ISSN:
1573-5036
Keywords:
Gossypium hirsutum
;
rising CO2
;
root dry weight density
;
root length density
;
root lineal density
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The objective of this investigation was to determine how free-air carbon dioxide enrichment (FACE) of cotton (Gossypium hirsulam L.) affects root distribution in a natural soil environment. For two years cotton was grown on a Trix clay loam under two atmospheric CO2 concentrations (370 and 550 μmol mol−1) and two water treatments [wet, 100% of evapotranspiration (ET) replaced and dry, 75% (1990) and 67% (1991) of ET replaced] at Maricopa, AZ. At early vegetative and mid-reproductive growth, 90 cm soil cores were taken at 0,0.25, and 0.5 m perpendicular to row center; root variables were ascertained at three 30 cm depth increments. The effect of water stress alone or its interaction with CO2 on measured variables during both samplings were rare and showed no consistent pattern. There was a significant CO2 × position interaction for root length density at the vegetative stage (both years) and reproductive stage (1990 only); the positive effects of extra CO2 were more evident at interrow positions (0.25 and 0.5 m). A CO2 × depth × position interaction at the vegetative phase (1990) indicated that FACE increased root dry weight densities for the top soil depth increment at all positions and at the middle increment at the 0.5 m position. Similar trends were seen at the reproductive sampling for this measure as well as for root length density at both sample dates in 1990. In 1991, a CO2 × depth interaction was noted at both periods; CO2 enhancement of root densities (i.e., both length and dry weight) were observed within the upper and middle depths. Although variable in response, increases for root lineal density under high CO2 were also seen. In general, results also revealed that the ambient CO2 treatment had a higher proportion of its root system growing closer to the row center, both on a root length and dry wight basis. On the other hand, the FACE treatment had proportionately more of its roots allocated away from row center (root length basis only). Results from this field experiment clearly suggest that increased atmospheric CO2 concentration will alter root distribution patterns in cotton.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00009960
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