• The Effects of Seed Treatment, Sowing date, Cultivar and Harvest date on the Yield and Quality of Sugar Beet

      O'Donovan, Timothy; Irish Sugar Plc; Germain’s U.K. (2002)
      Trials were carried out at Lyons Estate Research Farm during 1998 on sugar beet (Beta Vulgaris). The commercially available seed treatment ‘Advantage’ was tested across 3 sowing dates, 4 commercially available cultivars and 4 harvest dates. Trials were carried out in a factorial arrangement and subject to standard statistical analysis. Data on emergence, ground cover, yield and quality was analysed. Percentage emergence of seed was satisfactory in all experiments. The benefit of ‘Advantage’ treatment during the emergence stage of growth was clearly seen in all trials. On average ‘Advantage’ seed emerged 2-3 days earlier than untreated seed and reached the target population (>75,000 plants/ha 4 days sooner than the control seed. During the growing season, ground cover was measured until complete cover was reached. In the trials it was less clear as to the benefits of using the treatment ‘Advantage’, as it was seldom statically different from control seed. As yields can be related to the radiation intercepted, it is not surprising that there were not large differences in yields. Delaying sowing date resulted in decreased yields of clean beet, sugar and extractable sugar. The two triploid varieties, Libra and Accord gave better yields of clean beet, sugar and extractable sugar than the two diploid cultivars Zulu and Celt. Delaying harvesting gave increased yields of clean beet, sugar and extractable sugar. The ‘Experimental’ seed treatment was not superior to the ‘Advantage’ treatment. In only one of the experiments was ‘Advantage’ better than the control treatment in respect of yield of clean beet, in the time of harvest trial. This was not reflected in yield of sugar or extractable sugar. In all other situations, there were no differences between ‘Advantage’ and the control treatments. There was no benefit from using ‘Advantage’ seed in the current experiments. However earlier sowing dates require investigation with pre-treated seed.
    • Effects of urease and nitrification inhibitors on yields and emissions in grassland and spring barley

      Forrestal, Patrick J.; Wall, David; Carolan, Rachael; Harty, Mary A.; Roche, Leanne; Krol, Dominika; Watson, C. J.; Lanigan, Gary; Richards, Karl G.; Department of Agriculture, Food and the Marine, Ireland; et al. (International Fertiliser Society, 09/12/2016)
      In trials conducted in the temperate maritime climate of Ireland on a range of acidic soils, calcium ammonium nitrate (CAN) and urea gave comparable yield performance. There was little evidence of reduced yields by using urea for grassland or spring barley. Our finding that urea produced annual yields that were not significantly different from CAN differs from previous studies which found that yields from urea were lower than those from ammonium nitrate or nitrate based fertiliser in the UK. However, there are also published results from trials conducted in temperate Irish grassland showing equal yield performance of CAN and urea in the 1970s. Based on yield performance and the cost of fertiliser there is scope to dramatically increase the level of urea usage in straight and blended fertilisers in the temperate maritime climate of Ireland in both grassland and spring barley. Such an increase will bring substantial benefits in terms of reducing direct nitrous oxide (N2O) emissions from fertiliser applied to soil, particularly in poorly draining soils subject to high levels of precipitation. Nitrogen recovery by plants tends to be more sensitive to differences in fertiliser efficiency than is yield. Although yields did not differ between urea and CAN; urea had a lower nitrogen recovery indicating that urea usage will also result in a reduced level of fertiliser use efficiency. Reduced efficiency is less tangible to farmers who tend to be primarily concerned with dependable yield results. Reduced efficiency is a problem nonetheless, particularly as it is closely linked to NH3 emissions in urea usage. European countries including Ireland have committed to reduce national NH3 emissions to comply with the revised National Emission Ceilings Directive (2001/81/EC) in Europe. Increased urea usage, which looks attractive from a yield, cost and direct N2O perspective in Ireland, runs counter to meeting these commitments. Additionally, NH3 is a source of indirect N2O emissions that will negate some of the N2O savings from urea. Due to the issues of yield dependability, fertiliser efficiency, N2O and NH3 emissions the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) is a particularly attractive option for making urea use more efficient by addressing its key weakness in the area of variable NH3 loss and efficiency. The urease inhibitor NBPT along with the nitrification inhibitor dicyandiamide (DCD) were tested with urea in comparison with calcium ammonium nitrate (CAN). The nitrification inhibitor DCD was very effective in reducing fertiliser N associated N2O emissions. Indeed, its usage allowed N2O levels to be reduced to levels comparable to where no application of N fertiliser was made at some site-years. However, at the DCD incorporation rate tested, DCD contributed to variability in NH3 loss from urea and suppressed both yield response and fertiliser efficiency. Use of the urease inhibitor NBPT in addition to DCD went a substantial way to resolving these shortcomings. Continuing work is needed to tailor the rate of existing and new urease and nitrification inhibitors to optimise the balance between suppression of gaseous N emissions, agronomic performance and economic considerations.
    • Response of two-row and six-row barley to fertiliser N under Irish conditions

      Hackett, Richard (Teagasc (Agriculture and Food Development Authority), Ireland, 2016-12-30)
      A range of cultivar types, including two-row and six-row types as well as line and hybrid types, are used for winter barley production in Ireland. There is little information available on the fertiliser nitrogen (N) requirements or the N use efficiency of these different types, particularly under Irish conditions. The objectives of the work presented here were to compare the response to fertiliser N of a two-row line cultivar, a six-row line cultivar and a six-row hybrid cultivar in terms of grain yield and aspects of N use efficiency. Experiments were carried out over three growing seasons, in the period 2012-2014, on a light-textured soil comparing the response of the three cultivars of winter barley to fertiliser N application rates ranging from 0 to 260 kg N/ha. There was no evidence that cultivar type, regardless of whether it was a two-row or six-row line cultivar or a six-row hybrid cultivar, influenced the response to fertiliser N of winter barley. There were some indications that six-row cultivars were less efficient at recovering soil N but used accumulated N more efficiently than the two-row cultivar. This work provided no evidence to support adjustment of fertiliser N inputs to winter barley based on cultivar type