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The current study was designed to evaluate the impact of using digested insect frass (DIF) as an external organic fertilizer on the sustainability of the tilapia- basil decoupled aquaponic system (DAS). The experiment consisted of two treatments; in the first treatment the digested tilapia sludge (DTS) was used solely as a nutrient source for the hydroponic unit, while in the second treatment supplementation of DIF as an external organic fertilizer (DTS+DIF) was added to the first protocol. The results showed that the concentration of K was higher in the DIF solution compared to the DTS solution. In contrast, Ca was higher in DTS solution in comparison with the DIF solution. No significant differences were detected in all the tilapia's growth parameters between both treatments. Compared to DTS treatments (0.82kg/ m2), DTS+DIF treatment (0.98kg/ m2) recorded the highest biomass of basil. Moreover, the highest chlorophyll content (SPAD) was recorded in DTS+DIF treatment compared to DTS treatment. DTS+DIF treatment produced the highest diameter of the main stem, thickness of fiber strands, phloem and xylem tissues (+16.6, +15.7, +29.3 and +40.65 ±% to DTS, respectively). On the contrary, DTS treatment had a higher vessel diameter than DTS+DIF treatment. To sum it up, it could be concluded that using digested insect frass as an external organic fertilizer may influence the succession of tilapia - basil decoupled aquaponic system. [ABSTRACT FROM AUTHOR]

Sound waves could improve the growth and increase yield. However, it could be a form of environmental stress. Therefore, the aim of this study was to investigate the effects of audible sound on the growth and endogenous hormones of strawberry plants (Fragaria_ananassa). Five endogenous hormones, namely Indole-3-acetic Acid (IAA), Gibberellin (GA), Abscisic Acid (ABA), Jasmonic acid (JA) and Zeatin Riboside (ZR) have been investigated. Plants were exposed to sound frequency of 0.1 - 1 kHz and sound pressure level (SPL) of 70 - 100 dB for 2 hours, 3 hours and 5 hours at different growth stages. Results revealed that plants had different responses to sound waves at different growth stages. Acoustic frequency could accelerate the blooming and the flowering rates in a short run. In contrast, exposing plants to sound for more than 3 hours per day for a long run more than 40 days could inhibit the growth. However, sound treatment could significantly accelerate the blooming and the flowering rates. The maximum concentration of ABA was in leaves of the treated plants for 90 days, each day for 5 hours. Whereas, mean of IAA levels in leaves of control plants was insignificantly higher than those of the treated plants for 5 hours and 2 hours after 90 days of sound treatment. Moreover, no significant difference was found in the concentration of JA in leaves between all treated plants and control plants after 75 and 90 days. In conclusion, audible sound could stimulate or inhibit the growth of strawberry plants. [ABSTRACT FROM AUTHOR]

Shading in greenhouses is a simple and cheap method usually used to reduce the intensity of solar radiation and air temperature. Moreover, combining Photovoltaic (PV) panels and crops on the same cropland could alleviate the increasing competition for the agricultural land between food and energy production. In addition, the integration of PV with greenhouses could reduce, or partially replace the energy consumption for greenhouse crop production. Therefore, the aim of this study was to investigate the shading effect of semi-transparent mono-crystalline silicon double glazing photovoltaic panels (STPV), mounted on top of an agricultural greenhouse, which occupied 20% of the roof area, on the microclimate conditions and the growth of lettuce plants inside a greenhouse. Results showed that the combination of STPV and polyethylene cover decreased the solar radiation by 35% to 40% compared to the use of polyethylene cover only for clear days which was in the acceptable range of photosynthetically active radiation for lettuce plants. Moreover, STPV shading decreases the air temperature by 1°C-3°C and had no effect in the relative humidity under natural ventilation. Furthermore, there were no significant differences (p<0.05) in the growth of lettuce plants between the shaded greenhouse by the STPV and the unshaded. Shading insignificantly increased the fresh weight, leaf area and the chlorophyll contents (p<0.05). In conclusion, the integration of STPV modules can decrease the solar irradiation and the internal air temperatures as well as generate electric energy for environmental control systems without significant influence on the growth of lettuce plants. Meanwhile, it can decrease the water consumption by decreasing the evapotranspiration rate. [ABSTRACT FROM AUTHOR]

In order to reduce the investment and operation cost of distributed PV energy system, ice storage technology was introduced to substitute batteries for solar energy storage. Firstly, the ice storage air conditioning system (ISACS) driven by distributed photovoltaic energy system (DPES) was proposed and the feasibility studies have been investigated in this paper. And then, the theoretical model has been established and experimental work has been done to analyze the energy coupling and transferring characteristics in light-electricity-cold conversion process. In addition, the structure optimization analysis was investigated. Results revealed that energy losses were high in ice making process of ice slide maker with only 17.38% energy utilization efficiency and the energy efficiency and exergy efficiency of ISACS driven by DPES were 5.44% and 67.30%, respectively. So the immersed evaporator and cointegrated exchanger were adopted for higher energy utilization efficiency and better financial rewards in structure optimization. The COP and exergy efficiency of ice maker can be increased to 1.48 and 81.24%, respectively, after optimization and the energy utilization efficiency of ISACS driven by DPES could be improved 2.88 times. Moreover, ISACS has the out-of-the-box function of ordinary air conditioning system. In conclusion, ISACS driven by DPES will have good application prospects in tropical regions without power grid. [ABSTRACT FROM AUTHOR]