ENGINEERING FACTORS AFFECTING HYDROPONICS GRASS- FODDER PRODUCTION

Animal production and its industrial investment is overwhelmed with various problems due to the insufficient animal feeding requirements and the competition with the human crop requirements. Therefore, about third of the total cultivated area of the world is covered with the animal feeding crops. In this regard, efforts have to be carried out to develop new techniques to face this competition. The aims of this study are to: 1) establish a hydroponic unit for intensive grass fodder production; 2) study the engineering parameters affecting the efficiency of the suggested unit such as light intensity and duration of aeration, nutrient solution and its characteristics and applied amounts of water, and 3) determine the total energy requirements for improving the unit production capacity. Therefore, a closed hydroponic system was established at the Central Lab.of Agric. Eng. Agric. Eng. Dept., Faculty of Agric., Ain Shams Univ., to achieve the abovementioned objectives. However, experimental layout included lighting system to provide plants with its lighting requirement, cooling and air conditioning unit to conserve the appropriate micro-climate conditional to propagate a healthy plants and equipment, aeration and CO2 proportioning system, to enhance the root-zone media with its air balance and requirements to avoid the plant stress. Treatments of the affecting parameters could be summarized as follows: a- Engineering factors: 1) lighting time (8, 12, 16, and 24 h/day) with a fixed intensity of about 2021 lux, 2) aeration (36, 60, and 84 min/day), and 3) irrigation period (1, 2, and 3min/2h). Results of the hydroponics barley-grass fodder production under different treatments could be summarized as following: a1- The optimum lighting operating hours (2000 lux in intensity)for barley – fodder production under the suggested hydroponic system was about 12- 16 hours is the most suitable for fodder production of barley, and the vegetative growth. a2- Aeration time had a significant effect on the barley–production under the suggested hydroponics. However, there was a positive proportional relationship with all studied parameters, indicators and the aeration flow rate in terms of operating time. So, the best aeration flow rate was 3min/2h per day. b- Energy requirement: the total energy consumption for barley production under closed hydroponics systems was about 138 W/h.