Sampling the Unsaturated Zone in Irrigated Field Plots

Abstract

Abstract Data obtained from samples from each of 10 holes/plot for one plot from each of three soils were subjected to statistical analysis and used to formulate plans for sampling the 1.5‐ to 4.5‐m depth of 48 experimental plots that had received animal manures. The statistical analysis of these three plots suggested that 10 holes/plot and 10 samples/hole would provide plot means within about 20% of the true means for nitrate and chloride concentrations and electrical conductivity of saturation extracts, EC e , except for one soil which had residual salts in highly variable concentrations at the 3.0‐ to 4.5‐m depth. The sampling procedure developed gave satisfactory results when statistical analysis of the effects of manure treatments, soils and irrigation levels on nitrate, chloride and EC e were measured.