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found that on a sandy soil with 3 varieties over 3 years yield was increased
from 32.6 to 34.2 t/ha N was applied in split dressings. Table 50 gives results
from Sweden (Svensson et al., 1973) showing no benefit from splitting or
late application. Loud (1977) in a long-term experiment at Ablis compared
applying 160 kg/ha N either as one dose or two applications of 80 kg/ha in
April and May; the latter treatment reduced yield by two t/ha from 32.9 tlha.
Gunasena and Harris (1979) in England obtained results on a sandy soil in
agreement with those of Hunnius and Munzert (1979) on the sandy soil;
splitting a 220 kg/ha N dressing increased the yield of the early cultivar
Craig's Royal by 21% and of the maincrop Pentland Dell by 11%; in these
Table 49. Effect on yield of splitting nitrogen application (mean of 36
annual results)
Application kg N/ha Yield (tlha)
Single 120 48.9
Split 80 + 40 47.5
Single 160 49.4
Split 80 + 80 48.4
Table 50. Effect on yield of splitting and timing of nitrogen applications
(mean of 18 experiments)
Before 4 weeks after Dose of N (kg/ha)
planting planting
10 weeks 15 August Yield (/ha)
after planting
150 - - 33.7
75 - 75 - 32.5
75 - - 75 32.5
225 - - 33.7
150 - 75 - 34.0
150 - 75 33.4
- 150 - - 33.1
experiments there was an advantage (22% for the early and 12% for the
maincrop) in applying all the fertilizer N late. Grewal et al. (1979) in India
found an advantage in splitting a dressing of 120 kg/ha N but no such effect
at lower rates of 40 and 80 kg/ha.
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