Impact of alternative irrigation practices on rice quality

BACKGROUND AND OBJECTIVES: Current global concerns about water scarcity present a need to investigate more water‐efficient rice production methods. Alternate wetting and drying (AWD) is fast emerging as a water‐saving irrigation practice, but its effects on rice quality are largely unknown. To ascertain the impact of water‐saving irrigation practices on rice quality, three irrigation treatments, namely continuous flooding with cascade delivery (four fields); continuous flooding with multiple‐inlet delivery (four fields); and AWD with multiple‐inlet delivery (four fields), were established on 12 production‐sized (16.2 ha) fields in 2017. FINDINGS: Results of rice quality evaluations showed that irrigation treatment had a significant (p < 0.05) effect on chalkiness. Samples harvested from the AWD fields had slightly greater mean chalkiness (5.6%) than samples harvested from the two continuously flooded fields (5.1–5.2%). Milling yields were not affected (p > 0.05) by irrigation treatments. The average milled rice and head rice yields across irrigation treatments were 73% and 59%, respectively. Regarding pasting properties, while peak and breakdown viscosities were not affected (p > 0.05) by the irrigation treatments, setback viscosity (SB), which is often linked with cooked rice texture, was impacted. Among the irrigation treatments, mean SB was least for the AWD treatment (146 cP), while the mean SB for the continuously flooded fields was similar at 168–169 cP. CONCLUSIONS: In summary, the use of AWD with multiple‐inlet delivery did not impact milling yields of rice relative to the conventional practices of continuous flooding. However, rice harvested from the AWD treatment fields had slightly greater chalkiness and lesser SB. SIGNIFICANCE AND NOVELTY: This study addresses a gap in literature concerning the impact of emerging water‐saving irrigation techniques, especially AWD as it involves subjecting rice to a certain level of water stress, on rice grain quality characteristics.