A Descriptive Model of Soil Test Nutrient Levels Following Fertilization

1981 ◽  
Vol 45 (3) ◽  
pp. 529-532 ◽  
Author(s):  
F. R. Cox ◽  
E. J. Kamprath ◽  
R. E. McCollum
Keyword(s):  
Soil Test ◽  
Descriptive Model ◽  
Nutrient Levels

INFLUENCE OF FERTILIZER USE ON THE PHOSPHORUS AND POTASSIUM STATUS OF SANDY SOILS

1973 ◽  
Vol 53 (1) ◽  
pp. 103-110 ◽  
Author(s):  
W. I. FINDLAY
Keyword(s):  
Sandy Soils ◽  
Soil Types ◽  
Nutrient Level ◽  
Soil Test ◽  
High Fertility ◽  
Polynomial Equations ◽  
Fertilizer Use ◽  
Nutrient Levels ◽  
Phosphorus And Potassium

Factorially combined rates of 0, 19.6, 39.1, and 58.7 kg/ha P and 0, 37.2, 74.4, and 111.6 kg/ha K were applied annually to plots on soils of different fertility levels. The soil types were Brady and Fox sandy loams. Cropping reduced the levels of phosphorus and potassium in the soil when these elements were omitted from the fertilizer. The decline in phosphorus and potassium levels was more rapid at high fertility levels than low, and much more rapid for potassium than for phosphorus. Where these elements were added as fertilizer, phosphorus and potassium levels in the soil were increased. The increase was greater for phosphorus than for potassium. These changes in soil test levels are described by simple polynomial equations that are used to project the amounts of fertilizer required to maintain certain nutrient levels in the soil. The equations can also be used to predict the amount of fertilizer required to raise an existing nutrient level to some other arbitrarily selected level.

Watch Nutrient Levels in Preemies Sent Home

2005 ◽  
Vol 39 (4) ◽  
pp. 43
Author(s):  
ROBERT FINN
Keyword(s):  
Nutrient Levels

Populations Dynamics of Soybean Insect Pests vs. Soil Nutrient Levels

Crop Science ◽  
1991 ◽  
Vol 31 (6) ◽  
pp. 1629-1633 ◽  
Author(s):  
J. E. Funderburk ◽  
I. D. Teare ◽  
F. M. Rhoads
Keyword(s):  
Insect Pests ◽  
Soil Nutrient ◽  
Nutrient Levels ◽  
Populations Dynamics

Diatom- and Chironomid-Inferred Eutrophication of Bouchie Lake, British Columbia

2005 ◽  
Vol 40 (4) ◽  
pp. 418-430 ◽  
Author(s):  
Markus L. Heinrichs ◽  
Brian F. Cumming ◽  
Kathleen R. Laird ◽  
J. Sanford Hart
Keyword(s):  
British Columbia ◽  
Land Use Changes ◽  
Head Capsule ◽  
Relative Increase ◽  
Nutrient Concentrations ◽  
The Past ◽  
Nutrient Levels ◽  
Lower Head ◽  
Lower Oxygen ◽  
Historical Land Use

Abstract Diatom and chironomid analysis of sediments encompassing the past 400 years from Bouchie Lake, British Columbia, suggests two distinct periods of limnological conditions. Prior to 1950 AD, Fragilaria construens and F. pinnata are the most common diatom species, and Chironomus, Procladius and Tanytarsini dominate the chironomid record. Moderately low nutrient concentrations consistent with oligo-mesotrophic lakes are inferred. From 1950, the diatom assemblage is dominated by Stephanodiscus parvus, a eutrophic indicator, whereas the chironomid communities show a relative increase in littoral taxa coincident with lower head capsule abundance. Higher nutrient levels, specifically total phosphorus, which increased from 8 µg L-1 prior to 1950 to 20 µg L-1 currently, are coincident with midge communities indicative of lower oxygen concentrations. Observed biotic changes and nutrient levels inferred from the sediment core correspond to historical land-use changes.

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