José Maria Pinto

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.

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.

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.

Aplicação de co2 via água de irrigação em relação à produtividade do meloeiro

ABSTRACT: The melon crop represents an important contribution to the total Brazilian agricultural export.Carbon dioxide concentration was assumed to be 250µmolCO 2 mol -1 before industrial revolution, achieving315 µmolCO 2 mol -1 in 1958. Nowadays it is approximately 365 µmolCO 2 mol -1 , with a tendency of increasing. Inthis research the effect of carbon dioxide application through irrigation water on melon fruit productivity andchemical characteristics was evaluated. A trickle irrigation system was used. The carbon dioxide applicationswere daily and three times a week, in three different types of crop management: lateral protection, mulchingand soil without protection. The carbon dioxide application through irrigation water did not alter the melon cropseason, and it did not affect the fruit chemical characteristics, such as soluble solids content, total acidity andpH. The highest yield was obtained with carbon dioxide application through irrigation water.Keywords: Cucumis melo, photosynthesis, fruit quality

Composto orgânico em mangueiras (Mangifera indica L.) cultivadas no semiárido do nordeste brasileiro

The objective of this study was to evaluate the soil chemical characteristics, the nutrient contents in leaves and the production of mango crops grown in the organic system. An experiment was carried out with three composts named A, B and C, using three levels (0, 5 and 10 t ha-1) of each compost in a commercial production of mango on organic cultivation. The experiment was carried out in a randomized block design, 3 x 3 factorial (3 composts x 3 levels) and three replications. The organic composts were prepared with animal and vegetable waste, enriched with castor bean, MB4® and thermo phosphate. The enrichment was efficient in increasing the content of nutrients in composts. The organic composts increased the levels of soil organic matter (SOM), especially in the compost C, whose soil analysis showed higher levels of total P, K, Ca, Mg, B, Cu, Mn and Zn. The SOM increased linearly with the enhancement of the compost levels. Production and fruit number per plant were higher with the use of the B and C composts, which showed higher contents of total nutrients. The compost levels provided a linear increase in N leaf content. The production of fruit (kg ha-1) and fruit number per plant showed quadratic increase with the compost concentrations, without presenting a maximum point.

USO DE DIÓXIDO DE CARBONO NA AGRICULTURA

The carbon cycle in the biosphere has been significantly altered by mans activities in the last 150 years. The CO2 emitted by human activity is approximately 8.5 billion of tons yearly, as a consequence, the carbon dioxide concentration is increasing. Studies related to the artificial increase effects of CO2 concentration on plants used for obtaining products in greater quantity and with a better quality permit us to know the capacity of the plants to adapt in this environment. Therefore, factors related to the application of carbon dioxide need more accurate studies concerning to carbon dioxide changes.

Cultivo de melão orgânico: fosfatos naturais como fontes alternativas de fósforo

Aiming to evaluate the efficiency of natural phosphates in melon organic cropping under irrigation, two experiments were carried out in Petrolina-PE, one in a Yellow Argisol (PA) and other in a Grey Argisol (PAC). The evaluated treatments were: 1 - without P, 2 - 50 kg ha-1 of P2O5 as triple super phosphate (TS), 3 - 100 kg ha-1 of P2O5 as TS, 4 - 150 kg ha-1 of P2O5 as TS, 5 - 100 kg ha-1 of P2O5 as thermo phosphate, 6 - 100 kg ha-1 of P2O5 as natural phosphate of Gafsa and 7 - 100 kg ha-1 of P2O5 as natural phosphate Fosbahia. The melon crop showed similar responses to the P application in both soils, whose maximum productivities of 26.00 t ha-1 and 25.46 t ha-1 were obtained with 107.6 kg ha-1 and 118.6 kg ha-1 of P2O5 in PA and PAC, respectively. The efficiency of thermo phosphate, phosphate of Gafsa and Fosbahia in relation to TS assumed the sequence of 86.2%, 77.1% and 71.9% in PA and 101.5%, 72.3% and 67.3% in PAC. These results suggest that thermo phosphate is the most appropriated phosphate source to be used in the melon organic cropping. It is necessary 843.12 kg of thermo phosphate to produce 25 t ha-1 of melon fruit that represent 3.4% of the production cost.

