FURROW COMPACTION FOR CONTROLLING EXCESSIVE IRRIGATION WATER INTAKE.

Irrigation of moderately permeable soils by the graded furrow method can result in excessive water intake and major losses to profile drainage. A field study was conducted on Olton clay loam to evaluate effects of increasing furrow spacing and compaction on irrigation water intake, evapotranspiration, estimated profile drainage losses, and corn yields. Wide spacing of furrows had very little effect, while wheel compaction reduced the average water intake and estimated profile drainage losses. Irrigated furrows were compacted as a separate tractor pass prior to the preplant irrigation, and effects remained through the growing season. The reduced water intake with furrow compaction did not affect corn grain yields. Irrigation of compacted furrows permits the use of a fixed pumping rate to irrigate a larger area by reducing profile drainage and increasing field application efficiency.