Estimation of soil phosphorus levels in shrimp ponds

We estimate the average amount of phosphorus in the soil of four Texas shri mp ponds. Broad spatial trends in phosphorus levels are observed and the tr end is qualitatively common to all four ponds. We calculate and estimate th e bias and variance of the estimated mean, accounting for correlations amon g the measurements. This was done for three different sampling designs and several sampling rates for each design. Using spatial statistical technique s, the diminishing utility of increased sampling is demonstrated tin terms of variance) and the design with the lowest bias is identified. The similar ities between the four ponds suggest that the results are applicable to sim ilar ponds in Texas and elsewhere throughout the world.