Nitrogen cycling: water use efficiency interactions in semi-arid ecosystems in relation to management of tree legumes (Prosopis)

Conference · Tue Apr 01 04:00:00 EST 1980

OSTI ID:5179450

Felker, P; Clark, P R; Osborn, J; Cannell, G H

Plant productivity in semi-arid ecosystems is often limited by soil fertility as much as it is by moisture availability. A quantitative assessment of nitrogen limitations on water use efficiency has been made after careful review of plant water use efficiency data at high and low soil fertilities and after careful review of nitrogen inputs to semi arid ecosystems in the form of: blue-green algae-lichen crusts; non-symbiotic nitrogen fixers; rainfall; and tree legumes. This analysis indicates that plant productivity in semi-arid regions may be 10 fold more limited by nitrogen than moisture availability. Forage yields of non-nitrogen fixing trees and shrubs could be greatly increased by interplanting with drought adapted nitrogen fixers such as Prosopis and Acacia. Calculations based on water use efficiencies of annual legumes and nitrogen fixation values of tree legumes predict that well managed, spaced, and cared for orchards of specially selected Prosopis could produce 4000 Kgha/sup -1/ yr/sup -1/ of 13% protein pods at 500 mm annual rainfall with only light fertilization with phosphate, potassium and sulfur. Field measurements of pod yields for 25 selections of 3 year old Prosopis grown under managed orchard conditions in southern California are presented. Spacing regimes and harvesting techniques for Prosopis are proposed to facilitate pod production.

• Research Organization: California Univ., Riverside (USA)
• DOE Contract Number: FG01-78ET20023
• OSTI ID: 5179450
• Report Number(s): CONF-8004108-1
• Country of Publication: United States
• Language: English

Related Subjects

510100 -- Environment
Terrestrial-- Basic Studies-- (-1989)
54 ENVIRONMENTAL SCIENCES
553000* -- Agriculture & Food Technology
60 APPLIED LIFE SCIENCES
ARID LANDS
CRYOGENIC FLUIDS
DATA
ECOSYSTEMS
ELEMENTS
EXPERIMENTAL DATA
FERTILIZERS
FLUIDS
INFORMATION
LEGUMINOSAE
NITROGEN
NITROGEN FIXATION
NONMETALS
NUMERICAL DATA
PLANTS
PRODUCTIVITY
RECOMMENDATIONS
TERRESTRIAL ECOSYSTEMS
WATER REQUIREMENTS