On-farm response of inbred and hybrid rice cultivars to furrow irrigation

Authors: SPENCER, DAVE - Mississippi State University; GORE, JEFFREY - Mississippi State University; MILLS, BRIAN - Mississippi State University; GHOLSON, DREW - Mississippi State University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2023
Publication Date: 9/25/2023
Citation: Spencer, D.G., Gore, J., Mills, B.E., Gholson, D.M. 2023. On-farm response of inbred and hybrid rice cultivars to furrow irrigation. Agronomy Journal. https://doi.org/10.1002/agj2.21453.
DOI: https://doi.org/10.1002/agj2.21453

Interpretive Summary: Alternate wetting and drying (AWD) water management is an alternative to the traditional use of continous flood in the drill-seeded, delayed-flood rice production system. AWD reduces irrigation demand, but land preparation is time consuming and labor intensive. This research was conducted to determine whether rice grown in a furrow-irrigated (ROW), raised seedbed system, also known as row rice, has similar water requirements and profit expectations to AWD. The effects of growing either inbred or hybrid rice under AWD or furrow irrigation management on water applied, grain yield, and net returns were investigated for three years on paired production fields in the Delta region of Mississippi. For inbred and hybrid rice lines the water applied averaged 587 and 565 mm, respectively, and did not differ between ROW and AWD production. Compared to AWD, furrow-irrigating inbred rice cultivars maintained yield in two years of the study and decreased yield by 16% in one year of the study. Conversely, seeding hybrid rice in ROW systems reduced yield by 7% in all years of the study. For both inbred and hybrid rice cultivars, transitioning from AWD to furrow irrigation decreased the average net returns $9.80 and $124.02 per hectare, respectively, and ranged from +$94.48 to -$281.98 per hectare over three years and three rice prices. These findings indicate that transitioning from AWD to ROW rice will not likely impact water demand but will introduce increased agronomic and economic risk to the production system.

Technical Abstract: Alternate wetting and drying (AWD) water management reduces irrigation demand compared to a continuous flood in the drill-seeded, delayed-flood rice (Oryza sativa L.) production system, but land preparation is time consuming and labor intensive. This research was conducted to determine whether rice grown in a furrow-irrigated (ROW), raised seedbed system has similar water requirements and profit expectations to AWD. The effects of growing either inbred or hybrid rice under AWD or furrow irrigation management on water applied, grain yield, and net returns were investigated on paired production fields in the Delta region of Mississippi. For both inbred and hybrid rice lines, water applied averaged 587 and 565 mm, respectively, and did not differ between ROW and AWD production (p > 0.05). Compared to AWD, furrow-irrigating inbred rice cultivars either maintained or decreased yield 16% (p = 0.0207). Conversely, seeding hybrid rice in ROW systems reduced yield 7% regardless of year (p = 0.0083). For both inbred and hybrid rice cultivars, transitioning from AWD to furrow irrigation decreased the average net returns $9.80 and $124.02 ha-1, respectively, and ranged from +$94.48 to -$281.98 ha-1 over 3 years and three rice prices. Transitioning from AWD to an ROW rice will likely have no effect on freshwater demand but will introduce substantial agronomic and economic risk to the production system.