| Popis: |
Malambito Experiment Station, in the Atlántico III project area, Department of Atlántico, Colombia, had almost no quantitative edaphological data on which to base agricultural research. Unexplainably low general yields as well as problem areas of deficient plant growth only confounded the results of field plot experiments. Intensive soil sampling and subsequent measurements of pH, ECe of the saturation extract, and the four major cations disproved the previous suggestions that the crop growth problems were related to saline, sodic, or degraded soil conditions. The Ca/Mg+K+Na ratio, although significant when correlated with plant height, was sufficient explanation for only a small portion of Malambito problem. The heavy soil texture (50 percent clay) was also shown to be of minor importance in the overall problem. Although no difinitive answer was given to explain the variations in plant growth, a basis for further research was provided, including estimates of soluble plus exchangeable cations and their field variability, pH, organic carbon, ECe and CEC. Future studies in the areas of micronutrient deficiencies and toxicities and possible resistant crops were advocated. Recent research based on the results of this thesis has now implicated heavy metal toxicity as a probably cause for the growth deficiencies and low yields at Malambito. |
