Effect of potassium nitrate, licorice extract and planting date on field emergence and growth of maize (Zea mays L.) in spring season

Abstract

Low temperature and high relative humidity in the spring season led to decrease of field emergence ratio and growth in maize. Planting dates and seeds stimulation can be appropriate fix. Field experiment was conducted in the two spring seasons of 2022 and 2023. Randomize complete block design with split-plot arrangement and four replications was used. Planting date treatments (February 15th, March 1st and 15th and April 1st, 15th) were placed in main plots. Seeds stimulation treatments (potassium nitrate 6 mg L−1 + licorice extract 6 g L−1 as well as treatment of soaking with distilled water only) were placed in subplots. Seeds stimulation (potassium nitrate+licorice extract) or planting date of February 15th were superior at traits of field emergence ratio, days to 75% tassel and silk, days to physiological and full maturity, leaf area index, plant dry weight and crop growth rate in both seasons. Interaction treatment of stimulation (potassium nitrate+licorice extract) and planting date of February 15th excelled at traits above (86.2 and 86.9%), (87.0 and 86.0 day), (91.2 and 91.0 day), (113.5 and 110.0 day), and (113.5 and 110.0 day), respectively. It can be concluded that seed stimulation contributes to enhancing plant growth in adverse conditions in the spring season by increasing the field emergence ratio and plant growth rate over a wide range of environmental conditions. Determining the appropriate planting date contributes to utilizing the prevailing environmental conditions and raising the efficiency of metabolic processes in increasing plant dry weight. Also, using natural materials to stimulate seeds to withstand adverse conditions, which boosts the concept of sustainable agriculture. It can be recommended soaking the seeds with potassium nitrate+licorice extract when planting in the spring season.