Efeito de fosfatos naturais em plantas de melão cultivadas em vasos.

Organic agriculture is an emerging activity in the upper mid Sao Francisco River Valley, requiring technologies that are in line with the principles of this agricultural system. A study was carried out at Embrapa Semi-Arido to evaluate the efficacy of natural phosphates applied to three regional soils (dystrophic Grey Argisol - PAGd, eutrophic Yellow Argisol - PAe and Vertisol - V) planted with melon (Cucumis melo) in pots accommodated on wooden benches. The factorial treatments (3 x 4) + 1 consisted of three phosphorus levels (40, 80 and 160 mg dm-3 P2O5), four phosphorus sources (triple superphosphate-ST, thermophosphate-TM, Gafsa natural rock phosphate-FG and Fosbahia natural phosphate-FB) and a control treatment without phosphorus, in a completely randomized design with three replications. Each soil represented a trial. Shoot dry matter (DM), P plant content and P soil concentration extracted by Mehlich-1 and anionic exchange resin (AER) were evaluated 38 days after planting. In V and PAGd soils the phosphates were less effective than in PAe soil. TM was the P source with the highest efficiency for DM production in the three soils (56 to 100 % in relation to triple super phosphate). In PAe, FG also presented relatively high efficiency, equivalent to 80 % of that obtained with triple super phosphate. The Mehlich-1 and AER extractors were equally effective at evaluating P availability.

Rendimento e conservação pós-colheita de bulbos de cebola com doses de nitrogênio e potássio

This study was carried out from March to November 2001, in Petrolina, Pernambuco State, Brazil, to evaluate the influence of nitrogen and potassium levels applied through fertirrigation, on yield and post-harvest quality of onion bulbs. Cultivar Franciscana IPA- 10 was used in a randomized complete block design, in a 4 x 3 factorial arrangement, with four nitrogen levels (0; 60; 120 and 180 kg ha-1) and three potassium levels (0; 90 and 180 kg ha-1 of K2O) with three replications. The applied levels of nitrogen showed linear effects on the commercial yield independent of the potassium fertilization. The non-commercial yield (calls) showed linear reductions in the three potassium levels, with the increase in nitrogen levels. With the increase of applied nitrogen levels a linear effect on the fresh mass of the bulbs was observed. There were no significant effects of nitrogen and potassium application on the mass loss of the bulbs at 40 and 80 days after cure.O experimento foi conduzido de marco a novembro de 2001, em Petrolina-PE, com o objetivo de avaliar a influencia de doses de nitrogenio e potassio aplicadas via fertirrigacao sobre o rendimento e conservacao pos-colheita da cebola. Utilizou-se a cultivar Franciscana IPA-10, no delineamento experimental de blocos ao acaso, em esquema fatorial 4 x 3, compreendendo quatro doses de nitrogenio (0; 60; 120 e 180 kg ha-1) e tres doses de potassio (0; 90 e 180 kg ha-1 de K2O), com tres repeticoes. A adubacao nitrogenada apresentou efeitos lineares positivos na produtividade comercial independente da adubacao potassica. Para a produtividade nao comercial (refugos) constataram-se reducoes lineares na ausencia da adubacao potassica e nas doses de 90 e 180 kg ha-1 de K2O, com o incremento das doses de nitrogenio. O aumento das doses de nitrogenio proporcionou um incremento linear na massa fresca dos bulbos. Nao se constataram efeitos significativos para perda de massa aos 40 e 80 dias apos cura, com a aplicacao de nitrogenio e potassio.

Nitrogen levels through fertirrigation and plant density on melon crop in a Vertisol

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.