SPATIAL VARIABILITY OF PLANT ANALYSIS POTASSIUM LEVELS

Plant samples were taken from a forty-acre field in an 82.5 ft. grid a t two sampling dates each rear during a three-year study. Soil samples were also taken in the same grid. Potassium (K) was analyzed in the p lant samples using both a strong acid-digest and a dilute (2%) acetic acid extraction. Plant K analyzed using both techniques were correlate d with soil test K levels. Plant K analyzed with acid-digestion was al so highly correlated with the acetic acid-extracted K. Mapping of earl y sampled plant K better represented soil K level patterns than later sampling. Plant K maps described areas of low K not represented by soi l K level maps. Plant analysis may be useful in mapping areas for rela tive K nutrition where soil K analysis is not as descriptive of plant response to fertilizer K.