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Analysis of Interferences Between C(3) and C(4) Grasses in Relation to Temperature and Soil Nitrogen Supply
Author(s) -
Christie Edward K.,
Delting James K.
Publication year - 1982
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1938855
Subject(s) - competition (biology) , bouteloua gracilis , nitrogen , agronomy , grassland , botany , biology , ecology , chemistry , organic chemistry
The replacement series experimental design and mathematical procedures of de Wit were used to study the influence of soil nitrogen supply and temperature on the growth, in monoculture and in mixture, of two North American grassland species, Agropyran smithii (a C 3 pathway species) and Bouteloua curtipendula (C 4 ). At 20/12°C day/night temperatures, direct competition for soil nitrogen resulted in lowered growth of Bouteloua when growth in mixtures with Agropyran. However, at 30/15° day/night temperature the situation reversed, in that the growth of Agropyron was restricted when grown in the presence of Bouteolua, through competition for nitrogen. Based on the relative crowding coefficient, competitive ability is more closely related to temperature and the photosynthetic pathway type than soil nitrogen supply. The relative crowding coefficient for Agropyron was much greater at 20/12° than 30/15°, whereas values for Bouteloua were greatly depressed at 20/12° compared with 30/15°. Analysis of the competitive and noncompetitive aspects of plant interference occurring in this study is also made. Although differences in nitrogen uptake and use occurred between these two species, the growth differential at two temperatures would result in uneven utilization of the soil nitrogen resource on a seasonal basis. There was little evidence to support the postulate that differences in nitrogen—use efficiency between C 3 and C 4 pathway plants may be advantageous for C 4 plants only.