Response of Ryegrass to Nitrogen Fertilizer under Two Irrigation Systems

Abstract

Abstract The objective of this study was evaluation the effectiveness of the some irrigation systems, and determining the best nitrogen fertilizer level and its effect on some growth characteristics and quality of Italian ryegrass seeds. A field experiment was carried out in two locations, the first is the Khan Atshan pasture station in the Karbala, and the second is the Dikkah pasture station - Khanaqin affiliated to the Forestry and Desertification Control Department - Ministry of Agriculture during the fall season 2021-2022. The experiment was carried out according to a randomized complete block design, in split plots arrangement, with three replications. The main plots included two irrigation systems (solid set sprinkler irrigation and free flow irrigation), and the sub plots included the addition of four levels of nitrogen fertilizer in the form of urea (46% N): 0, 15, 30, and 45 kg N h-1, The results showed that the solid set sprinkler irrigation system was significantly superior to the free flow irrigation system in achieving the highest average of the total chlorophyll content in the leaves 17.69 % and 9.63%, crude protein in the cereal 20.54% and 23.60 % and the percentage of carbohydrates in the cereal 13% and 14% for both experimental location, while the free flow irrigation system was significantly superior in achieving the highest mean of the flag leaf area 4.32% and 5.08% and the dry weight of the plant 13.55% and 46.67% for both location. The results also showed that increasing the added nitrogen fertilizer up to the level of 45 kg h-1 led to a significant increase in each of the flag leaf area cm2 and the total chlorophyll content in the leaves mg g-1, percentage of crude protein in cereals, dry weight of plants, percentage of ash in cereals, and percentage of carbohydrates in cereals in two experiment location.