Effect of the Soil Amendments on the Physical and Chemical Properties of the Soil under Centre Pivot Irrigation System

Abstract

A field trial was conducted to evaluate the application of four soil amendments: sand, gypsum, cow manure and granular sulfur to improve the soil conditions under center pivot irrigation system to manage the mechanization of potato crop harvest in the autumn of 2012; the application of sand amendment was to facilitate mechanical harvest. Evaluation on the improvement of the soil properties were carried out during the growing season through monitoring the changes on soil texture and structure, saturation percentage, bulk density, soil pH and soil salinity. Clods formation occurred at all of the treatments at the harvest time an indication of negative structure improvement due to field trafficking for soil ridging, and spraying during the growing season. The clods samples contained higher %calcium carbonate and higher level of % (Silt+Clay) and less %sand than normal soil samples. Bulk density in the sand treatment was 1.41 gram/cm3 which was significantly higher than the other treatments which ranged 1.13 - 1.19 gram/cm3. Saturation percentage increased at all of the treatments over the period of the experiment from 21 to 31 an indication of significant improvement on the soil water holding capacity. Salinity as measured by the soil Ec was significantly increased over the period of the experiment due to fertilizer application, and salinity at the cow manure treatment was higher than other treatments due to high salt level in the cow manure which reached an Ec average of 5.57 mS/cm over the period of the experiment. Chloride and bicarbonate levels were high and increased on all of the treatments at most sampling occasions of the trial, and sodium level was within the acceptable level.