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An analysis of the uninterrupted growth of white clover swards receiving either biologically fixed nitrogen or nitrate in solution
Author(s) -
ARNOTT R. A.
Publication year - 1984
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.1365-2494.1984.tb01700.x
Subject(s) - stolon , petiole (insect anatomy) , dry matter , sowing , lamina , dry weight , biology , agronomy , leaflet (botany) , leaf size , nitrogen , perlite , horticulture , botany , chemistry , hymenoptera , organic chemistry
White clover swards were grown in a freely ventilated glasshouse during August and September 1979. The uninterrupted growth of these swards, which were grown in Perlite with either nitrate or biologically fixed nitrogen, was studied from 5 weeks after sowing until peak dry weights of the live sward components occurred. The dry weight of leaf laminae, petioles, stolons, roots, nodules and dead material was determined weekly together with live leaf numbers and leaf lamina area. The pattern of dry matter accumulation of the yield components of the swards (live leaf laminae plus petioles) was characterized by an initial period of more or less exponential growth up to 6 weeks from sowing dominated by leaf lamina development. This was followed by a linear phase, when petiole weight increased rapidly and a final slowing down period terminated by peak yields of live DM 12 weeks after sowing. The weight of stolons, roots and nodules increased slowly during the period dominated by leaf lamina growth compared with the rapid increase thereafter, which resulted in a two‐ to three‐fold increase in the weight of stolons, roots and nodules by the time the weights peaked. It is assumed that after the leaf area index of the sward had reached a plateau there was a limit to the assimilate supply to the sward components at a stage when they were all apparently competing for photosynthates. There was a progressive slowing down in the rate of dry matter accumu‐