VERTICAL-FARMING IRRIGATION SYSTEM APPROPRIATE FOR LETTUCE AND CELERY CROPS

Abstract

The current experiment was carried out in greenhouse in the Central Laboratory of Agricultural Climate, Agricultural Research Center (ARC), Dokki, Giza, Egypt, to develop proper system for a Vertical Farming Irrigation System VFS for lettuce and celery crops, to get the best vegetative growth uniformity along vertical axis of planting column (tube), maximum water use efficiency (WUE) with minimum energy consumption, and maximum fresh yield per square meter floor. The effects of plant type, nozzle type, vertical-pipe nozzle position, and number of nozzles per vertical farming tube at operating pressure range of 150 to 300 kPa, on growth uniformity, fresh yield (kg/m2). Energy consumptive use and WUE were considered. The initial and operating cost, in addition to net profit of VFSare also discussed. The main results are summarized as follows: The longest vegtative growth heights of lettuce and celery, recorded by using four nozzles along the vertical tube was 24 and 46 cm at bottom layer of the planted column of the vertical farming tube(VFT), with increased percent ratios of 37.5 and 52.3% compared with using one mini sprinkler nozzle for the two crops resp.. The highest values of WUE under different number of nozzles and positions was 11.2, 8.8, and 8 kg/m3 for lettuce crop, and 12.8, 12.4, 9.75 kg/m3 for celery crop by using four, two, and one nozzle along the VFT axis, with increasing ratios of 21.5, 28.6 % for lettuce crop, and 3, 23.8% for celery crop, compared with micro and fogger nozzles resp.. The maximum energy requirements of lettuce and celery crops were 111.1, 97.2 kj/kg/y for lettuce and celery crops, by using four nozzles (75 μm-DS) along the VFT for all tested nozzle types. The best uniformity of vegetative growth was 96% by using four mini sprinkler nozzles along the VFT axis. The maximum productivities of lettuce and celery fresh yield were recorded as 14, 11, 10 kg/m2 for lettuce crop, and 16, 12.5, 11.5 kg/m2 for celery crop, for mini sprinkler, micro sprinkler and fogger nozzles resp., The maximum consumptive use of energy was 4.32kW.h/y, when using mini sprinkler nozzle, increased by 81% compared with fogger nozzle. Meanwhile the minimum consumptive use of energy was 0.6kW.h/y, when using fogger sprinkler nozzle. The maximum net profit was 1047, 1527LE/y/column for lettuce and celery crops, by using mini sprinkler (75 μm-DS) with an increase of 42.7, 41.1% for lettuce and celery crops, compared with using fogger nozzle (45 μm-DS).