Effects of irrigation levels, plant densities and planting patterns on yield and water productivity of corn (KSC700) using subsubsurface drip irrigation (Tape)

In order to evaluate the effects of different levels of irrigation, crop densities and cropping patterns on corn (KSC700 variety) water use efficiency using subsurface drip irrigation system three field experiments were carried out in 2005, 2006 and 2007. in the experimental field of Agriculture Engineering Research Institute located in 400 hectare land of the Seed and Plant Improvement Research Institute in Karaj. In each experiment, experimental design was laid out as split plot design based on randomized complete blocks with three replications. In the first experimental Field, main plots were Three irrigation levels: 50%, 75% and 100% ET and sub plots were three plant densities: 65000, 75000 and 85000 plant per hectare and sub-sub plots were two planting patterns: one and two row plants per bed. Results showed that increasing the levels of irrigation from 50% to 100% of the plant water requirement, has a significant effect on yield and yield components. Results obtained from three years experiment showed that irrigation levels of 50% and 100%ET had the minimum and maximum yield values of 3.65, 12.28 and 3.58, 12.89 and 3.75, 12.56 ton per hectare in years of 2005, 2006 and 2007 respectfully. This means that corn is a plant which is highly sensitive to deficit irrigation. Calculation on water use efficiency of the all treatments showed that 12 treatments of a2b1c1, a2b1c2, a2b2c1, a2b2c2, a2b3c1, a2b3c2 and a3b1c1, a3b1c2, a3b2c1, a3b2c2, a3b3c1 and a3b3c2 located in one statistical group and 6 treatments of a1b1c1, a1b1c2, a1b2c1, a1b2c2, a1b3c1 and a1b3c2 in another statistical group with the highest and lowest walues of water use effetiency respectively. Statistical analysis also shown that three groups of a2b1c1 ΅ a2b3c1 and a3b1c1 have high water use efficiencies amoung the treatments with the values of 1.58, 1.53 and 1.58 Kg/m3 respectively which can be recommended for the areas with low and intermediate and high natural water resources for corn production in subsurface drip irrigation method.