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Nitrogen and Italian ryegrass 5. Growth up to 14 weeks: residual effects
Author(s) -
WILMAN D.
Publication year - 1978
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1111/j.1365-2494.1978.tb00827.x
Subject(s) - residual , dry matter , nitrogen , zoology , yield (engineering) , crop , field experiment , agronomy , mathematics , biology , chemistry , physics , organic chemistry , algorithm , thermodynamics
In a field experiment with Italian ryegrass residual effects of N applied in late April at four rates, 28, 84, 140 and 196 kg ha −1 , and of different dates of first harvest ranging from 1 to 14 weeks after N application, were studied. The harvests after the first added about 10 kg dry matter yield and about 0.16 kg N yield for each extra kg N applied in April. Residual response was similar for each increment of applied N. A positive residual response to N was obtained in May of the year following N application despite high winter rainfall. N content of herbage during part of the summer was reduced by extra N applied in April although N yield was increased. The reduction in N content was accompanied by a reduction in P and K content, these latter elements having been applied only once and at a uniform rate on all plots. Loss of N, P and K from the crop, when a period of more than about 9 weeks regrowth was allowed prior to the first harvest, was not recouped at subsequent harvests. Residual marginal recovery of N in Aberystwyth was no higher than in comparable experiments in Cambridge although marginal recovery of N at the first harvest had been appreciably lower in Aberystwyth than in Cambridge.