The mean DLI in the greenhouse was significantly lower than GREENBOX, with average values of 14.52 and 10.44 mol/m2·d over summer and winter, respectively. Thus, the light conditions in the GREENBOX could be consistently regulated at the grower’s discretion for optimal growth. Although the DLI in the GREENBOX showed a slight decline over each growing cycle due to the depreciation of light bulbs , the variations were so small that open field or greenhouse structures could not replicate due to changes in weather conditions and length of daytime over the year. The temperature regimes inside GREENBOXES were in the optimal range to sustain lettuce growth over summer and winter without significant variation over the day . However, the greenhouse temperatures exceeded the optimal temperatures with a significantly higher variation, especially during summer . The main heating source in the GREENBOX is the lighting element. Due to the insulation from external weather fluctuations provided by the warehouse and the thermally insulated walls of GREENBOX structure, the seasonal and diurnal temperature variations were minimal over the year compared to the greenhouse . The GREENBOX structures also sustained ambient humidity conditions between 40% – 60% for most of the time, higher in summer and lower in winter. In any case, the relative humidity was below 70% and thus did not affect crop growth. The average relative humidity was lower over summer and winter in GREENBOX, and higher in greenhouse in the summer and winter,with a much higher variation over the day in the greenhouse .
The fluctuations are significantly higher and immediate to weather events such as cloud cover and precipitation as the greenhouse is directly exposed to external elements. Overall, the lettuce crops’ environmental conditions over the summer and winter indicated that GREENBOX technology could provide the desired environment to sustain growth year-round, with lower fluctuations and higher consistency . The biomass and productivity data collected at harvest found that measured variables were similar across growing locations,mobile grow rack with slightly higher values over summer than winter, as presented in Table 2. The dry weight at harvest was higher in the greenhouse than GREENBOX .We found the wet weight is consistently higher in summer than in winter.Wet weight and dry weight represent the cumulative amount of gas exchange in photosynthesis and evapotranspiration over the growing cycle. The productivity across growing locations was not significantly different in the same season but was higher over the summer than in winter . There were subtle differences among seasons, but such differences did not cause a significant difference in crop growth and productivity over growing locations. The results indicate that the GREENBOX provided the required environmental conditions to sustain lettuce crop growth from seedling to full bloom and ready for consumption. The growth in the GREENBOX followed similar patterns to greenhouse crop production . Furthermore, the environmental conditions provided in both growing locations were within the optimal range for crop sustenance. Environmental parameters were more consistent and controllable in the GREENBOX. The temperature variations over summer were almost five times higher in the greenhouse than GREENBOX . However, the variations over winter were not that drastically variable over both growing locations. We attribute the higher variability in the greenhouse over summer due to the lower capability of the greenhouse climate control in response to the high variation in solar energy.
Summer has the longest duration of light over the year, and despite using shade curtains to control the intensity of sun rays hitting the crops, the trapped infrared rays led to higher temperatures in the greenhouse . Care must be taken to maintain relative humidity at an optimum level, as high relative humidity can lead to fungal disease, and if relative humidity is too low it can cause stunted growth. The GREENBOX and greenhouse provided these conditions comfortably during growth over the summer and winter. As expected, the humidity over winter in both growing locations was lower than in summer. Variations in relative humidity over winter were significantly higher in the greenhouse than GREENBOX . The variation over winter was higher in the greenhouse than GREENBOX . The relative humidity trends in the greenhouse were directly affected by external weather, sometimes rising to almost 96% during a rainstorm and decreasing to lower values when there is no rain for an extended time. By virtue of the GREENBOX having an independent lighting source, crop production is not dependent on sunlight and variation on cloud covers and weather events. There are advantages to growing crops in a controlled environment. The GREENBOX is not as drastically affected by the external weather due to the sole reliance on an artificial lighting source for its photosynthetic needs. Lettuce crop production times vary year-round due to differences in daylight length over the year. However, year-round lettuce production is possible by maintaining a consistent DLI, lighting intensity, and time length. Controlled environment agriculture can achieve uniform crop and extension ofgrowing seasons by controlling environmental and cultural factors. Future GREENBOX trials include a heater/air conditioners combination to precisely modulate temperature levels and a combination of humidifier/dehumidifier to control moisture levels at optimal levels. While the productivity was similar in the GREENBOX and greenhouse, there was a noticeable difference in productivity and wet weight at harvest between the summer and winter. We attribute this phenomenon to a higher evapotranspiration rate and subsequent growth due to higher temperatures.
