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Effects of nitrogen supply on competition between wheat and three annual weed species
Author(s) -
IQBAL J.,
WRIGHT D.
Publication year - 1997
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1046/j.1365-3180.1997.d01-69.x
Subject(s) - weed , competition (biology) , agronomy , nitrogen , biology , chemistry , ecology , organic chemistry
Summary Three pot experiments have investigated the effects of nitrogen (N) supply on interspecific competition between three weed species ( Phalaris minor Retz., Chenopodium album L, and Sinapis arvensis L.) and spring wheat ( Triticum aestivum L.) cv, Alexandria. The treatments tested included monocultures of each species and a mix‐ture containing them in equal proportions that were combined factorially with two levels of N supply (20, 120 kg N ha ‐1 ). Low N supply decreased net photosynthetic rate (P n ), leaf N percentage, plant dry weight and N uptake of both wheat and weed species and gram dry weight of wheat. The effects of low N on P n and dry weight of weeds were greater than the effects on wheat. In most cases the decrease in P n at low N was due to non‐stomatal factors. The relative competitive abilities of wheat and weeds were influenced by N supply. At high N, S.arvensis was more competitive than wheat, whereas P. minor was less competitive than wheat. C. album was more competitive than wheat at both N levels. The rank order of competitive ability of the weed species was C. album > P. minor > S. arvensis . The effects of interspecific competition on P n were smaller than the effects of N supply and were not associated with corresponding effects on leaf N percentage and plant dry weight of both wheat and weed species and grain dry weight of wheat.