Furrow Water Intake Reduction With Surge Irrigation or Traffic Compaction

Abstract

Excessive water intake and related deep percolation losses have not been considered a major limitation for growing season irrigation applications through graded furrows on slowly permeable soils. However, applications of 100 to 200 mm (4 to 8 in.) are common for the first irrigation after primary tillage; and before furrow surface consolidation reduces intake during succeeding applications. Both furrow compaction by wheel traffic and surface consolidation by surge irrigation have potential as relatively low cost methods of reducing intake, thereby reducing percolation losses and conserving irrigation water. Field studies were conducted in the Southern High Plains on a slowly permeable Pullman clay loam (Torrertic Paleustoll) to compare the effects of furrow compaction by wheel traffic and surge flow on irrigation intake during the first irrigation after primary tillage. Where 0.75 m (30 in.) spaced furrows had been tilled to the 200 mm (8 in.) depth; one traffic pass with a 6 mg (13,000 lb) tractor, increased bulk density from about 1.0 to 1.4 mg/m3 (62 to 87 lb/ft3). During the first irrigation after primary tillage, the effect of furrow traffic compaction reduced irrigation water intake (application less runoff) by 18 to 27%. Surge flow, without furrow traffic, reduced intake by about the same amount while plant available soil water storage to the 1.8 m (6 ft) depth was reduced by only 5 to 10%.