Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 2001
Publication Date: January 1, 2002
Interpretive Summary: The transition in the Southern High Plains has been from almost all graded furrow irrigation to now over 50% center pivot sprinkler irrigation and predominately low pressure spray heads often resulting in irrigation application rates in excess of the soil intake rates. Surface tillage systems from various implements are used to provide surface detention to minimize surface redistribution and/or runoff. Basin tillage, where small dikes are placed in each furrow at periodic intervals, are effective in holding both irrigations and rainfall. This study compared fully irrigated corn with limited irrigated (50% of full) using a spray system like a center pivot sprinkler for three different growing seasons. Furrow diking was effective in holding the irrigations and rainfall. A 50% reduced irrigation reduced corn yields 39% in 1997 and 22% in 1999, but a drought and disease reduced yields by 85% in 1998 when deficit irrigation was used. .Furrow diking was effective in this study, but a high residue, limited til system may have been as effective.
Technical Abstract: Corn (Zea mays L.) is a major irrigated crop in the Southern High Plains of the United States that is usually fully irrigated. The trend has been towards center pivot sprinklers equipped with low pressure, closely-spaced spray heads that have a large instantaneous application rate that can cause surface water redistribution and/or runoff. This 3-yr study (1997 through 1999) evaluated three surface tillage systems for corn under two irrigatio regimes in a semi-arid environment at Bushland, TX. The main treatments were furrow diking, clean furrows, and flat tillage. Imposed upon these tillage treatments were two irrigation regimes -- full soil water replenishment (FI) and limited irrigation (LI), which was irrigated at the same time as FI, but with one-half of the irrigation amount. Irrigations were applied using a lateral-move sprinkler system equipped with low-drift spray nozzles spaced 1.5-m apart with heads about 1.8 m above the ground and nozzled to simulate the flow rates at the outer end of a 400 m system with an irrigation capacity of 8 mm d-1. Each plot was 13.7 m wide (eighteen 0.75 m rows) with a water isolation border plot between the irrigation treatments. Yields were significantly (P<0.05) affected by year and all treatments. The 1997 and 1999 yields were similar, but the 1998 yields were reduced by a combination of drought and disease. Furrow diking did significantly increase corn yields across years and irrigation regimes in this semi-arid environment.