Direct comparisons of four irrigation systems on commercial rice farm: irrigation water use efficiencies and water dynamics

Authors: Massey, Joseph; Reba, Michele; Adviento-Borbe, Arlene; Chiu, Yin-Lin - Jack; Payne, Geoffrey

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2022
Publication Date: 3/22/2022
Publication URL: https://handle.nal.usda.gov/10113/7701194
Citation: Massey, J., Reba, M.L., Adviento-Borbe, A.A., Chiu, Y., Payne, G.K. 2022. Direct comparisons of four irrigation systems on commercial rice farm: irrigation water use efficiencies and water dynamics. Agricultural Water Management. 266:107606. https://doi.org/10.1016/j.agwat.2022.107606.
DOI: https://doi.org/10.1016/j.agwat.2022.107606

Interpretive Summary: Farmers rely on economic information when making decisions as to which production practices to employ. Although a growing body of farm-based economic research exists for different irrigation and conservation practices applicable to the production of rice, few studies have directly compared all four major rice irrigation systems under the same conditions where measurements of irrigation use, greenhouse gas emissions, yield and economics were performed. By comparing cascade flooding (CASC), multiple-inlet rice irrigation (MIRI), alternate wetting and drying (AWD), and furrow irrigation (ROW) on sixteen 40-acre fields, this two year study will help in assigning future water and methane gas credits to rice producers that participate in voluntary carbon markets.This paper reports on the irrigation results of this study; future papers will report on methane gas emissions and economics of these practices. This study found that ROW irrigation required significantly less water than CASC with no impact on average irrigation water use efficiency (i.e., bushels rough rice per inch of irrigation water applied). Field runoff was reduced using MIRI and AWD but runoff from ROW was similar to that of CASC. Coupled with the findings of others, this work shows that rice producers in the Lower Mississippi River Basin have viable options beyond cascade flooding that significantly reduce irrigation use while maintaining irrigation water use efficiency.

Technical Abstract: In response to changing production conditions and market forces, farmers continue to seek economically viable methods to produce more rice grain (Oryza sativa L.) with fewer resources. This two-year field study compared the industry-standard irrigation method, a continuous-flood delivered using cascade distribution (CASC), to two related levee-based systems (multiple-inlet rice flood distribution (MIRI) and MIRI plus alternate wetting-drying flood management (AWD) and a furrow-irrigated system (ROW). Seasonal applied irrigation, soil volumetric water holding content, water depth, grain yield and irrigation water use efficiency (IWUE) were determined for sixteen 16-ha commercial fields sown using the same rice hybrid (RiceTec XP753) each year. Runoff from one field for each system was also measured every year. Average seasonal irrigation applications were 824 ± 197 mm for CASC, 641 ± 165 mm for MIRI, 696 ± 181 mm for AWD and 631 ± 125 mm for ROW. ROW was the only system to receive less irrigation water than CASC (p=0.0314). Field soil clay contents were weakly correlated (r =-0.46) to applied irrigation. In terms of grain yield, only the 2018 ROW fields, with an average yield of 8890 ± 417 kg ha-1, differed from CASC (9991 ± 751 kg ha-1); this reduction in ROW yield was due primary to an inadvertent herbicide injury. Irrigation water use efficiency (IWUE) values were not different between irrigation treatments. Runoff from two CASC fields averaged 14% of the applied irrigation. In comparison, runoff from MIRI, AWD and ROW fields averaged of 5, 3 and 13%, respectively. Coupled with the research results of others, rice producers in the Lower Mississippi River Basin (LMRB) have viable options beyond CASC that significantly reduce irrigation use while maintaining IWUE.