Study on plant adaptation and effects of irrigation and NPK elements on growth and yield parameters in Gingiber officinale R. in Pakdasht and Lahijan regions

To evaluate the plant adaptation and effects of irrigation cycles and NPK elements on growth and yield parameters of Zingiber officinale R., a split-plot experiment was conducted as a randomized complete block design with nine treatments and three replications in two regions including Pakdasht (Tehran province) and Lahijan (Gilan province) in 2021. The experimental factors included irrigation cycle at three levels (4 (V1), 6 (V2), and 8 (V3) days) as the main factor and NPK elements at three levels (N300P100K200 (F1), N350P150K250 (F2), and N250P50K150 (F3) (kg.ha-1)) as the sub-factor. The results showed that the irrigation×NPK effects was significant on plant height, number of leaves per plant, leaf area, number of branches per plant, leaf area index, fresh and rhizome dry weight, and rhizome yield at the 1% probability level and on stem diameter at the 5% probability level in Pakdasht region. The V1F2 treatment was the best one in this region. In Lahijan region, the irrigation×NPK effects was significant on number of leaves per plant and rhizome yield at the 1% probability level and on plant height and stem diameter at the 5% probability level. The best result in Lahijan was obtained in the V1F2 treatment. Also, in terms of leaf area, number of branches per plant, and leaf area index, V1 and F2 was the best treatments in Lahijan. Fresh and rhizome dry weight had the best results in the V2 and F2 treatments. Overall, the studied traits in Lahijan climate were superior to Pakdasht climate and every 4 days irrigation for Pakdasht and every 6 days for Lahijan had the best results.