Response of Yield and Yield Component of Maize to Different Levels of Irrigation and Plant Density Uner Surface Drip Irrigation System

In order to evaluate different levels of irrigation and plant density, a field study was laid out as split plot design based on randomized complete blocks with three replications in single and two-row cultivation uner surface drip irrigation system. Main plots were four irrigation levels: 50, 75, 100 and 100% of water requirement and sub plots were three plant densities: 65000, 75000 and 85000 plants per hectare and sub-sub plots were two planting patterns, one and two row plant per bed. The results showed that grain yield increased with increasing water consumption, so that in the first and second years, 125% ET and 50% ET treatment, with averages of 12.41, 3.46 and 13.28, 3.37 tons per hectare, respectively, have the highest and lowest yields. Compared to 100% of water requirement, in 125% of water requirement with 25% increase in water consumption, grain yield increased by 21and 18% for the first and second years, respectively. But in the 50% of water requirement, with 50% reduction in water consumption, grain yield decreased significantly by 64% for the first and second years. The highest grain yield, plant height, ear height, number of seeds per row, number of grain rows, 1000-seed weight and plant biomass were obtained at a planting density of 65,000 plants per hectare. Under interaction of levels of irrigation and planting arrangement, The highest yield and yield components of maize were observed in 125% of water requirement and in two-row cultivation. Due to the limitations in the country's water resources and by dividing the country's regions into three regions: low water, medium and high water  It can be suggested that in low water areas, 75% of the water requirement with a density of 75,000 plants per hectare and single row planting arrangement, in areas with moderate water resources, 100% of water requirement with a density of 75,000 plants and two-row planting arrangement and in areas with rich water resources, 125% of the water requirement with a density of 85,000 plants per hectare and a two-row crop arrangement should be used as a proposed model to achieve maximum yield and yield components of corn.