The objectives of this study were to evaluate five forage crops (alfalfa (
Reducing agricultural water use while maintaining or improving economic productivity of the agricultural sector is a major challenge in arid and semiarid regions. Irrigated agriculture is the major consumer of fresh water supplies in many parts of the world, particularly in relatively arid and semiarid regions like Jordan as well as Gulf Cooperation Council (GCC) countries. The demand on scarce water resources in these countries is increasing with time for both agricultural and nonagricultural purposes.
Over recent years, severe shortages in food supplies for livestock have been experienced in Jordan and GCC countries as well as many other countries in the region, mainly, due to repeated droughts as well as shortages of water for irrigation. Many projects to produce forages have been established during the last two decades to cover some green and dry forage needs in these countries. However, scarcity of adequate fresh water supplies might pose challenges for sustainability of the field projects especially with utilizing ground water for irrigation, which is consumed in large amounts as these countries are characterized with very high rates of evapotranspiration and soils of low capacity to retain water. Therefore, methods and technologies that can contribute to improved water use efficiency and productivity merit closer consideration like hydroponic technique.
Hydroponic technique can be used for green fodder production of many forage crops in a hygienic environment free of chemicals like insecticides, herbicides, fungicides, and artificial growth promoters [
The objectives of this study were to evaluate five forage crops (alfalfa (
This study was conducted under temperature controlled conditions (24 ± 1°C) and natural window illumination at growth room of Soilless Culture Laboratory, Sultan Qaboos Center for Developed and Soilless Agriculture, Arabian Gulf University, Manama, Bahrain. A hydroponic system composed from metal frame was designed and assembled from local materials has been used in this study.
The hydroponic system is composed of two units with metal frame and six shelves each with a length of 265 cm, a width of 46 cm, and a height of 184 cm (Figure
The hydroponic system in which planting trays were stacked after seeding of different crops.
Five forage crops were evaluated in this study which were: alfalfa (
Seeds of all crops were cleaned from debris and other foreign materials. Then the cleaned seeds were sterilized by soaking for 30 minutes in a 20% sodium hypochlorite solution (household bleach) to control the formation of mould. Planting trays were also cleaned and disinfected. The seeds were then washed well from residues of bleach and resoaked in tap water overnight (about 12 hours) before planting.
Seeds of all crops were sown in the planting trays which were lined with plastic sheets and have holes at the bottom to allow drainage of excess water from irrigation. The seeding rates used in this experiment were about 300, 450, 680, 550, and 480 g tray−1 for alfalfa, barley, cowpea, sorghum, and wheat, respectively. These rates were based on seeds size and weight to have approximately the same number of plants per tray. The trays were stacked on the shelves (36 trays per 6 shelves). Trays were irrigated manually with tap water twice a day (early in the morning and late in the afternoon) at a fixed rate of 600 mL tray−1 day−1 which was enough to keep the seeds/seedlings moist. Drained water out of irrigation was collected in plastic containers which were placed under each planting tray, measured, and recorded to compute for total water use and water use efficiency.
The experiment was terminated after 8 days from seeding, where the fodder biomass was ready for harvest (Figure
Green fodder of different crops ready for harvest.
The total added and drained water out of trays throughout the course of experiment were recorded per tray every day to compute for total water use and water use efficiency.
The total water used by plants (liters/tray) was computed according to the equation:
The completely randomized design was used with four replicates. Data were statistically analyzed using analysis of variance (ANOVA) according to the statistical package MSTAT-C (Michigan State University, East Lansing, MI, USA). Probabilities of significance among treatments (crops) and LSD (
Results of this study showed that the green fodder with lush vegetation can be produced in 8 days from planting to harvest using hydroponic technique especially for cowpea and barley crops (Figure
Green fodder (fresh), dry yields, and the ratio of produced green fodder: initial planted seeds weight for the studied forage crops under hydroponic conditions.
Crop | Green fodder yield§ | Dry fodder yield§ | Moisture content | Green fodder: initial seeds wt |
Ton/ha | Ton/ha | % | ||
Alfalfa | 194 a* | 15.9 c | 91.8 a | 11.5 a |
Barley | 200 a | 34.0 a | 83.0 b | 7.0 b |
Cowpea | 217 a | 32.6 a | 85.0 b | 5.5 c |
Sorghum | 145 b | 27.6 b | 81.0 b | 4.5 c |
Wheat | 131 b | 22.9 b | 82.5 b | 4.7 c |
§Based on one production cycle (8 days).
*Means for each trait followed by the same letter are not significantly different at
Green fodder of cowpea (a) and barley (b) gave highest yields among tested crops.
Results of this study have shown that the dry fodder yield of alfalfa was greatly reduced in comparison to other tested crops (Table
Fresh green fodder to initial planted seeds weight ratio values were significantly higher in the alfalfa crop than the other four crops (11.5 for alfalfa versus 7.0 and 5.5 for barley and cowpea, resp.), with no significant differences between barley and cowpea (Table
Water is one of the basic requirements for seed germination and seedling growth as it is essential for enzyme activation, reserve storage breakdown, translocation, and use in seed germination and seedling growth [
Water use and water use efficiency of barley cultivars grown under hydroponic conditions.
Crop | Total water use | Water use efficiency | ||
Liters/tray | Liters/kg fresh matter | Kg fresh matter/m3 | Kg dry matter/m3 | |
Alfalfa | 6.4 a | 1.92 a | 521 c | 43 b |
Barley | 5.3 b | 1.55 c | 645 a | 110 a |
Cowpea | 5.9 a | 1.58 c | 633 a | 95 a |
Sorghum | 4.3 c | 1.71 b | 585 b | 111 a |
Wheat | 4.1 c | 1.80 b | 552 b | 97 a |
*Means for each trait of hydroponic barley followed by the same letter are not significantly different at
Producing green fodders under hydroponic conditions is a highly efficient process in terms of water saving when compared to field production of green fodders. When comparison is made with barley and alfalfa crops grown under field conditions, Al-Karaki and Al-Momani [
From results of this study, it can be concluded that the barley and cowpea crops showed better fodder production and WUE under hydroponic conditions than the other tested crops. However, barley crop is considered the best choice that can be used for production of hydroponic green fodder with less water consumption; especially seeds of this crop are mostly available in the market at lower price than others which reduce the cost of hydroponic fodder production.
The senior author is grateful to the Arabian Gulf University (AGU)/Bahrain for providing the facilities to conduct this research during his assignment with AGU.