Water table management systems can be designed to alleviate soil water excesses and deficits, as well as reduce @entity1507 leaching losses in tile discharge. With this in mind, a standard tile drainage (DR) system was compared over 8 years (1991 to 1999) to a @entity23 ( @entity23 ) system on a low-slope (0.05 to 0.1%) Brookston clay loam soil (Typic Argiaquoll) in southwestern Ontario, Canada. In the @entity23 system, tile discharge was controlled to prevent excessive drainage, and water was pumped back up the tile lines (subirrigation) to replenish the crop root zone during water deficit periods. In the first phase of the study (1991 to 1994), continuous @entity4336 ( @entity2829 .) was grown with annual @entity1568 (N) fertilizer inputs as per local soil test recommendations. In the second phase (1995 to 1999), a @entity1460 ( @entity1460 .)- @entity4336 rotation was used with N fertilizer added only during the two @entity4336 years. In Phase 1 when continuous @entity4336 was grown, @entity23 reduced total tile discharge by 26% and total @entity1507 loss in tile discharge by 55%, compared to DR. In addition, the 4-year flow weighted mean (FWM) @entity1507 concentration in tile discharge exceeded the Canadian drinking water guideline (10 mg N l(-1)) under DR (11.4 mg N l(-1)), but not under @entity23 (7.0 mg N l(-1)). In Phase 2 during the @entity1460 - @entity4336 rotation, @entity23 reduced total tile discharge by 38% and total @entity1507 loss in tile discharge by 66%, relative to DR. The 4-year FWM @entity1507 concentration during Phase 2 in tile discharge was below the drinking water guideline for both DR (7.3 mg N l(-1)) and @entity23 (4.0 mg N l(-1)). During both phases of the experiment, the @entity23 treatment caused only minor increases in @entity1507 loss in surface runoff relative to DR. Hence @entity23 decreased FWM @entity1507 concentrations, total drainage water loss, and total @entity1507 loss in tile discharge relative to DR. In addition, @entity1460 - @entity4336 rotation reduced FWM @entity1507 concentrations and total @entity1507 loss in tile discharge relative to continuous @entity4336 . @entity23 and crop rotations with reduced N fertilizer inputs can thus improve the quality of tile discharge water substantially.

Water table management reduces tile @entity1507 loss in continuous @entity4336 and in a XXXX - @entity4336 rotation.

@entity1568 :: ('MESH:D009584', 'Chemical') :: ['nitrogen'] @entity2829 :: ('4577', 'Species') :: ['Zea mays, L'] @entity4336 :: ('381124', 'Species') :: ['corn'] @entity1507 :: ('CHEBI:48107', 'Chemical') :: ['nitrate'] @entity23 :: ('MESH:D007174', 'Disease') :: ['CDS', 'controlled tile drainage/subirrigation'] @entity1460 :: ('3847', 'Species') :: ['soybean', 'Glycine max L., Merr']
@entity1460 :: (3847,Species) :: ['soybean']
