GENERAL34209 - Laserfiche WebLink

Home Browse Search

1 1 1 1 t 1_ I 1 Fertility of the samples is low since no natural sources of many elements, especially nitrogen and phosphorus, are found in this soil (Table 2). Also the texture of the samples was a typical sandy loam throughout (Table 3). Some of the structure appeared to be destroyed as a result of the heavy equip- went. Also, as expected, organic matter and saturation percentages are low; the low organic matter contents are a consequence of little or no vegetation occurring at the lower horizon depths, and the low saturation percentages are due to the sandy loam texture of the soils. A sandy loam soil has much less pore space than does a silt loam soil, for example, and thus less water is required to gain saturation. The sodium adsorption ratios (SAR) are high, but may decrease slightly as some leaching occurs. Since yearly average precipitation is about 9 inches in this area, only slight leaching may ocur during a short-term storage duration, and, in effect, would only serve to concentrate the salts at lower depths in the stockpile. Where the conductivities are low, the high SAR's should be of little consequence since the soil is relatively sandy. Generally, an SAR greater than 15 is considered to be a hazard with respect to sodium. The effect of sodium on soil is mainly on its structure. Sodium has the unique ability to break apart the structure of a soil by dispersing the clay particles of the soil. This, in effect, seals the soil and slows down water infiltration dramatically. Since the soil in question is predominately sandy, [he sodium should have a lessened effect on the soil structure. Therefore, an SAR of 25 could conceivably be tolerated as long as the electrical conduc- tivity is 10 mmhos/cm or less. Any instance in which a conductivity greater than 10 mmhos/cm is encountered, most plant species will be adversely affected. 1