Fertilización nitrogenada y balance de nutrientes en cebada cervecera

the wider use of malting barley with high yield potential will necessarily increase soil nutrient requirements, the resulting nutritional deficiency placing constraints on production. the diagnosis and recommendation integrated system (dris) approach uses leaf nutrient relationships to rank the importance of different nutrients in limiting crop yield. the objectives of the present study were to: a) evaluate the sensitivity of the dris methodology in detecting responses to nitrogen (n) fertilizer; b) establish the ranking of the main macronutrient requirements; and c) determine whether n application improves the nutrient balance in plants. malting barley plants were taken from fertilizer experiments carried out in 1999 and 2000 and sampled at the tillering and heading stages. at tillering, n was found to be the most deficient nutrient in the control and fertilized plots and s in cases where n was more abundant (fertilized with 30 or 60 kg n ha-1). the nutritional balance index (ibn) and n:s ratio show a slight nutritional imbalance at this stage. at the heading stage the plants showed significant n deficiency, followed in many cases by s deficiency, directly affecting yield parameters. no p and k deficiencies were registered in the soils. in 1999, yields were low and showed fertilization response except in alberti, where nitrate availability and yields were high. in 2000, higher water availability gave rise to higher yields with marked deficiencies in n owing to the shortage of n availably at sowing. s alternated with n in the order of requirements and ibn values decreased with increasing n availability. there was an 87% and 68% correlation between this index and the yields of the control and fertilized plots, respectively. the dris approach proved a good indicator of nutritional balance and of plant response to n fertilization.