ISSN:
1573-5036
Keywords:
Ammonium
;
Ecological climax
;
Energetics of nitrogen nutrition
;
Glucose
;
Glutamic acid
;
Ionic transference and balance
;
Lime and nitrogen fertiliser
;
Nitrate
;
Pasture
;
Perennial ryegrass
;
Protonic exchange
;
Root membrane
;
Thermodynamic model
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The energetics of the assimilation of nitrogen by perennial ryegrass has been studied through a therodynamic model. On a basis of equal amounts of carbohydrate consumed during assimilation, the nitrate form was found to need only 8% more energy than the ammoniacal form. Protonic exchange has been invoked to explain ionic transferences through root membranes, including cases where preferential uptake of metabolically active elemelents produced anion to cation imbalance. The model was also used to draw up a balance sheet for a given amount of metabolised carbohydrate; from this sheet it appeared that in comparison with nitrate nutrition ammoniacal nutrition needed more oxygen and produced more water. The implication of these findings is discussed in relation to shortterm fertiliser and liming trials and in relation to long-term conditions in ecosystems at an ecological climax.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02140720
Permalink
