Location: National Peanut Research LaboratoryTitle: Corn yield response to irrigation level, crop rotation, and irrigation system
Submitted to: Journal of Crop Improvement
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2021
Publication Date: 11/16/2022
Citation: Sorensen, R.B., Lamb, M.C., Butts, C.L. 2022. Corn yield response to irrigation level, crop rotation, and irrigation system. Journal of Crop Improvement. https://doi.org/10.1080/15427528.2021.2005212.
Interpretive Summary: Overhead sprinkler irrigation systems (pivots) are the most common irrigation type in the Tri-state area (AL-FL-GA) because they are quick to assemble (with specialized equipment), durable, and have owner familiarity with operation and maintenance. These overhead systems can cover large areas reducing the cost per area basis. However, pivots are relatively expensive to install on small areas or in odd-shaped fields where the system may not be able to make a complete circle and must backtrack to start over. Since these pivot systems travel in a circle, there are non-irrigated corners or edges of the field where the system may not travel. Another concern with overhead sprinkler systems is the loss of water not reaching the intended target due to drift and evaporation and not being available for crop use. In contrast, drip irrigation may include precise placement of water and chemicals, lower labor requirements, and reduced runoff and erosion compared with overhead sprinkler systems. A drip system has the capability of frequently supplying water to the root zone thereby reducing the risk of cyclic water stress typical of overhead irrigation systems due to travel times from beginning to end of a cycle. Popularity of drip systems, especially for field crops, is lacking in part due to the non-familiarity of installation, management, and overall operation of these systems. Drip irrigation systems for this research are described as follows: surface drip systems (SDI) had drip tubing placed on the soil surface; deep subsurface drip (SSDI) irrigation had drip tubing buried 10- to 12-inches below the soil surface; and shallow subsurface drip irrigation (S3DI) had drip tubing buried about 2-inches below the soil surface. SDI is traditionally used for high value vegetable/truck crops were the drip tubing is replaced seasonally. SSDI is considered permanent and typically not removed until the life span of the tubing has been reached. S3DI can be used with strip tillage production systems, may last up to five years or longer depending on crop rotation Due to the expense of installing drip systems, it is assumed that most drip systems are limited to use on high value vegetable crops. However, economic evaluations showed that SSDI for field crops would be more profitable in fields under a 65-ac threshold because it requires a lower initial investment per unit land area and has lower pumping costs compared to fixed or towable center-pivot systems. SSDI systems have a near-static cost per area compared with overhead sprinkler systems (center pivots), where cost per area decreases as the length of the pivot system increases. With both drip (SSDI and S3DI) and sprinkler systems available to the grower, decisions on which system to install are determined by installation expense, field size and geometry, and final crop yield. The grower needs long term yield data to determine which type of irrigation system to install, especially on smaller fields or awkward field geometries. It would also be helpful to know if a specific crop rotation would increase corn yield. The objectives of this research were to determine the long-term yield of corn to 1) three types of irrigation systems, 2) three various irrigation rates, and 3) four crop rotations over an 18-year period. All crops were managed using best management practices for maximum yield such that irrigation rate and crop rotation were the main treatments. All crop rows were planted on a 3-ft spacing oriented east and west, perpendicular to the travel of the lateral and parallel drip tubing. Prior to installation of any irrigation systems (2001) the entire field area was conventionally tilled consisting of subsoiling (once), moldboard plowing (once), disking (twice), field cultivating (once), and rototilled to establish seedbeds. After plot establishment year, the dryland, sprinkler, and S3DI (dri
Technical Abstract: Long term corn yield data would be useful in determining crop rotation, irrigation system selection, and irrigation level for maximum production and economic sustainability. Research was conducted at the USDA/ARS National Peanut Research Laboratory’s Multi-crop Irrigation Research Farm in Shellman, GA (84°36”W, 30°44”N) on a Greenville fine sandy loam (fine, kaolinitic, thermic Rhodic Kandiudults) soil with 0 to 2% slope. This long-term study (2001 to 2018) compared three irrigation systems, four corn crop rotations, and various irrigation levels on corn yield. Irrigation systems were sprinkler, deep subsurface drip (SSDI), and shallow subsurface drip (S3DI) irrigation compared with a dryland control. Irrigation levels were 100, 66, 50, 33, and 0% of estimated water use. Crop rotations were 1) corn-corn-peanut, 2) corn-peanut, 3) cotton-corn-peanut, and 4) corn-corn-cotton-peanut (corn = Zea mays L.; cotton = Gossypium hirsutum L.; peanut = Arachis hypogaea L.). There were yield differences due to crop rotation; however, the differences were not consistent across years, irrigation levels, or irrigation systems. Sprinkler and S3DI systems had greater yield (12010 kg/ha) than SSDI system (9659 kg/ha) at the 100% irrigation level when averaged across all years or rotations. In wet years, there was no difference in yield due to irrigation level. In dry years, irrigation level influenced corn yield for sprinkler and SSDI but not always for S3DI. When selecting an irrigation system, long term yield should not be the only criteria but should consider crop rotation, field size, system installation cost, irrigation system controls, and crop and irrigation system management.