[Irrigation and nitrogenous fertilization during the first establishment year of an asparagus plantation]

The response of a one-year old asparagus (Asparagus officinalis L.) crop to different irrigation and nitrogenous fertilization treatments was studied in a field trial at La Platina Experiment Station (INIA) during the 1987-88 season. In the irrigation treatments, decreasing water charges, from 84.5 to 5.2% of the evaporation of the U.S. "Class A" pan, were periodically applied by sprinklers with four replications. The fertilization treatments consisted of four nitrogen doses: 0, 75, 150 and 225 kg/ha applied in bands in right angle to the sprinkling line with four replications. The statistical design consisted of split blocks with an unrandomized irrigation factor which was analyzed by means of regressions. Conversely, the treatments with nitrogenous fertilization were analyzed with variance analysis. The water charges applied influenced the crop development. High charges resulted in greater plant growth, greater root development, more stems per plant, greater stem diameter and more dry matter of the subsurface and total aerial biomass. The resulting Ky between the relation of the relative yield decreases with evapotranspiration gave a value of 1.39 indicating that the asparagus crop is highly sensitive to hydric deficit. A greater amount of roots was found and more water was extracted at the first 40 cm of the soil profile. The increasing doses of nitrogenous fertilizer resulted in a significant difference in the number and diameter of stems but not in plant growth; neither did they affect the plants nutrient content (N, P, K, Ca; Mg, Zn, Mn, and Cu). Interaction between irrigation and nitrogenous fertilization was found in the dry matter production of the total biomass; nor was it found in the N, P, K, Ca, Mg; Zn, Mn and Cu content in the plants. However, there was a very good correlation between the dry matter of the total biomass and the amount of the above mentioned nutrients extracted by the plants