CORN PHOSPHORUS AND POTASSIUM UPTAKE IN RESPONSE TO SOIL COMPACTION

Soil compaction by heavy axle load farm machinery can inhibit optimum plant growth. Uptake of essential nutrients, like P and K, is influenced by soil compaction. This study describes plant P and K accumulation from a compacted Webster (fine-loamy, mixed, mesic Typic Haplaquolls) soil. Whole plant samples of corn (Zea mays L.) were collected at the 75% vegetative-tassel (VT) stage from 0, 9, and 18 Mg axle load subsoil compaction treatments, each with secondary interrow surface soil compaction of 0- or 4.5-Mg axle loads. Subsoil compaction reduced P and K uptake as much as 22% during seasons when June and July rainfall was less than average. Subsoil compaction of 18 Mg did not consistently reduce P and K uptake more than did 9 Mg subsoil compaction. Surface soil compaction also reduced P uptake, but to a lesser extent than did subsoil compaction. Overall P and K uptake, across atl treatments, was enhanced when June and July precipitation was average or wetter than the 30-yr average.