Drip fertigation technique with planting models strategies trigger grain filling, endogenous hormonal changes and...

Mulch drip fertigation strategies have been widely adopted to improve maize productivity in semi-arid regions. However, the impact of the mulch-based drip fertigation on endogenous hormone dynamics in crops and grain yield has not been fully elucidated, and the biochemical mechanisms underlying yield improvement under different drip fertigation strategies remain unclear. Grain filling has a significant impact on maize production. The aim of this study was to explore the effect of plastic film mulching materials on maize grain filling under a drip fertigation strategy, and the relationship between this effect and changes in endogenous hormones. This study compared biodegradable film mulching (BM) with soil crust ridges (SR) under high (H), medium (M), and low (L) drip irrigation conditions, and measured that the grain filling characteristics and changes in grain endogenous hormones in various parts of maize ears during the growth stage. The results showed that the grain filling rate, dry matter plant^-1, hormone changes, yield components, water use efficiency (WUE), and ET of maize under the BMH treatment were significantly higher than those under the SR treatment. BMH treatment significantly increased soil water storage significantly increased plant hormone contents such as abscisic acid (ABA), indole-3-Acetic acid (IAA), and zeatin + Zeatin Riboside (Z+ZR), and decreased the evolution rate of gibberellins (Gas) and ethylene, thereby increasing maize yield. These results indicate that BMH treatment improved the filling process, soil respiration rate, WUE, yield, and yield composition of maize. High drip fertigation with BM or SR treatment significantly affected endogenous hormone changes, thereby regulating the activity grain-filling period (AGP), maximum grain-filling rate (G_max), maximum grain weight (W_max), mean grain-filling rates (G_mean) and occurrence time of maximal filling rate (T_max) of maize. In addition, high drip fertigation and the BM strategy significantly increased soil water storage and soil respiration rate during the grain filling period. Based on these results, we conclude that BMH significantly improved soil water storage, thereby regulating the maize grain filling rate, which was significantly correlated with the balance of endogenous hormones in the grains.