Nitrogen for spring-sown malting barley

• Main Author: McTaggart, Iain Peter
• Published: University of Edinburgh 1992
• Subjects: 631.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657649

Field experiments were carried out to determine the effect of nitrogen on the yield, nitrogen uptake and grain nitrogen concentration of spring barley grown for malting. The effects of the rate, timing of application and the form in which the fertiliser nitrogen was applied were studied. The form of fertiliser nitrogen applied had little effect on grain nitrogen concentrations, except under dry soil conditions, when concentrations were higher using calcium nitrate fertiliser. Calcium nitrate also improved grain yields at low fertiliser rates, but at rates nearer recommended levels there was little difference in yield between fertiliser forms. Split or late applications of fertiliser nitrogen only improved yields when applied as calcium nitrate, and then only when early applications had been followed by heavy rain. At low fertiliser rates, the efficiency of recovery of fertiliser nitrogen (<SUP>15</SUP>N) in plant shoots was greater, when applied as calcium nitrate than when applied as ammonium sulphate or ammonium nitrate. Efficiency of recovery fell at higher rates in calcium nitrate treatments, but rose in ammonium sulphate treatments. Under the dry soil conditions in 1989, the efficiency of recovery was significantly increased in all fertiliser treatments. Uptake of fertiliser nitrogen was rapid in the calcium nitrate and ammonium nitrate treatments, usually reaching a maximum by anthesis. There was evidence of losses between anthesis and harvest of fertiliser nitrogen previously taken up by the crop. The uptake of soil nitrogen in the calcium nitrate treatments remained constant over the range of rates and timings of fertiliser application. There was evidence of increasing uptake of soil nitrogen with increased rates of ammonium sulphate fertiliser at several sites, possibly due to 'pool substitution' of <SUP>15</SUP>N-labelled fertiliser. Uptake of soil nitrogen was less rapid than fertiliser nitrogen before anthesis, but continued right up to harvest in most treatments.