Nivaldo Duarte Costa

Níveis de nitrogênio por fertirrigação e densidade de plantio na cultura do melão em um Vertissolo

O trabalho constou de um experimento com melao (Cucumis melo L.), conduzido em um Vertissolo, em Juazeiro, BA, em 1995, com o objetivo de avaliar o efeito de niveis de N por fertirrigacao e de densidades de plantio na produtividade e qualidade de fruto. Os niveis de N foram 0, 80, 130 e 180 kg/ha, combinados com os espacamentos 2,00 e 1,80 m entre linhas e 0,20 m entre plantas, com uma ou duas plantas por cova. A fonte de N foi a ureia, aplicada diariamente ate 42 dias apos a germinacao, por meio da irrigacao por gotejamento. Todos os tratamentos receberam uma adubacao uniforme de 120 kg/ha de P2O5 e 120 kg/ha de K2 O. Os espacamentos entre linhas nao causaram diferencas significativas em nenhuma variavel estudada. O nivel de 80 kg/ha de N combinado com uma planta por cova proporcionou uma produtividade de 34,07 t/ha, com 55,7% de frutos proprios para o mercado interno, nao-significativamente (P £ 0,05) inferior a produtividade obtida com os niveis mais elevados de N em qualquer combinacao. Com este mesmo nivel, obtiveram-se frutos com 10,22o Brix significativamente (P£ 0,05) superior ao do tratamento sem N e nao-significativamente inferior ao dos outros niveis. Para se obter uma maior parte de frutos proprios para o mercado externo, foi necessario elevar a densidade para duas plantas por cova e o nivel de N para 130 ou 180 kg/ha. O peso medio dos frutos aumentou de 1,008 para 1,705 kg, a medida que foram aumentados os niveis de N ou se diminuiu a densidade de plantio de duas para uma planta por cova.This study consisted of one experiment with melon (Cucumis melo L.), carried out in a Vertisol in Juazeiro, BA, Brazil, in 1995, with the objective of evaluating the effects of nitrogen levels through fertirrigation and plant density on fruit yield and quality. The N levels were 0, 80, 130 and 180 kg/ha, combined with row spacings of 2.0 and 1.8 m and 0.20 m between plants within the row, with one or two plants/hole. The source of N was urea applied daily up to 42 days after germination, through drip irrigation. All treatments had a uniform fertilization of 120 kg/ha of P2O5 and 120 kg/ha of K2O. No significant difference was caused by spacing between rows in the studied variables. Eighty kg/ha of N combined with one plant per hole gave a yield of 34.07 ton/ha, being 55,7% of fruit allocated to inside market, not significantly lower than those obtained with the highest N levels in any combination. This same N level gave fruits with 10.22o Brix, significantly higher than the treatment without N and not significantly lower than the other levels. In order to get high number of good fruit for out side market it was necessary to elevate the density to two plants per hole and N level to 130 or 180 kg/ha. Mean weight of fruits increased from 1.008 to 1.705 kg with the increase in the levels of N and the decrease in plant density of two plants per hole to one plant per hole.

Desafios e oportunidades para o agronegócio da cebola no Brasil

The challenges and the oportunities for the onion agribusiness The main objective of this work was to describe some socieconomic aspects of the onion production in Brazil and to detect the principal challenges and opportunities for the onion agribusiness. The onion cultivation in Brazil is a family activity (88%), generating about 250 thousand jobs directly involved in the production. The onion consumption in Brazil is nearly 85 thousand t per month. With the consolidation of the MERCOSUL, the onion import from Argentina and the national production has caused excess of supply in some months, generating losses and consequent damages for the producers. The Brazilian productive sector needs to improve the technological level of the onion production to reach greater technical and economic efficiency. However, it is necessary that Brazilian and Argentinian producers look for a better production forecast to avoid excess of supply during some periods of the year.

Fontes de fósforo aplicadas na cultura do melão via água de irrigação

This study was carried out with the objective of evaluating the effect of three phosphorus sources applied conventionally and through trickle irrigation on melon crop (Cucumis melo L.), hybrid AF-682. The sources of phosphorus were simple superphosphate, monoammonium phosphate (MAP) and phosphoric acid applied up to 30 and 42 days after germination through trickle irrigation and conventionally. The experiment was conducted in a completely randomized block design, with four replications. All the treatments had the same amount of phosphorus (120 kg ha-1 of P2O5) according to soil analysis. The highest commercial fruit yields were obtained with phosphoric acid applied through trickle irrigation up to 30 and 42 days after germination (28.90 and 32.20 t ha-1, respectively), not differing from MAP applied through trickle irrigation up to 42 days after germination (27.95 t ha-1). The sources of phosphorus and modes of application did not influence the mean weight of fruits (1.43 kg), 65% of fruits being of type 8 to 10; however differences were observed in the soluble solids content at harvest time, highest content (brix 12.53o) was obtained in phosphoric acid treatment.

