Water and nitrogen impacts on water use, forage yield and quality of annual ryegrass

In this study, the effects of different irrigation levels (0 (rainfed), 25, 50, 75 and 100%) and nitrogen doses (100, 150 and 200 kg ha^- 1) on water use, morphological characteristics, herbage yield and herbage quality of annual ryegrass were investigated. Experiments were carried out in randomized blocks-split plots experimental design with 3 replications in 2021-2022 and 2022-2023 for 2 years. Applied irrigation water quantities varied between 190 and 762 mm in 2021-2022 and between 204 and 816 mm in 2022-2023. Crop water consumptions (ETc values) were calculated as between 179 and 872 mm in the first year and 170-916 mm in the second year. The highest green-dry herbage yields, plant height, plant diameter and number of tillers were obtained from IT100xN200 treatments, and the highest protein yield was obtained from IT50xN200 treatments. While ADF, NDF, ADL, crude fiber and crude ash contents increased, crude protein content decreased with increasing irrigation water levels. Crude protein and crude ash contents increased, and cell fiber content decreased with increasing nitrogen doses. Mineral contents of ryegrass increased with increasing irrigation water levels and nitrogen doses. It was concluded based on present findings that IT100xN200 treatments could be applied for herbage yield and mineral contents and IT50xN200 treatments could be applied for protein yield and quality herbage production in ryegrass production.