DETERMINING THE BOTTOM SOIL SAMPLING RATE IN SHRIMP PONDS USING VARIOGRAMS

In aquaculture, methods for collecting soil, that represent the mean c oncentrations of its constituents are not well established. We use the variogram technique to determine the distance between two locations w here soil phosphorous is no longer correlated. Using this technique, w e estimate that samples need to be taken between 15 and 20 m apart to compose a composite sample that represents the average amount of phosp horus in the soil of four Texas shrimp ponds. Broad spatial trends in phosphorus levels are observed and the trend is qualitatively common t o all four ponds. The similarities among three of the four ponds sugge st that the results are applicable to similarly managed shrimp ponds i n Texas; and elsewhere throughout the world. (C) 1998 Elsevier Science B.V. All rights reserved.