Optimizing water requirements for green and dry fodder yield in Egyptian clover

Egyptian clover (Trifolium alexandrinum L.) holds significant importance as a leguminous forage crop in Egypt. This study aimed to investigate the optimal water requirements for Egyptian clover (cv Gemiza I) and assess water use efficiency concerning forage yield under a sub-surface irrigation system. A two-year field experiment was conducted at Gemiza Agricultural Research Station, Gharbia, Egypt, spanning the winter seasons of 2020/2021 and 2021/2022. The experimental design employed a split-plot design with three replications. The main plots consisted of four irrigation levels (40, 60, 80, and 100% of water requirements), while the subplots entailed four irrigation frequencies (3, 5, 7, and 9-day intervals). The experiment involved four cuttings of green fodder, with the first cut executed 50 days after planting and subsequent cuts taken every 30 days thereafter. The findings revealed that the water requirement for Egyptian clover varied between 2150-2250 m3/fed, contingent upon the prevailing climate and growth period. Notably, an irrigation interval of 7 days exhibited the highest forage yield when applied under a 100% irrigation level, while an 80% irrigation level demonstrated the highest water use efficiency (24.4 kg/m3 water), closely followed by the 100% irrigation level. Remarkably, the implementation of the sub-surface irrigation system with a 40% water regime, coupled with a 7-day irrigation interval, resulted in the most substantial water conservation. In summary, the utilization of the sub-surface irrigation system has demonstrated its efficacy as a viable approach for addressing the constraints posed by diminishing irrigation water availability in response to the challenges posed by climatic changes.