Response of Maize (Zea mays L.) Growth and Yield to Irrigation Regimes and Different Tillage Systems under Dongola Area Conditions- Northern State (Sudan)

Abstract

Field experiments were conducted for two consecutive summer seasons; 2005/06 and 2006/07, at Dongola area- Northern State. The objectives were to investigate the effect of irrigation regimes and tillage practices on maize (Zea mays L.) growth and yield in addition to their effects on some of the soil physical properties and weed control. Irrigation water amounts were determined using FAO Penman- Monteith equation (1998) for estimating crop evapotranspiration (ETc). Three levels of ETc were used; 100%, 75%, and 50% ETc. Tillage practices constituted three land preparation systems; disc ploughing (20 cm depth) followed by disc harrowing and levelling, chisel ploughing (30 cm depth) followed by disc harrowing and levelling, and no tillage. Three irrigation intervals were imposed; 10, 15, and 20 days. The application of irrigation treatments was started at the third irrigation. The treatments were arranged in a split-split-plot design with three replicates. Irrigation water amounts had no significant effect (P ≤ 0.05) on all the tested parameters in both seasons except for soil moisture content at soil depths of 0-25, 25-50, and 50-75 cm where it was significant (P ≤ 0.01) in both seasons. The irrigation water amount of 75% ETc compared with the other treatments gave the tallest plants throughout the different growth stages of maize and the highest values of leaf area index, stover yield, and grain yield in both seasons. The irrigation water amount of 50% ETc gave the highest values of plant population and field water use efficiency in both seasons. The results obtained revealed that tillage practices induced significant variations (P ≤ 0.01) on soil dry bulk density only at soil depth of 0-25 cm in both seasons. Tillage practices had no significant effect (P ≤ 0.05) on the number of broadleaf weeds and the total number of weeds, but they significantly affect (P ≤ 0.01) the number of grasses in both seasons. The tilled treatments reduced the total number of weeds in both seasons compared with no-tilled treatment. Plant dry mass had no significant effect (P ≤ 0.05) due to tillage when checked early in the season. However, tilled treatments recorded higher values of plant dry mass than no-tilled treatment. There were significant differences on plant height due to tillage when checked at 30 days (P ≤ 0.05) and 45 days (P ≤ 0.01) after sowing in both seasons. Tillage practices had significant effects (P ≤ 0.01) on leaf area index, soil moisture content at the different soil depths, cob length, grain yield, and field water use efficiency in both seasons. Also, tillage practices had significant effects (P ≤ 0.05) on plant population, number of seeds/cob, and stover yield in both seasons. Disc ploughing treatment gave the highest values of all mentioned parameters in both seasons. Irrigation intervals had a significant effect (P ≤ 0.01) on plant height in both seasons. There were significant differences (P ≤ 0.01) due to irrigation intervals on soil moisture content at soil depths of 0-25 and 75-100 cm in one of the two seasons. Irrigation intervals showed significant differences (P ≤ 0.01) on grain yield and field water use efficiency in both seasons. Also, irrigation intervals had significant effects (P ≤ 0.05) on the number of seeds/cob and stover yield in both seasons. For all mentioned parameters irrigation interval every 10 days gave the highest values in both seasons. There were significant differences (P ≤ 0.05) due to treatments interactions mean in one of the two seasons on plant height at 75 days after sowing, cob length, and harvest index for interaction effect of irrigation water amounts and tillage treatments, on plant height at 75 days after sowing, number of seeds/cob, grain yield, harvest index, and field water use efficiency for interaction effect of tillage and irrigation intervals treatments, and on grain yield for irrigation water amounts, tillage practices, and irrigation intervals treatments combination. Also, some of the treatments interactions gave significant differences (P ≤ 0.05) on soil moisture content in one of the two seasons or in both seasons at some of the different soil depths tested in the experiments.