Assessment of the Role of Low Irrigation and Change in Plant Density on Water Use Efficiency and Yield and Yield Components of Maize (S.C 704)

Water is the first and the most important limitation in increasing agricultural production. Topical root dryness is a new method of low irrigation, which improves the water utilization efficiency, without significantly reducing the yield of the plant. Maize is a plant that is very sensitive to plant densities, and if the density is low, then the factors of exploitation are not optimized. On the other hand, excessive plant density causes flower sterility and reduced grain yield. Therefore, this experiment aims to investigate the role of low irrigation and plant density changes on the water use efficiency and grain yield components of corn.

The experiment design was implemented as a split plot design in a randomized complete block design with three replications. The main plots Include: 1- full furrow irrigation (control), 2- furrow irrigation in the form of a fixed and 3-variable furrow irrigation. Sub plots include different planting densities: 65,000, 75,000, and 85,000 plants per hectare.

The results showed that different low irrigation methods had significant effects on ear tick length, number of seeds per ear, 1000 grain weight, grain yield, biological yield, harvest index and water use efficiency. Differences among plant densities in terms of ear tick length, number of seeds per ear, 1000 grain weight, grain yield, biological yield and water use efficiency were significant. The highest grain yield was observed in full irrigation (6858 kg ha-1) and at a density of 85,000 plants per hectare (6159 kg ha-1). The highest water consumption efficiency was obtained in irrigation as variables (17.33%) and at 85,000 plants per hectare (15.52%). Single plant yield decreased at 85 thousand plants, but this deficit was compensated by increasing plant number per unit area and grain yield increased. Single plant yield increased by 65 thousand plants. But because of the less plant per unit area, its yield decreased. Grain yield increased by about 14% in irrigation of one side of the variable compared with one in the constant. Changes in performance components are expected to trigger these changes. With increasing plant density per unit area, water use efficiency also increased, which is due to more cover and less shade and evaporation from the ground. Plant density per unit area also affects water use efficiency by reducing evaporation and increasing the share of transpiration that results in high yield. Water use efficiency in treatments with intermittent furrow irrigation was higher than constant furrow irrigation.

The full furrow irrigation (control) method was able to obtain the highest yield and grain yield components. As a result, in one irrigation in between fixed and variable, 25 and 12% reduction in yield was observed compared to full irrigation, respectively.