Tillage and Cultural Management of Irrigated Potatoes1

Abstract

AbstractMany intensively row‐cropped, irrigated soils are compacted and have slow water infiltration rates. This study was conducted to evaluate the relationship among soil compaction, water infiltration rates, and potato (Solanum tuberosum L.) yield and quality; and to determine the influence of tillage and other practices on soil compaction, water infiltration rates, and potato response. Twenty‐two commercial, irrigated potato fields were monitored and several tillage practices evaluated on soils from seven great groups. Soil compaction was evaluated by measuring penetrometer resistance. Although penetrometer resistance and water infiltration rates showed a large amount of variation in the 22 fields, they were not significantly correlated with each other. The correlation coefficient between penetrometer resistance 0.2 m below furrows and tuber yield was −0.38. Water infiltration rate was not associated with tuber yield nor quality. In the 18 fields with less than 600 g kg−1 sand, soil texture had little association with water infiltration rates, however, soil organic matter greater than 12 g kg−1 was positively associated with water infiltration rates. In the 22 fields, number of years between successive potato crops accounted for 33% of the variation in tuber yield with greatest yields when at least 4 years occurred between potato crops. In replicated tillage experiments, chiseling reduced penetrometer resistance to a deeper depth than moldboard plowing. Chiseling did not result in greater water infiltration rates, tuber yield, nor tuber quality than plowing. Chiseling and plowing in combination showed no advantage over either practice alone. Additionally, chiseling bed centers showed no yield advantage over an unchiseled check in fields that were previously plowed even though penetrometer resistance was reduced by chiseling. This study indicates that with proper irrigation management some deep tillage operations can be eliminated by many growers.