Long-term drainage, subirrigation, and tile spacing effects on maize production

Abstract

• Not a single year in 17-yr of research received normal precipitation (Apr to Sep). • Long-term data indicated narrow tile spacing reduce yearly yield variability. • Averaged by weather classifications, yield increase upto 32 % was observed with DSI. • Yields above the DSI tiles were >60 % compared to DP & ND in dry years. • Grain yield variability generally decreased from a dry to a normal year. Flooding and drought are the most damaging abiotic stresses affecting maize production in the United States. To combat these stresses, subsurface tile drainage systems were used in conjunction with water-level control structures for subirrigation of claypan soils. The objective of this research was to develop an understanding of climate and drain tile spacing on maize plant population, grain moisture, grain yield, and grain quality measured from drainage only (DO, tile spacing 6.1 and 12.2 m), drainage and subirrigation (DSI, tile spacing 6.1 and 12.2 m), non-drained delayed planting (DP), and non-drained (ND) treatments in a 17 year (2002–2018) experiment. Production data were classified into normal, wet, and dry years based on precipitation received during the 2nd quarter (Q2, Apr. to Jun.) and 3rd quarter (Q3, Jul. to Sep.). There was not a single year in 17-yr of research that received normal precipitation in Q2 and Q3 (314 ± 43 and 288 ± 34 mm) compared to 29-yr historical precipitation data. Data were collected at 3.1 m intervals above and between the 6.1 and 12.2 m tile lines and compared among drainage treatments and weather classifications (WC). A yield increase of 20–32% (2.6 to 3.9 Mg ha −1 ) with DSI above the tile compared to DP and ND treatments when data were averaged over WC. In years classified as dry-dry, yields above the DSI tiles were >60 % compared to DP and ND. Grain yield was highest for years that had less than average precipitation during Q2 classified (dry) followed by a normal or wet Q3 period. Grain yield variability among WC was between 10.8 to 16.2 Mg ha −1 for DSI-6.1 and -12.2 above the tile whereas it was between 2.9 to 15.1 Mg ha −1 for ND. Grain yield variability generally decreased from a dry to a normal year. Long-term yield data indicated that narrower drain tile spacings with subirrigation reduce grain yield variability in dry and wet environments; however, the cost-effectiveness of these systems needs to be determined.