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Holt, N., & Shukla, S. (2016). Transforming the Plasticulture Production System through Novel Bed Geometry Design. Transactions of the ASABE, 59(3), 993–1003.
Abstract: Raised-bed plasticulture with drip irrigation is used worldwide for growing high-value crops, especially vegetables. This high-input, intensive system must become more efficient to meet food demands while reducing its environmental footprint. Futuristic tall and narrow compact beds were designed with an aim to improve the plasticulture system by increasing or maintaining yield while decreasing system input requirements. Using a whole-systems approach, compact geometries were evaluated on an example crop, eggplant (Solanum melongena L.), in the ecologically sensitive but highly productive sub-tropical Everglades region of Florida. Two compact beds, 61 cm (width) x 25 cm (height) and 45 cm x 30 cm, were evaluated against a conventional short and wide bed, 91 cm x 15 cm. The conventional bed used two drip tapes for irrigation and fertigation. The compact beds needed only one tape but produced equivalent yields as the conventional bed. Irrigation, nitrogen, and phosphorus application rates were respectively reduced by 50%, 14%, and 19% in the compact beds. Water and nutrient productivities with the compact beds increased by at least $43 per 10 kL irrigation, $6 per kg nitrogen, and $8 per kg phosphorus applied, representing respective gains of 92%, 11%, and 8% over the conventional bed. Productivity increases highlight how compact beds can make plasticulture more efficient. Shifting to compact beds also brings non-water co-benefits, including reductions in the system's production costs by $560 to $670 ha(-1), carbon footprint by 5% to 10% (reduced fumigant and plastic usage), agricultural plastic waste, and potential detrimental impacts from changed climate. Compact beds provide flood and disease protection by decreasing impervious (mulched) surface area and having extra bed height above the ground. Use of compact beds at the study farm would decrease rainfall intensity in the row middles by 34% and increase the farm's soil water storage capacity by 52% (1.4 cm). Increased storage and infiltration of rainfall will decrease flooding frequency and runoff volume, thereby reducing peak flows in downstream environments. Compact beds also have an added economic benefit for farmers who pay to lease land, as production can be increased through a higher plant population density without changing total mulched surface area. A cultural shift to taller and narrower compact beds makes plasticulture more sustainable as water, nutrient, cost, and energy inputs are reduced without sacrificing yields. Compact beds provide the impetus to transform plasticulture to a futuristic, further-optimized system that is more automated (e.g., chemigation), less labor intensive, and better adapted to climate change for continued economic and environmental viability.