The GREENBOX primary heating source was the lighting element; future iterations may include a heat pump to supplement heat sources to combat colder conditions. In response to the growing awareness of the carbon footprint associated with increased food miles, a growing social movement has been to eat locally sourced food . As a result, there is a growing consumer base of locavores willing to pay a premium for locally grown produce that is hyper-fresh. The total supply chain of food needs 4200 miles of movement, and 1020 miles is the final average food miles traveled in the United States. Therefore, ebb and flow table a decrease in food miles traveled can be linked to a lower carbon footprint and alleviate the effects of climate change. When placed in strategic areas, GREENBOX can potentially reduce the food miles problem by making fresh produce more accessible. Scaling up localized high yield controlled environment agricultural setups can help increase the resilience of the food supply systems. With GREENBOX technology, one can design plant factory setups closer to the point of consumption such that the produce can be quickly harvested and sold, saving resources on preservation and transportation, along with space saved for inventory. There is promising potential for the GREENBOX in leafy green crop production in urban areas. Consumption growth and increasing populations will mean that global food demand will comfortably exist for forty years at a minimum. Over twenty years, a five-fold increase in sales has been noted for salad-mixes in the United States. As of 2018, worldwide controlled environment agriculture was valued at 26.8 billion USD, with a projected 9.19% growth between 2020-2025. Leafy vegetables such as lettuce are also gaining popularity as they represent practical and convenient foods with high nutritional content. Clinical investigations have demonstrated a direct inverse link between a lower incidence of chronic disease and high consumption of green leafy vegetables, owing to it being a good source of antioxidants, phytochemicals, vitamins, and minerals. GREENBOX can potentially serve as an excellent resource for educational purposes. Students from various disciplines such as engineering, life sciences, and technology can learn of all ages. Urban areas can easily meet the resources requirements for a viable urbanagricultural setup, such as light, heat, carbon dioxide, water, space, and airflow. GREENBOX may use water from the city water supply but can use greywater or stormwater streams in cities. There are many potential avenues in urban areas that GREENBOX can be used such as underground unused tunnels and basements, flat, unused rooftops, vacant spaces in occupied buildings such as atriums, open planned spaces and corridors, and abandoned vacant spaces within buildings . There is great potential for incorporating CEA setups in urban areas as more than 60% of construction is pending to match the projected urban area to be developed by 2030. There are new commercial establishments in this field, such as Gotham Greens claims that their crop production is 30 times more compared to traditional methods with locations in New York and Chicago and are rapidly expanding across the United States. There are many goals future iterations of GREENBOX can aim for as a CEA setup. An ideal CEA setup must strive for a decrease in variation in environmental parameters. An ideal CEA setup should be designed to be upgraded with the least cost and minimum modification and maintenance. An ideal CEA setup should strive for the right balance between automation , labor-saving measures, and job security. CEA setups have the advantage of a small physical footprint. We may also include different types of crop growth such as spinach, pakchoi, kale, swiss chard, among many others. We may also use fruiting plants such as cherry tomatoes, strawberries, among many others.
Our current study used warehouse conditions for GREENBOX crop production; we can also use other areas such as abandoned mills, strip malls, or shipping containers. The current project was a pilot study as a proof of concept, and therefore we used commercially available materials to assemble the GREENBOX. Future trials may include materials that use low-cost thermally insulated prototypes and are explicitly designed for this purpose. Workers often suffer in heavy, especially those who are using. The equipment with the nature of the seismic events of significant health problems was encouraged to study and analyze and measure the vibration of workers in this area, which is one of the most interesting engineering applications. This physical factor that acts on the human body is vibration which transmits the mechanical energy from sources of oscillation. Vibration can effect in different way to the operators; machine operators are always meeting two different types of vibration: vibrations effect to the whole-body produce through seat or floor and feet, and vibration which produced by the hand-grip. Both forms of vibration can effect on the operator which reduce on his job performance and health. Farm tractors and other earth-moving equipment contribute to some of the most common, prolonged, and severe occupational exposures of vehicle vibration among equipment operators. Disturbances in finger blood flow, and in neurological and motor functions of the hand and arm can produce by excessive exposure to hand-transmitted vibration. It has been estimated that 1.7% – 3.6% of the American and European workers are exposed to potentially harmful hand transmitted vibration. The European list of recognized occupational diseases inserted these disorders. The term “handarm vibration syndrome” is a case resulting with the exposure of machincal vibrating transmitted through hand and arm that affect in disorders vascular, neurologic, and musculoskeletal. Although that are a very important issue and serious in many nation, small concern are paid to that. Nearly any user of agricultural tools is exposed to “whole body vibration “or” hand arm vibration”. Even people on work that seems simple careers such as cutting the grass in the garden by the machine or driving the tractor in the orchards can be exposed to sudden vibration; especially vibration resulted from the handle to the driver’s hands. This vibration was known as a trouble. Vibration in tractor depends on many factors velocity of tractor, topography of field, tractor condition and design tractor and configuration which is by dynamic response. Vibration power resulting to use a lot of different types of agriculture’s tools can cause hand vibration in the tractor driver, and used density of these tools can affect the nervous system such as changes in tendons, tissue diseases, muscles, bones and the vascular injury which also results lower blood flow that is the most common complication of this type of vibration which can produce white fingers. The vibration entering to the operator hand not only causes health problems, but also lowers the driver working skills and sensation; using this type of tractors is very common in small and medium orchards and vegetable farms; these tractors considered easy to use and the cheapness, and these types known as small size tractor or single-axle tractor can be used in many agricultural operations like harvesting, plant protection, irrigation, threshing, and transportation.