Effect of nitrogen rate and variety on barley grain yield and protein content

Increasing local malt production in Lithuania has boosted the demand for barley grain, meeting specific market requirements. Varieties with a high malting quality potential have been recently introduced in Lithuania and this study is aimed at their response to nitrogen fertiliser rate. Field experiments were conducted during 2000-2002 on a loamy soil at the Lithuanian Institute of Agriculture, Kedainiai district, Lithuania. Experimental plots were sown with the varieties Ottis, Scarlett and Barke and were applied with different rates of ammonium nitrate (0, 30, 60, 90 and 120 kg haE-1 of N). The growing seasons 2000 and 2001 could be characterized as normal and 2002 as dry. The varieties showed a rather similar yield level and protein content in grain, and the interaction between varieties and nitrogen rate was non significant in most cases. The only exception was found in 2001, when the variety Scarlet produced a significantly higher yield than Ottis and Barke (by 0.32 and 0.62 t haE-1, accordingly). The effect of nitrogen rate on grain yield was highly significant in all three experimental years, with much higher increases in the yield in the years with normal precipitation and lower - in a dry the season of 2002. The yield was closely correlated with the number of grains per square m and in a dry season was much lower than in normal moisture conditions, because of the lower number of ears per square m. The effect of nitrogen on the number of grains was positive and close to linear in the range of N rate up to 90 kg haE-1. Protein content in barley grain was below 115 g kgE-1 with the application of nitrogen rates up to 90 kg haE-1 in 2000 and up to 60 kg haE-1 in 2001. In the dry growing season 2002 grain had too high protein content (above 130 g kgE-1) in all treatments. In droughty years growers must take appropriate marketing measures to alleviate negative effects on income, since technological practices have rather limited effect.