, sementes da cultivar Top Tall Early Wonder foram submetidas à ação de água corrente durante 0 (testemunha), 1; 1,5; 2; 3; 4; 5 e 6 horas, secadas e avaliadas pelo teste de germinação. A lavagem por duas horas foi suficiente para aumentar a germinação das sementes.

The presence of germination inhibitors in the fruit of beetroot can reduce the stand of crop. The present work aimed to evaluate the interference of immersion period in running water in the physiological performance of the beetroot seeds. Seeds from cultivar Top Tall Early Wonder were submitted to the action of running water during 0 (control), 1; 1,5; 2; 3; 4; 5 and 6 hours, dried and physiologically evaluated using germination test. Washing the seeds during two hours was enough to increase the germination.

Embora seja reconhecida como planta típica de clima temperado, a alface possui cultivares melhoradas geneticamente com maior tolerância às temperaturas elevadas, o que possibilita seu cultivo todo o ano. Objetivou-se, com o presente trabalho, avaliar a produção de seis cultivares de alface do grupo americana, cultivadas no solo e em hidroponia, nas estações de inverno e verão. Os experimentos foram conduzidos em casa de vegetação, na UNESP, Jaboticabal, SP. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições. A produção de massa fresca e seca da parte aérea das cultivares estudadas foi influenciada pela época (inverno ou verão) mas não o foi pelo sistema de cultivo (solo ou hidroponia). O cultivo de verão determinou redução de 28% no acúmulo de massa fresca, constituindo-se em época marginal à produção de alface em Jaboticabal, SP, considerando-se os sistemas de cultivo empregados.

Lettuce as known a typical plant of temperate climate-Some genetically improved lettuce cultivars have tolerance to high temperature and make its cultivation possible through out the year. The present work had the aim to evaluate the yield of six cultivars from creasp head group, produced in soil and in hydroponics system in winter and summer seasons. The experiments were conducted under protected ambient, at UNESP, Jaboticabal, SP. The experimental design was a randomized blocks with three replications. The fresh and dry mass of aerial part were influenced by planting time (winter or summer) but not by crop system (soil and hydropony). Summer season reduced yield by 28% on fresh mass.

O trabalho foi realizado para verificar se cultivos consorciados de alface e de rabanete são economicamente viáveis. Foram elaborados os custos de produção das culturas em monocultivo e em consorciação. Alguns indicadores agroeconômicos foram usados para avaliar a eficiência dos sistemas consorciados: índice de uso eficiente da terra, receita bruta, receita líquida, vantagem monetária, vantagem monetária corrigida, taxa de retorno e índice de lucratividade. A associação das culturas da alface e rabanete permitiu um melhor aproveitamento dos fatores de produção, com aumento na produção por unidade de área. Os consórcios estabelecidos ao zero (espaçamento entrelinha 0,30 x 0,30 m) e aos 14 dias após o transplantio da alface (espaçamento entrelinhas de 0,40 x 0,30m) tiveram os melhores indicadores agroeconômicos, com índices de uso eficiente da terra de 1,76 e 1,61, taxas de retorno de 4,13 e 4,53, e índices de lucratividade de 75,77 e 77,94%, respectivamente.

Our aim was to verify if intercropping systems of crisphead lettuce and radish were economically viable. The costs of production of the cultures were evaluated in monoculture and in intercropping. Some agrieconomic indicators were used to evaluate the efficiency of the systems such as the appropriate use of the land gross and net revenue, monetary advantage, corrected monetary advantage, rate of return and profit margin were used to evaluated the efficiency of intercropping systems. The association of the lettuce and radish allowed a better use of the production factors, with increase in the production per unit of area. The intercropping systems established in 0 (spacing between rows of 0.30 x 0.30 m) and to 14 (spacing between rows of 0.40 x 0.30 m) days after the transplant of crisphead lettuce presented the best agrieconomics indicators, with land equivalent ratios of 1.76 and 1.61, rates of return of 4.13 and 4.53, and profit margins of 75.77% and 77.94%, respectively.

Com o objetivo de determinar o acúmulo e a exportação de macronutrientes em melancia sem sementes, híbrido Nova, conduziu-se um experimento em Itápolis (SP), de outubro a dezembro de 2001, em um ARGISSOLO VERMELHO-AMARELO Distrófico. As amostragens de plantas foram realizadas aos 15; 30; 45; 60 e 70 dias após transplantio (DAT), sendo quantificados o acúmulo de massa seca e de macronutrientes na folha, caule + ramos e frutos. O acúmulo de peso seco foi lento até 30 DAT, intensificando-se a partir deste, alcançando no final do ciclo o total de 545,1 g planta-1, onde as folhas participaram com 30%, caule + ramos com 31% e os frutos com 39%. Até 30 DAT, o acúmulo de nutrientes também foi pequeno, sendo que com a frutificação, houve um forte incremento na quantidade de nutrientes acumulados, com maior demanda no período de 45 a 60 DAT. A ordem decrescente dos macronutrientes acumulados pela cultura foi: K>N>Ca>P>Mg>S. Os frutos exportaram 20,3 kg ha-1 de N; 4,0 kg ha-1 de P; 26,6 kg ha-1 de K; 1,4 kg ha-1 de Ca; 1,6 kg ha-1 de Mg e 1,4 kg ha-1 de S.

