Low Soil Cation Exchange Capacity Research Articles

MINERALOGICAL CHARACTERIZATION AND CHEMICAL PROPERTIES OF SOILS AS A CONSIDERATION FOR ESTABLISHING SUSTAINABLE SOIL MANAGEMENT STRATEGIES

Problems of soil limiting factors affecting crop growth were not fully understood owing to little attention has been given to soil mineralogy and its association to soil chemical properties. The objective of the study was to assess soil mineralogical and chemical properties of seven soils derived from different parent<br />materials as an integrated strategic consideration to establish soil management. Field study was carried out in 2009. Soils were sampled from each horizon of profiles. Results showed that primary and secondary minerals had a strong effect on soil chemical properties. The sand fraction of soils derived from basalt, gabbro, mica schist and serpentinite was dominated by resistant minerals (quartz or opaques), leading to very limited, if any, nutrients released from parent materials. The clay fraction was dominated by kaolinite for soils derived from<br />basalt, mica schist and gabbaro, and by amorphous materials for the soil derived from serpentinite resulting in low soil cation exchange capacity (CEC). For other three soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the easily weatherable minerals (feldspar and ferromagnesian) were dominant, suggesting the high reserved nutrients. The presence of halloysite and smectite minerals in the soil derived from volcanic tuff resulted in high soil CEC, while the dominance of amorphous materials in soils derived from volcanic basaltic andesite and volcanic ash was responsible for the low CEC. For<br />soils derived from basalt, serpentinite, mica schist and gabbro, therefore, the strategic management should be directed to restore soil CEC, pH, exchangeable cations and P content. For soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the presence of easily weatherable minerals indicated many reserved nutrients; hence the soil management is directed for replenishment of nutrients removed by crops. <br />

MINERALOGICAL CHARACTERIZATION AND CHEMICAL PROPERTIES OF SOILS AS A CONSIDERATION FOR ESTABLISHING SUSTAINABLE SOIL MANAGEMENT STRATEGIES

Problems of soil limiting factors affecting crop growth were not fully understood owing to little attention has been given to soil mineralogy and its association to soil chemical properties. The objective of the study was to assess soil mineralogical and chemical properties of seven soils derived from different parent<br />materials as an integrated strategic consideration to establish soil management. Field study was carried out in 2009. Soils were sampled from each horizon of profiles. Results showed that primary and secondary minerals had a strong effect on soil chemical properties. The sand fraction of soils derived from basalt, gabbro, mica schist and serpentinite was dominated by resistant minerals (quartz or opaques), leading to very limited, if any, nutrients released from parent materials. The clay fraction was dominated by kaolinite for soils derived from<br />basalt, mica schist and gabbaro, and by amorphous materials for the soil derived from serpentinite resulting in low soil cation exchange capacity (CEC). For other three soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the easily weatherable minerals (feldspar and ferromagnesian) were dominant, suggesting the high reserved nutrients. The presence of halloysite and smectite minerals in the soil derived from volcanic tuff resulted in high soil CEC, while the dominance of amorphous materials in soils derived from volcanic basaltic andesite and volcanic ash was responsible for the low CEC. For<br />soils derived from basalt, serpentinite, mica schist and gabbro, therefore, the strategic management should be directed to restore soil CEC, pH, exchangeable cations and P content. For soils derived from volcanic tuff, volcanic basaltic andesite and volcanic ash, the presence of easily weatherable minerals indicated many reserved nutrients; hence the soil management is directed for replenishment of nutrients removed by crops. <br />

Viral transport through soil columns under conditions of saturated flow

Movement of poliovirus 1, reovirus 3, and bacteriophage OX174 was studied in 8 different soils. Soils were sampled to a depth of 100 cm in three 33 cm profiles, and packed into acrylic cylinders, 10 cm in dia. and 33.66 and 100 cm in length according to the vertical distribution and bulk density of the soil as found in the field. Sequential flooding of the columns with wastewater and distilled water resulted in a cyclical pattern of viral release in column percolates. The total number of viruses detected in percolates differed among the soils tested. This was due to the differences among soil properties. Poliovirus recovery correlated most favorably with low soil cation exchange capacity and high organic carbon and clay content. The recovery of OX174 was related to low soil organic carbon and residence time of liquid within a column in combination with either high soil pH or per cent clay. As with poliovirus, detection of reovirus in soil column percolates was negatively correlated with soil cation exchange capacity.