Effect of the degree of soil smoothing, the distance between the emitters and the Positional alternation of irrigation levels on some physical properties of the soil and the growth and productivity of corn plants

The field experiment was conducted on corn (Zea mays L.) crop during the spring season of 2020. The soil was fine clay mixed, calcareous, hyperthermic typic torrifluvent. To study the effect of different soil smoothing degrees and Positional alternation of irrigation levels on some physical properties of soil, growth and productivity of the crop. The surface drip irrigation system was used after a calibration and field evaluation of the system at an operating pressure of 150 cm and a design discharge of 8 (L.ha-1 ).The experiment included 9 treatments: PS (smoothing the soil tillage three times) and PC (smoothing the soil tillage once) representing the degree of smoothing of the soil and (0 - 100) %, (33 - 100) %, (66 - 100) %, (100) -100%) to represent the treatments of the Positional alternation of the irrigation level and (25, 30, 35) cm to represent the treatments of the distance between the emitters. The above-mentioned experimental treatments were randomly distributed according to a complete randomized block design (R.C.B.D) with three replications. Bulk density, Mean Weight Diameter, plant height, leaf area and cob weight were measured. The results showed that the PC soil smoothing treatment recorded the highest Mean Weight Diameter of 0.293 mm and the highest average leaf area amounted to 1023.56 cm2 .While the treatment of Positional alternation of the irrigation level 100-100% achieved the lowest Bluk density of 1.314 mcg. m-3 and the highest total porosity of the soil at 48.43%, as well as the highest average weight of the cob at 11.08 (ton.ha-1 ) While the treatment of the distance between the emitters 25 cm gave the highest average plant height of about 165.38 cm, according to the order