The accumulation and exportation of nutrients of the seedless watermelon hybrid Nova was determined under field conditions. The experiment was carried out in Typic Paleudult soil, in the Itápolis region, São Paulo State, Brazil. Sampling of the plants was done at 15; 30; 45; 60 and 70 days after transplanting date (DAT) and the accumulation of dry mass and macronutrients was quantified in leaves, stem + branches and fruits. The dry mass accumulation was slow until 30 DAT, intensifying with the beginning of the fruit development. At the end of the cycle, the average contribution of leaves, stems + branches and fruits, was respectively of 30; 31 and 39%. The accumulation of nutrients followed the curve of dry mass accumulation. The larger demand for macronutrients occurred from 45 to 60 DAT. The order of nutrients accumulation for the culture was: K>N>Ca>P>Mg>S. The fruits exported 20.3 kg ha-1 of N, 4.0 kg ha-1 of P, 26.6 kg ha-1 of K, 1.4 kg ha-1 of Ca, 1.6 kg ha-1 of Mg and 1.4 kg ha-1 of S.

Foram conduzidos dois experimentos em propriedades rurais, localizadas próxima a cidade de Borborema (SP), de outubro a dezembro/2001 e de fevereiro a abril/2002, com o objetivo de determinar as quantidades exportadas de nutrientes pelos frutos de melancia, em função de fontes e doses de potássio, em duas épocas de cultivo. O delineamento experimental utilizado foi o de blocos casualizados completos, em esquema fatorial 3x4, com três repetições, sendo avaliados as fontes: cloreto, nitrato e sulfato de potássio e as doses: 50; 100; 200 e 300 kg ha-1 de K2O. Com exceção do Mg, as maiores exportações de nutrientes pelos frutos foram obtidas no cultivo de outubro a dezembro. A massa seca e as exportações de N, P, K, e Ca aumentaram de forma quadrática com as doses de potássio. A aplicação KCl aumentou respectivamente, de forma quadrática e linear, as exportações de S e Cl pelos frutos de melancia.

Two field experiments were conducted in Borborema, São Paulo State, Brazil, from October to December 2001 and February to April 2002, to evaluate the nutrients recruitment of watermelon fruits, Tide hybrid, as a result of potassium sources and doses. The experimental design was a randomized complete block, with three replications, in 3x4 factorial scheme, the sources being evaluated: potassium chloride, nitrate and sulphate and doses of 50; 100; 200 and 300 kg ha-1 K2O. Greater recruitment of N, P, K, Ca, S and Cl by watermelon fruits was obtained in the first trial, while the recruitment of Mg was observed in the second trial. The dry mass and recruitment of N, P, K, and Ca increased with potassium doses. S and Cl of the watermelon fruits increased with the increase of KCl doses in a quadratic and linear form, respectively.

O trabalho foi conduzido em casa de vegetação, da UNESP em Jaboticabal, de maio a junho de 2001, com o objetivo de avaliar o desempenho da rúcula, cultivar Cultivada, sob diferentes concentrações de cobre na solução nutritiva, em cultivo hidropônico. O delineamento utilizado foi inteiramente casualizado com quatro repetições e quatro tratamentos: 0; 0,036; 0,072 e 0,108 mgL-1 de Cu adicionado à solução nutritiva, na forma de sulfato de cobre. Após 30 dias do transplantio, 150 plantas foram colhidas ao acaso em cada parcela, para análise da matéria seca e dos teores de Cu, Fe, Zn e Mn na parte aérea das plantas. Foi observado sintoma visual de deficiência de Cu apenas no tratamento sem adição de cobre, com forte redução no tamanho das plantas. A produção de matéria seca da parte aérea foi significativamente influenciada pelo aumento das concentrações de Cu. A máxima produção e 95% da máxima foram obtidas, respectivamente, com 0,108 mgL-1 e 0,064 mgL-1 de cobre. Os teores de Cu e Mn na parte aérea aumentaram com as concentrações de Cu na solução nutritiva.

The response of roquette cv. Cultivada, to different copper concentrations in the nutrient solution was evaluated. The experimental design was completely randomized, with four treatments (0; 0.036; 0.072 and 0.108 mgL-1 of copper added to the nutrient solution) and four replications. 30 days after transplanting, 150 plants were collected at random in order to analyse the concentrations of Cu, Fe, Zn and Mn in the dry matter of the aerial part. Symptoms of deficiency were observed in the treatment without copper, presenting strong reduction in the plant size. The dry matter yield was significantly influenced by the increasing concentrations of Cu, with maximum production and 95% of maximum yield was obtained respectively with 0.108 and 0.064 mgL-1 of Cu in the nutritive solution. The concentration of Cu and Mn in the aerial part increased with increasing concentration of Cu in the nutritious solution.