Competition for nitrogen-15 depleted ammonium nitrate and nitrogen fixation in arrowleaf clover-gulf ryegrass mixtures
Yuchi arrowleaf clover (Trifolium vesiculosum Savi) and gulf ryegrass (Lolium multiflorum Lam) are commonly grown together but their competitive relationship for fertilizer N has not been determined. Two greenhouse experiments were conducted to examine this relationship and to determine the effects on biological N/sub 2/ fixation. Seeds were sown in a Norwood soil that was mixed with vermiculite or sand. Nitrogen was applied at different rates during the seedling stage to plants sown in pure and mixed stands. In Exp. I, plants were grown for 8 weeks. In Exp II, plants were grown for 20 weeks and three clippings were taken. The N source was 99% /sup 15/ depleted NH/sub 4/No/sub 3/. Ryegrass in mixed stand accumulated several times more fertilizer N than its clover component. But clover in pure stand accumulated similar quantities of fertilizer N as the ryegrass in pure stand. The percentage of total N/sub 2/ fixed in the clover was usually decreased with increasing fertilizer N rates due to increased fertilizer N uptake. Total N in the clover from N/sub 2/ fixation was often not significantly altered with increasing fertilizer N rates which indicates that fixed N was complimenting the N taken up from the fertilizer.
- Research Organization:
- Texas A and M Univ., College Station
- OSTI ID:
- 6645736
- Journal Information:
- Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 51:1; ISSN SSSJD
- Country of Publication:
- United States
- Language:
- English
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54 ENVIRONMENTAL SCIENCES
560300 -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL FEEDS
BACTERIA
BIOLOGICAL ACCUMULATION
CEREALS
CLOVER
DISPERSIONS
FERTILIZERS
FOOD
FORAGE
GRASS
ISOTOPE APPLICATIONS
ISOTOPES
LEGUMINOSAE
LIGHT NUCLEI
MICROORGANISMS
MIXTURES
NITRATES
NITROGEN 15
NITROGEN COMPOUNDS
NITROGEN FIXATION
NITROGEN ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
PLANTS
RHIZOBIUM
RYE
SOILS
STABLE ISOTOPES
TRACER TECHNIQUES