Effect of irrigation and potassium application in melon (Cucumis melo L.) production. I: Yield

摘要

The influence of different watering levels and potassium applications on yield and its components was studied over a two-year period. The experimental design was a split-plot with four replications. Water levels were determined according to wateringneeds (NRc) calculated on the basis of crop evapotranspiration. Four treatments were tested: 1.25 NRc; 1.00 NRc; 0.75 NRc, and 0.50 NRc. Two potassium treatments were applied: K_0 (no potassium) and K_1 (375 kg/ha of K_2O in 1995 and 6 L/ha of a commercial product containing 20 percent of K_2O in 1996). The potassium levels tested did not influence the concentration of foliar nitrogen, phosphorus, potassium, or any of the production parameters studied. Therefore, in terms of productivity, potassium fertilization could be avoided in soils with high potassium levels. The maximum yield obtained was approximately 35 t/ha in the 1.00 NRc treatment (395 mm in 1995 and 430 in 1996). No significant differences were observed between this one and the highest water treatment. The lowest water treatment caused an important decrease in yield. This was due to a significant reduction of fruit number and weight. At harvest time, the highest yields were obtained at 88 and 105 days after emergence. The increase of yield per water applied was larger at the low watering levels. The differentials were 13.7 kg/m~3 (1995) and 14.4 kg/m~3 (1996) in the 0.50 NRc treatment, and 8.4 kg/m~3 (1995) and 8.6 kg/m~3 (1996) in the 0.75 NRc treatment. In the latter treatment, the highest water efficiency was obtained.