Spatial variability of plant analysis potassium levels

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