Melão tipo exportação sob diferentes lâminas de água e frequência de irrigação.

Abstract

The cultivation of the melon (Cucumis melo L.) it is of great importance for the Northeast, socially due the high number of direct and indirect jobs generated during the drought season in the area and, economically why that area holds, now, the largest production, assisting mainly, to the international and center-south markets of the country. In the Northeast region, in 2005/06, that crop, presented a planted area of 11.349 ha (28043 acres) and a production of 273.979 t (2739979 Mg), having the state of Ceara the largest area and production. For the production to assist the standards demanded by the market it is necessary the use of technologies that allow the mitigation of the effects of the limiting factors to the development of the crop. The irrigation besides being one of those technologies is pointed as one of the alternatives for the socioeconomic development of semi-arid areas. However, it should be managed appropriately, in order to avoid problems of degradation of the hydric and edaphic resources. Few agronomic techniques have been developed in the regional scope, considering certain irrigation aspects, above all the soil, water and plant relationships, to determine the best irrigation management for the crop. Among those agronomic techniques, stands out the irrigation frequency and the amount of water to be applied as function, mainly, of the climatic variations and of the physical-hydrics characteristics of the soils. In view of that, it was aimed to analyze the behavior of the melon crop under different hydric regimes allied to the supply timing of this water and its interactions and implication in the production. The experiment was developed in a private area in the Irrigation District of Low Acarau, being used melon seeds, var. inodorus, cv. Fl 10/00 of the "yellow" type, irrigated with different irrigation depths and frequency of water application. The seeds were planted in 2 m (6.6 ft) rows being put two seeds by drip emitter distanced amongst themselves of approximately 12 cm (4.7 in), totaling 24 plants by row. The plants were irrigated with a drip irrigation system, with emitters' flow of 2.3 L h"1, spaced of 0.5 m (1.6 ft), resulting in an emitter for each two plants. The amount of water applied was determined according to the need of replacement of the losses originated by the crop evapotranspiration (ETc). It was evaluated the growth and development of the plants through: the number of leaves, leaf area and dry matter of the aerial part, and the production by: the number, average weight, length and diameter of the fruits. It was also evaluated the total and commercial productivity and the analysis of shelf life (brix and texture). Based on the results, it was verified that the irrigation depths and the frequency of water application didn't interfere in the growth and development variables. The number and average weight of fruits and the productivity was influenced by the irrigation depths; rising lineally with the increase in the water supply. There was significant difference of the frequencies of water application just in the production variables.