Adubação orgânica, nítrica e aplicação exógena de prolina em melancia irrigada com água salina.

Abstract

Irrigation has been considered as an alternative to the socioeconomic development of semi arid regions. However, when used improperly can favor the salinisation and degradation of water and soil resources. Therefore, we aimed to evaluate management techniques, such as the effect of organic fertilizer , nitric and exogenous application of proline in reducing the negative effects of the crop irrigated with saline water watermelon. The experiment was conducted under field condition in the municipality of São João do Rio do Peixe – Paraiba, using the hybrid watermelon 'Quetsali', in the period from 14/07/12 to 16/09/2012. The experimental design was a randomized block design in a factorial 2 x 2 x 2 design with four replications. The treatments consisted of two doses of cattle manure (0 and 20 t ha - 1), two levels of salinity of irrigation water (0.3 and 4.0 dS m-1) and doses of proline (5 mmol L- 1) and N in the form of potassium nitrate. The characteristics evaluated were: dry photosynthetic rate (A), stomatal conductance (gs), transpiration (E), intercellular CO2 concentration (Ci), leaf number, leaf area, dry mass of leaves, stem and fruit and total dry mass, production of fruits, average fruit weight and number of fruits per plant . The use of water with low electrical conductivity (0.3 dS m-1) was more effective in improving the physiology, growth and yield on watermelon in relation to water with high salt concentration (4.0 dS m-1). Proline was more efficient than KNO3 in the osmoregulation of watermelon process by providing higher performance in photosynthesis, intercellular CO2 concentration, leaf number and production. The manure provided physiological, morphological changes and production in watermelon plants subjected to irrigation with saline water.