Wood vinegar seed priming improves yield and suppresses weeds in dryland direct-seeding rice under rainfed production

Abstract

A declining farm labor force and increasing water scarcity worldwide are forcing rice farmers to adopt direct-seeding rice production. Under this production system, speed of germination, field emergence, and crop yield depend prominently on rice seed vigor. We hypothesized that seed priming can enhance rice seed vigor and agronomic performance. The objective of this study was to evaluate the effect of GA3 and wood vinegar seed priming on seed vigor, seedling performance, and grain yield in farmer’s fields. The experimental design was a split-split plot with four replications and planted in Thailand between April to December 2013 and 2014. Two rice cultivars (KDML 105 and RD6) were main plots; two planting methods (broadcast and row) were sub-plots, and three seed priming treatments (GA3, wood vinegar, and untreated control) were sub-sub-plots. Seed priming enhanced speed of germination and final germination percentage under both laboratory and field condition. However, soil moisture availability during flowering and seed formation significantly affected agronomic performance. Wood vinegar-primed seeds had greater shoot growth and plant population at maturity, while GA3-primed seed had more rapid germination. Yield-related agronomic performance characteristics of tillers plant−1 and yield in ton ha−1 were significantly higher for primed seed, and weed biomass was significantly reduced in 2013. Here, we show for the first time that wood vinegar is a sustainable alternative to chemicals for seed priming. Also, when water is available during flowering and seed development, wood vinegar priming increases grain yield and reduces weed pressure.