Avaliação de cultivares de cebola em Petrolina-PE

With the objective of identifying high productive and better quality onion cultivars for the tropical semi-arid region of Brazil, field trials were conducted at Petrolina, Pernambuco State, Brazil, from February until July of 1996.The experimental design was a randomized complete blocks with four repetitions and twenty treatments (Cultivars Granex-429, Texas Grano-PRR, Brownsville, Houston, Texas Grano-502, Texas Grano-438, Conquista, Composto IPA-6, Belem IPA-9, Franciscana IPA-10, Valeouro IPA-11, Alfa Tropical (CNPH-6179), CNPH-5898, CNPH-6074, CNPH-6040, CNPH-6067, Bola P. Empasc, XP-1, XP-2 and Crioula Mercosul). Production of commercial bulbs ranged forms 21.41 to 61.78 ton/ha. Texas Grano-PRR had the highest yield (61.78 ton/ha), followed by Granex-429 (58.28 ton/ha), Texas Grano-438 (56.97 ton/ha), Brownsville (55.38 ton/ha), Texas Grano-502 (53.97 ton/ha) and Houston (53.35 ton/ha).

Produtividade e qualidade pós-colheita de cebola adubada com doses crescentes de nitrogênio e potássio

This study was carried out from March to September 2000, in Petrolina, Pe rnambuco State, Brazil, to evaluate the influence of nitrogen and potassium levels on yield characteristics and post-harvest quality of onion bulbs (Allium cepa L.). The cultivar Franciscana IPA-10 was used. The experimental design was a randomized complete block in a 4 x 3 factorial scheme, involving four levels of nitrogen (0; 60; 120 and 180 kg ha-1) and three levels of potassium (0; 90 and 180 kg ha-1) with three replications. The commercial yield showed a linear effect in the absence of potassium fertilization, while the levels of 90 and 180 kg ha-1 of potassium provided maximum yield with the levels of 175.8 and 169.4 kg ha-1 of nitrogen. Increasing the doses of nitrogen resulted in a reduction of the non-commercial yield (culls). In the absence of potassium fertilization, a linear effect was obtained as a result of the levels of nitrogen for fresh mass of the bulb. For the levels of 90 to 180 kg ha-1 of potassium, the highest yield of fresh mass of the bulb was obtained with the level of 153.3 kg ha-1 of nitrogen. The levels of nitrogen influenced the classification of commercial bulbs of onion and the largest percentage of bulbs of the class 3 (85,8%) corresponded the dose of 153,6 kg ha-1 of nitrogen. No significant mass loss occurred after 20 days and only after 40 and 60 days after cure did any significant effects become evident and there was no interaction between the levels of nitrogen and potassium.

Características produtivas da melancia em diferentes espaçamentos de plantio

Diferentes espacamentos de plantio foram avaliados na producao de melancia em experimento da Embrapa Semi-Arido em Petrolina, de outubro a dezembro de 1998. Utilizou-se o delineamento experimental de blocos ao acaso em esquema fatorial 2 x 3, consistindo de dois espacamentos entre linhas (2,50 e 3,00 m) e tres espacamentos entre plantas (0,40; 0,60 e 0,80 m) e 3 repeticoes, sendo utilizada a cultivar Crimson Sweet. O espacamento entre linhas de 3,00 m apresentou maior producao (42,46 t/ha), sendo que entre plantas os espacamentos de 0,60 e 0,80 m alcancaram as maiores producoes com 42,50 e 45,29 t/ha, respectivamente, nao mostrando diferencas entre si. Nao foram verificadas diferencas significativas para producao de frutos refugo nos espacamentos entre linhas. No entanto, o menor espacamento entre plantas proporcionou maior producao com 20,21 t/ha, seguido pelos espacamentos de 0,60 m (12,86 t/ha) e 0,80 m (8,62 t/ha). O incremento dos espacamentos, tanto entre linhas como entre plantas, resultou em frutos de maior tamanho, tendo o espacamento 3,00 x 0,80 m apresentado a maior massa fresca do fruto (8,83 kg/fruto). O maior numero de frutos por planta (1,35 frutos) foi obtido com o espacamento de 3,00 x 0,80 m.

Desempenho de cultivares de cebola em cultivo orgânico e tipos de solo no Vale do São Francisco

In this research were evaluated the yield of onion cultivars under organic growth in the Sao Francisco Valley. Two field trials were evaluated, one at the Experimental Farm Station of Embrapa Tropical Semi-Arid, in Petrolina, in an ultisol type and the other at the Experimental Farm Station of Mandacaru, in Juazeiro, in a vertisol type, from February to October of 2005. The experimental design was of randomized complete blocks, with 18 and 14 cultivars, respectively, and four replications. In the ultisol, the total yield of bulbs ranged from 13.52 to 39.52 t/ha. The commercial yield ranged from 7.45 to 38.32 t/ha where the cultivars Brisa (38.32 t/ha) and Sao Paulo (35.86 t/ha) showed the highest yield without statistical difference; Cultivars Botucatu-150 (26.41 t/ha) and Pira Ouro (26.37 t/ha) also stood out with high yield without statistical difference. The cultivars Conquista (7.45 t/ha) and Crioula Alto Vale (7.81 t/ha) presented the worst performance. In the vertisol the total yield of bulbs ranged from 6.87 to 24.68 t/ha. The cultivars Texas Grano PRR (21.56 t/ha) and IPA-10 (17.50 t/ha) presented the highest yield, without statistical differences. The cultivars Crioula Alto Vale, CNPH-6348, CNPH-6436 and CNPH- 6206 presented no commercial yield.

