Amin Reza Jamshidi; Ahmad Ghazanfari Moghaddam; Ahmad Reza Ommani
Abstract
Aeroponic planting is proved to be the one of the most efficient growing environments for many vegetable crops. In this technique, plants are cultivated in absence of soil and the required nutrients are directly supplied to the roots through a fogging system. In modern sprayers, water is atomized by ...
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Aeroponic planting is proved to be the one of the most efficient growing environments for many vegetable crops. In this technique, plants are cultivated in absence of soil and the required nutrients are directly supplied to the roots through a fogging system. In modern sprayers, water is atomized by means of ultrasound waves. The aim of the present study was to investigate the effect of ultrasound waves on the nutrient solution and on yield and some yield components of tomato grown in a vertical aeroponic planting system. The investigation was conducted using a 3×3 factorial experiment based on a completely randomized design. The considered factors were ultrasonic frequency at three levels of 50 kHz, 107 kHz and 2.1 MHz and the fogging duration at three levels of 10, 15 and 20 min. The results indicated that, at frequency of 50 MHz, the nutrient solution had the lowest EC equivalent while the pH of the nutrient solution reached its highest value at 2.1 MHz. Generally, both EC and pH value of the nutrient solution were elevated by increase in the wave frequency, but they did not show a definite trend by changes in fogging duration. The ANOVA indicated that the interaction effect of the ultrasound frequency and fogging period had significant effect on the plant height, root weight and length, fruit weight, fruit length, plant yield and system performance. In general, the measured yield components decreased as frequency of the waves increased and the best results were obtained at 50 kHz frequency and 15 min fogging period.
Li Tao; Zhang Yu-Qi; Zhang Yi; Cheng Rui-Feng; Yang Qi-Chang
Abstract
Chinese solar greenhouse (CSG) is universally applied in northern China for producing horticultural products. CSG is characterized by the unbalanced structures with an arched front roof face to the south side and a thick wall as well as back roof in the north side. Such structures affect light distribution ...
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Chinese solar greenhouse (CSG) is universally applied in northern China for producing horticultural products. CSG is characterized by the unbalanced structures with an arched front roof face to the south side and a thick wall as well as back roof in the north side. Such structures affect light distribution in the greenhouse. This study aims to investigate the light distribution properties in CSG from north to south sections, and to investigate tomato plant growth performance in the corresponding locations. Experiments were carried out in a CSG which was divided into three equal sections from north to south side. Tomato was grown in the greenhouse. Results showed that PAR intensity in the south and middle sections of CSG was permanently higher than the north section. This resulted in a distinct plant growth performance in CSG. Specifically, plants grown in the north section of CSG exhibited a shade avoidance response with stem elongation phenotype and leaf expansion. Furthermore, the north-plants showed lower leaf photosynthetic capacity which correlated with a lower total nitrogen and chlorophyll contents in comparison with the plants grown in the middle and south sections. Taken together, plants in the north section of CSG produced less total biomass than the middle and south section plants. We conclude that plant growth is not uniform in CSG due to heterogeneous light distribution which was caused by unbalanced greenhouse structures. This study may provide sound evidence for exploring a proper lighting strategy as well as fine crop management in CSG.
