Transforming the food-water-energy-land-economic nexus of plasticulture production through compact bed geometries
2017
Holt, Nathan | Shukla, S. | Hochmuth, George | Muñoz Carpena, Rafael | Ozores-Hampton, Monica
Raised-bed plasticulture, an intensive production system used around the world for growing high-value crops (e.g., fresh market vegetables), faces a water-food nexus that is actually a food-water-energy-land-economic nexus. Plasticulture represents a multibillion dollar facet of the United States crop production value annually and must become more efficient to be able to produce more on less land, reduce water demands, decrease impacts on surrounding environments, and be economically-competitive. Taller and narrower futuristic beds were designed with the goal of making plasticulture more sustainable by reducing input requirements and associated wastes (e.g., water, nutrients, pesticides, costs, plastics, energy), facilitating usage of modern technologies (e.g., drip-based fumigation), improving adaptability to a changing climate (e.g., flood protection), and increasing yield per unit area.Compact low-input beds were analyzed against conventional beds for the plasticulture production of tomato (Solanum lycopersicum), an economically-important crop, using a systems approach involving field measurements, vadose-zone modeling (HYDRUS), and production analysis. Three compact bed geometries, 61cm (width)× 25cm (height), 45cm× 30cm, 41cm× 30cm, were designed and evaluated against a conventional 76cm× 20cm bed. A two-season field study was conducted for tomato in the ecologically-sensitive and productive Everglades region of Florida. Compact beds did not statistically impact yield and were found to reduce: 1) production costs by $150–$450/ha; 2) leaching losses by up to 5% (1cm/ha water, 0.33kg/ha total nitrogen, 0.05kg/ha total phosphorus); 3) fumigant by up to 47% (48kg/ha); 4) plasticulture's carbon footprint by up to 10% (1711kg CO2-eq/ha) and plastic waste stream by up to 13% (27kg/ha); 5) flood risks and disease pressure by increasing field's soil water storage capacity by up to 33% (≈1cm); and 6) field runoff by 0.48–1.40cm (51–76%) based on HYDRUS model simulations of 10-year, 2-h storm events in other major tomato production regions of California and Virginia.Re-designing the bed geometries in plasticulture production systems to be more compact is an example of win-win production optimization not only for traditional farms in rural areas but also for urban and peri-urban farms which are located closer to city centers. Compact beds could enable more plants per unit area, thus requiring less land area for the same production. Needing less area facilitates urban and peri-urban farming where land values can be high. Urban and peri-urban farming has several benefits, including reductions in transportation energy as production is closer to market and the ability for city wastewater to be reused for irrigation instead of freshwater withdrawals. Compact beds allow plasticulture to have smaller water, chemical, energy, carbon, waste, and economic footprints without impacting production. Improving agricultural systems in this way could enhance economic and environmental viability, which is essential for a sustainable food-water-energy-land-economic nexus.
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