Produção e qualidade de melão influenciados por matéria orgânica, nitrogênio e micronutrientes

The effects of nitrogen, boron, molybdenum and zinc applied as fertigation, and cattle manure applied to the soil, were evaluated on the yield and quality of melon (Cucumis melo) in two types of soils of the Submedio Sao Francisco River Valley, Brazil. Six experiments were carried out in 1998, 1999 and 2000, three being in a red yellow Latosoil in Petrolina, and three in a Vertisoil, in Juazeiro, in a randomized complete block design with four replications and nine treatments, as follows: 1. N1; 2. N2; 3. N3; 4. N1 + C.M.; 5. N2 + C.M.; 6. N2 + B + Mo + Zn; 7. N2 + B + Mo; 8. N2 + B + Zn, and 9. N2 + Mo + Zn, where N1, N2 and N3 represent, respectively, 0 or 30, 80 and 160 kg/ha of N; C.M. was 20 m3 ha-1 of manure; B = 1.1 kg ha-1; Mo = 0.4 kg ha-1, and Zn = 4 kg ha-1. Nitrogen and the micronutrients were applied through irrigation water. Melon yield showed response to nitrogen in the Latosoil in 1998 and in 2000, and in the Vertisoil in 1999. Higher significant yields were obtained with 80 kg ha-1 of N, varying among experiments from 32.0 to 40.2 t ha-1. Cattle manure caused significant increase only in yield in 1998 and in mean fruit weight in 2000 in the Vertisoil. Soluble solid contents in fruits increased with nitrogen application in the Latosoil in 2000. The micronutrients did not have significant effect on yield. In two years, mean fruit weight was higher in Vertisoil than in Latosoil.

Efeito de fertilizantes nitrogenados na produtividade de melão

A study was carried at Petrolina-PE, Brazil, with the melon crop (Cucumis melo L.), cv. Valenciano Amarelo, in a Red-Yellow Latosol with the objective of evaluating the effect of nitrogen fertilizers sources and their combinations, applied through the conventional way and through water irrigation during the crop cycle. The experimental design was a split block with four replica- tions and nine treatments: 1. control (without N); 2. urea; 3. ammonium sulphate, both applied con- ventionally; 4. urea applied up to 42 days after germination; 5. ammonium sulphate applied up to 42 days after germination; 6. urea applied up to 15 days and potassium nitrate from 16 to 42 days after germination; 7. urea applied up to 15 days and ammonium sulphate from 16 to 42 days; 8. urea applied up to 30 days and potassium nitrate from 31 to 42 days, and 9. urea applied up to 15 days, ammonium sulphate from 16 to 30 days and potassium nitrate from 31 to 42 days, at the level of 80 kg/ha of N. The fertilizers used during the crop cycle (treatments 4 to 9) were applied through irrigation water. It was found that urea applied through fertirrigation up to 42 days provided higher yield (31.14 ton/ha), not differing, however, from the other treatments, with the exception of the control and ammonium sul- phate, which gave the lowest yields (25.06 and 24.65 ton/ha, respectively). It was found a variation in fruit mean weight from 1.63 to 1.84 kg/fruit. There was no significant difference in total soluble solid content ( o Brix ) among the treatments.

Avaliação do padrão de visitação de Apis mellifera em três cultivares de meloeiro, em Petrolina-PE, Brasil

Para o cultivo do meloeiro, a presenca de abelhas no periodo de florescimento e fundamental para garantir a polinizacao e incrementar a producao de frutos. Nesse sentido, o presente trabalho teve por finalidade verificar se ha diferencas no comportamento de visitas e no recurso floral forrageado por Apis mellifera, em tres cultivares de meloeiro. O trabalho foi desenvolvido no Campo Experimental da Embrapa Semiarido, em Petrolina-PE, com as cultivares do tipo amarelo (BRS Araguaia), pele-de-sapo (P-33) e cantaloupe (CAN-4), com observacoes da biologia floral, morfologia e comportamento de A. mellifera no periodo das 05h as 18h. O pico de visitacao foi diferente, ocorrendo das 11h as 12h; 10h as 11h e das 15h as 16h para o tipo amarelo, cantaloupe e pele-de-sapo, respectivamente. Quanto ao recurso floral forrageado, a coleta de nectar foi constante ao longo do dia, enquanto a de polen ocorreu principalmente no periodo da manha. Quanto ao tipo floral, as flores hermafroditas receberam, de modo geral, mais visitas na cultivar do tipo amarelo e pele-de-sapo, sendo o inverso registrado para a do tipo cantaloupe. O maior numero de visitas registrado nesse tipo floral pode ser atribuido as diferencas morfologicas, uma vez que suas flores sao maiores e, portanto, poderiam ser mais atrativas.