The influence of nitrogenous fertilizers on the pH and exchangeable base status of certain coffee and citrus soils
Ammonium sulfate or ammonium phosphate applied at rates to supply 12.8 grams of nitrogen to a tree every two months drastically reduced the pH and exchangeable calcium and magnesium of a sandy loam soil immediately around the coffee trees. As much as 50 of the exchangeable calcium and 75 of the exchangeable magnesium were lost from the upper 10 centimeters of soil. Lower pH values and exchangeable calcium and magnesium were also obtained under the trees of seven citrus farms than between the rows. On both the citrus and coffee soils acidification increased the exchangeable manganese but had an inconsistent effect on the exchangeable potassium and sodium and on the available phosphorus. Soil pH determination run on samples taken at different depths and distances from the tree trunks indicated significant acidification around the trees. Average pH values as low as 4.31 were found in the surface soils. Indications were that some soils were acidified below the 45-centimeter layer. The cation exchange capacities of both the coffee and citrus soils were relatively high, the range in milliequivalents per 100 grams soil being from 21.0 to 27.0 for the coffee soil and from 25.8 to 33.0 for the citrus soils. Even though these values indicate a high buffering capacity or a resistance to change in pH, fertilizer application resulted in significant increases in soil acidity
| Main Authors: | , , , |
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| Format: | biblioteca |
| Published: |
Jul
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| Subjects: | SUELO, FERTILIZANTES NITROGENADOS, PH, CATIONES, PROPIEDADES FISICO-QUIMICAS (SUELO), FILIPINAS, CAPACIDAD DE INTERCAMBIO CATIONICO, |
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