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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. [ABSTRACT FROM AUTHOR]

There is a lack of data associated with applications of nitrogen fertilizer to increase yield while not increasing seed protein to levels exceeding those acceptable for malting barley in Buenos Aires province. Field experiments were carried out on eight sites between 1999 and 2000 to determine the effect of nitrogen on the growth, soil and fertilizer uptake, yield and grain nitrogen concentration of barley grown for malting. The treatments were: 0,30 and 60 kg N ha-1 applied as a whole at plant emergence, 30 and 60 kg N ha-1 applied as a whole at early tillering, and 60 kg N ha-1 applied in split applications of 30 kg N ha-1 each at emergence and at early tillering growth stages. Within each plot there was a microplot to which 15N-labelled urea was applied. Above ground dry matter production and N uptake were measured at four sampling times from early tillering to physiological maturity from plant samples taken from the microplots.The growth continued to physiological maturity, and maximum growth was usually reached after anthesis, following the period of greater nitrogen uptake. The rate of 30 kg N ha-1 increased yield but not the grain N concentration. The addition of 60 kg N ha-1 affected both yield and grain N concentration. N application time did not affect the dry matter yield nor the N concentiation of grain. The variation in soil N uptake between sites was greater than the variation in fertilizer nitrogen uptake. The Nitrogen Harvest Index was not affected by the rate of N application. [ABSTRACT FROM AUTHOR]