Broccoli Raab (Brassica rapa L.) water uses

Two-year researches were carried out in southern Italy (40 degrees N. L.) during autumn-winter period on broccoli raab (cv. Centoventina) grown in a weighing lysimeter, on deep clay-silty soil. The crop was sown in rows 0.7 m apart obtaining, after thinning out, a planting density of 8 plants m(-2). The different climatic trend of the two years considerably influenced the crop cycle length, water uses and areic yields. The lower temperatures of the first year caused a longer crop cycle (176 days vs. 137 days of the second year) and greater yields (25.2 t ha(-1) vs. 14.0 t ha(-1) of the second year). The evapotranspiration during the crop cycles was 364 and 180 mm, respectively in the first and second years. The evapotranspiration coefficient was 144.4 and 128.61 kg(-1) with water-use efficiency of 6.92 and 7.77 g l(-1). This great difference was mainly due to the higher evapotranspirative demand of the first year and to the longer crop cycle which lasted up to the end of the winter. The ten days crop coefficients relating to "class A" pan evaporation varied from 0.72 to 1.20 and 0.68 to 1.13, respectively in the first and second years.