Overcoming liabilities of loose sand such as scarce nutrients and low water retention remains an agricultural challenge. “plot-and-berm” (P&B) agroecosystems, situated in dune fields, consist of sunken agricultural plots between 1 and 5 m high berms, overcome these constraints. The plots situated over a 1–3 m deep and perched groundwater table ease and control access for crop roots and/or human water extraction and may make this agrotechnology resilient to short-term drought. Refuse and organic material enrich the sandy soil in plots. The agroecosystems require significant resources for construction and maintenance. The earliest agroecosystems are Early Islamic (nineth-early twelfth centuries ad) ones along Mediterranean coastal dune fields of Israel. Arabic literature reviews have not found descriptions of P&Bs, but this effort may be an original type of mawāt (Arabic: “dead”) unowned wastelands reclamation, an important issue in Islamic economic history. Partially active and similar P&B agroecosystems along the southern Mediterranean region in Northern Sinai/Gaza Strip, Algerian Sahara, and Iberia yield fruit and vegetable crops and date back to the Middle Ages. Their concept may have originated from the Early Islamic ones. Being in stressed environments, P&B agroecosystems can be re-established into groundwater-efficient community-farming econiches that can nurture geoethical relations between science and local populations.