Illustrated Concepts in Tropical Agriculture, 1970 - 1981

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    Green Manuring—Renewed Interest in an Old Concept
    (University of Hawaii, 1981) Yost, R.S. ; Evans, D.O. ; Saidy, N.A. ; Fox, R.L.
    Three tropical green manure legumes were grown across a pH gradient from 4.7 to 7.1 established by liming an Oxisol. The effects of available soil aluminum and manganese levels on plant growth and nitrogen fixation are discussed.
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    Liming in the Tropics: Variable-Charge Soils May Be Highly Buffered
    (University of Hawaii, 1981) Fox, R.L. ; Saidy, N.A. ; Yost, R.S.
    Yield response of cowpea over a pH gradient established by applying incremental amounts of lime to an Oxisol is illustrated and discussed.
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    Mapping Soil Fertility and Fertilizer Requirements
    (University of Hawaii, 1980) Fox, Robert L. ; Yost, Russell S.
    A map of fertilizer phosphorus requirements for the island of Hawaii is discussed. It shows the amount of P fertilizer required per gram of dry soil to establish 0.02 microgram P per milliliter of soil solution, a level that is capable of producing near-maximum yields of many agronomic crops.
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    Amorphous Coatings on Soil Mineral Surfaces Sorb Phosphate and Sulfate
    (University of Hawaii, 1978) Jones, Rollin C. ; Fox, Robert L.
    Soils formed in weathered volcanic ash usually contain a high percentage of amorphous gel-like material that has been desilicated during weathering. The influence of this property on phosphate and sulfate sorption is discussed.
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    The External Phosphorus Requirements of Plants
    (University of Hawaii, 1980) Fox, Robert L. ; Nishimoto, Roy K.
    The dynamic between labile P, soil solution P, and P uptake by lettuce and Chinese cabbage is illustrated.
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    Symbiotic Nitrogen Fixation by Legumes Requires Extra Phosphorus
    (University of Hawaii, 1980) Cassman, Kenneth ; Whitney, A Sheldon ; Fox, Robert L.
    Soybean plants that depend upon symbiotic nitrogen fixation for their N have a higher P requirement than their counterparts supplied with fixed N from an external source.
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    Premature Leaf Senescence of Banana—A Symptom of Potassium Exhaustion
    (University of Hawaii, 1980) Fox, Robert L. ; Lower, Robert
    Tropical soils may lack reserves of available K due to nutrient leaching, and harvesting of K-rich crops such as banana may deplete the limited reserves. Symptoms of gradually increasing K deficiency over a 6-year period are illustrated and described.
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    Nitrogen and Potassium Interact to Shape a Yield Response Surface
    (University of Hawaii, 1980) Fox, Robert L. ; Lower, Robert ; Warner, Robert M.
    In a field experiment with banana, fertilizer variables were applied systematically in strips across the blocks so that N increased gradually from none to large quantities in one direction, while K increased gradually perpendicular to the N fertilizer. An aerial view of the blocks and a plot of banana yields as influenced by the variables illustrate the interaction of the nutrients applied.
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    Matching Crop Requirements to Land Characteristics
    (University of Hawaii, 1980) Manrique, Luis A. ; Harris, David J. ; Uehara, Goro
    Examples of matching crop, soil, and season are given; implications for technology transfer in the tropics are mentioned.
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    Mycorrhizae Enhance Nutrient Uptake from Infertile Soils
    (University of Hawaii, 1980) Yost, Russell S. ; Fox, Robert L.
    A field experiment to illustrate how removing soil mycorrhizae through fumigation affects the growth of crops dependent on the symbiosis is discussed.