Desempenho do consórcio de alface e cenoura, sob manejo orgânico com irrigação automatizada

Abstract

Two field assays were conducted in Seropédica, RJ, Brazil, to evaluate the yield of carrot and lettuce grown: 1) as monoculture or intercropped, with or without mulch (in 2010); and 2) intercropped, with mulch and under different irrigation levels (in 2011). Both assays were carried out in a randomized block design with 4 repetitions. In 2010, a 3x2 factorial arrangement was applied, combining crop type (carrot monoculture, lettuce monoculture, carrot/lettuce intercrop) and the use (or not) of gliricidia (Gliricidia sepium) mulch. Watering was performed using an automatic controller, operating in response to soil matric potential. In 2011, the irrigation levels were obtained with a combination of drippers of different discharge, resulting in: control (328.8 mm), 125% (412 mm), 185% (602.9 mm) and 215% (711.2 mm) of control levels. Carrots were evaluated for crop yield, fresh matter, length and diameter; and lettuce for yield, fresh matter and diameter. Land equivalent ratio (LER) was evaluated in 2010 and water use efficiency (WUE) in both years. Irrespective of mulching, the agronomical performance of lettuce-carrot intercropping was higher in 2011 than in 2010, likely because of different climatic conditions each year. In 2010, Lettuce crop compromised carrot yield when grown in the intercropping system, but this association increased LER to above 1.0. The use of mulch did not increase carrot and lettuce yield, but increased significantly the diameters of carrot root in 2010 and 2011 and lettuce head in 2011. The carrot root rottenness increased proportionally to the irrigation levels in 2011. In the mulched intercrop system, irrigation depth control produced the highest lettuce (26.07 t ha-1) and carrot root (62.60 t ha-1) yields and the highest water use efficiency (26.97 kg m-3).