scholarly journals InvasiveAndropogon gayanus(gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna

2009 ◽  
Vol 19 (6) ◽  
pp. 1546-1560 ◽  
Author(s):  
N. A. Rossiter-Rachor ◽  
S. A. Setterfield ◽  
M. M. Douglas ◽  
L. B. Hutley ◽  
G. D. Cook ◽  
...  
Keyword(s):  
Nitrogen Relations

Photosynthesis-nitrogen relations in Amazonian tree species

Oecologia ◽  
1994 ◽  
Vol 97 (1) ◽  
pp. 62-72 ◽  
Author(s):  
P. B. Reich ◽  
M. B. Walters ◽  
D. S. Ellsworth ◽  
C. Uhl
Keyword(s):  
Tree Species ◽  
Nitrogen Relations

Some mathematical aspects of the clover, grass, and fertilizer nitrogen relations

1974 ◽  
Vol 82 (2) ◽  
pp. 331-338 ◽  
Author(s):  
D. A. Stewart ◽  
D. M. B. Chestnutt
Keyword(s):  
Mathematical Model ◽  
Nitrogen Sources ◽  
Apparent Competition ◽  
Large Field ◽  
Nitrogen Transfer ◽  
Interactive System ◽  
Mathematical Equation ◽  
Fertilizer Nitrogen ◽  
Simple Equations ◽  
Nitrogen Relations

SummaryThis article attempts to discuss the relations between the nitrogen sources in data from a large field experiment in which various levels of fertilizer nitrogen were applied to various grass mixtures in the presence and absence of white clover. It was seen that a number of effects occurred, among them the strong depression of clover nitrogen by fertilizer nitrogen (to the extent that equations predicting their contribution to grass nitrogen could not be produced directly by multiple regression but had to be constructed separately), a further apparent depression of clover nitrogen transfer effectiveness, a more significant relationship between grass nitrogen increase and the previous year's clover nitrogen than the current year's clover nitrogen, and apparent competition between grass and clover despite the latter's contribution to increased grass yield.As some of the effects are counteractive, in each comparison made a balance appears to exist. This varies between sites and years in such a way that although the variation in grass nitrogen is always largely dependent on the clover and fertilizer nitrogen the relations are not consistent as shown by the mathematical equation representing them, and cannot be extrapolated or predicted for other sites. It is suggested that a mathematical model be constructed to simulate such an interactive system and that predictions when necessary be made using this, rather than using simple equations.

Soil plant nitrogen relations of tobacco at Mareeba, north Queensland

1965 ◽  
Vol 5 (17) ◽  
pp. 180
Author(s):  
PJ Goodman
Keyword(s):  
Nitrogen Uptake ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Soil Nitrate ◽  
Nitrate Accumulation ◽  
Plant Nitrogen ◽  
Leaf Nitrogen Concentration ◽  
Red Earth ◽  
Nitrogen Relations

Nitrogen changes were studied in a red earth on which tobacco grew with very small additions of nitrogen fertilizer. Soil nitrate accumulation in the dry season before transplanting, and mineralization during the tobacco season, provided most of the plant's nitrogen requirements. Plant nitrogen uptake continued longer than in other countries, and the total amount was greater, particularly in stems and suckers. Though the plants gained nitrogen during the harvest period, leaf nitrogen concentration decreased. This resulted from translocation from lower leaves and growth of upper leaves. Decrease in leaf nitrogen concentration was essential to quality. The necessary sequence, of sufficient nitrogen for yield, followed by decreasing nitrogen availability for quality, occurs on this soil with small fertilizer additions. There is need for survey work on nitrogen availability and the time sequence of nitrogen uptake by plants on related Mareeba soils.

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