The Effect of Different Irrigation Systems, Discharge, and Irrigation Intervals on Green Onion Growth and Yields

An experiment was conducted in the field of the University of Baghdad in spring season of 2015 In loamy sand soil to evaluate the effect of different irrigation systems, discharge and irrigation intervals on green onion growth and yield, using locally combine implement which used for installation subsurface irrigation pipes and surface drip irrigation. Subsurface drip irrigation system and surface drip irrigation system as main plot treatment, three levels of discharge included 2.5, 3.0 and3.5 Lhr represented subplot treatment and two levels of irrigation intervals included: 4 days and 8 days represented sub subplot treatment were used in this study. Root diameter, stem diameter, green weight, dry weight, and stem length were measured. Nested design under randomized complete block design (CRBD) with three replications was used in this experiment. Least significant differences (L.S.D) at 0.05 levels were used to compare the mean of treatments. The results were showed the following: Subsurface irrigation was superior in getting higher 78.6 gm dry weight and 232.2 gm green weight and 31.8 mm stem diameter and root diameter stood 45.2 mm and stem length stood 55.3 cm comparing with other treatments. 3.5 L/h discharge was superior in getting the highest 81.8 gm dry weight, 249.4 gm green weight, stem length stood 70.8 cm, root diameter stood 45.4 mm and stem diameter stood 32.6 mm comparing with other treatments. 4 days irrigation interval was superior in getting higher 80.2 gm dry weight, 231.4 gm green weight, root diameter stood 46.3 mm, stem diameter stood 32.7 mm and stem length stood 55.3 cm comparing with other treatments. Triple interaction between subsurface irrigation system, 3.5 L / h discharge and4 days irrigation interval was superior in getting the highest dry weight stood 86.4 gm, green weight stood 252.3 gm, stem length stood 78 cm, root diameter stood 50.6 mm and stem diameter stood 35.3 mm comparing with other interactions treatments.