BACKGROUND: Drought stress is one of the most important factors limiting the agricultural products. The use of humic acid and Titanium dioxide nanoparticles led to keep crop production under water stress conditions. OBJECTIVES: Current research was conducted to assess effect of Nano titanium dioxide and Humic acid on Corn yield under water deficit stress. METHODS: This study was done according combined analysis split-split plot experiment based on randomized complete blocks design with four replications along two agronomic years (2021-22 and 2022-23). The main factor included different Irrigation regime (I1: Control or normal irrigation, I2: Cut irrigation at ear emergence, I3: Cut irrigation 7 days after ear emergence) and sub factors consisted different level of Humic acid foliar spraying (H1: Control, H2: 1000 ppm.ha-1, H3: 2000 ppm.ha-1, H4: 4000 ppm.ha-1) 60 days after planting. Also different level of Nano titanium dioxide (T1: Control, T2: 0.02% ha, T3: 0.04% ha) belonged to sub-sub plot. RESULT: The results of analysis of variance showed that the triple interaction of irrigation regime, humic acid, and titanium dioxide on the number of grains per ear and grain yield was significant at 1% probability level. Also, the interaction of irrigation regime and humic acid on the number of grain per row, 1000-grain weight, carotenoids, leaf relative humidity, Dityrosine and Dihydroxyguanosine was significant. The highest grain yield (9094.1 kg.ha-1) was obtained under normal irrigation conditions with the application of 2000 ppm.ha-1 of humic acid and 0.02% ha of Nano Titanium Dioxide, which showed an increase of about 38.5% compared to the treatment of cut irrigation at ear emergence stage and nonuse humic acid and Nano Titanium Dioxide (5579 kg.ha-1). Under limit irrigation conditions, the concentration of biochemical biomarkers such as Dityrosine and Dihydroxyguanosine increased, but their levels were reduced by the application of humic acid and Nano Titanium Dioxide under stress conditions. CONCLUSION: According to the results obtained from this study, use of 2000 ppm.ha-1 humic acid and 0.02% ha Titanium Dioxide Nanoparticles as foliar sprays is recommended under water deficit stress conditions led to produce economic yield and advised to producer in studied region.
Jalakani et al. (Tue,) studied this question.