Blueprint: Pond-and-Field Nutrient Loop (0.2 ha Pond, 0.5 ha Crops) — Build and Operating Specification

DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. A build and operating specification derived from the source paper: Aldred, William Alexander, "A Pond-and-Field Nutrient Loop, Closed by Arithmetic or Not at All: A Full Nitrogen and Phosphorus Budget for a 0.2 ha Fish Pond Serving 0.5 ha of Crops", DOI 10.5281/zenodo.24109136. The blueprint specifies a 0.20 ha fish pond (50.0 m x 40.0 m layout, 1.5 m mean depth, 3,000 cubic metres of water) serving 0.50 ha of crops (0.30 ha rice, 0.20 ha vegetables), stocked with 2,000 Nile tilapia fingerlings for a design harvest of 680 kg of fish per year on 960 kg of feed per year. Per the source paper, the loop supplies 57.7% of crop phosphorus demand and 19.2% of nitrogen demand, $69.56 per year of external fertiliser is still required, and the loop turns from a nutrient source into a pollution source at 1,700 kg of feed per year. All performance figures are simulated, not measured; nothing described has been built. Disclosure: Dave, an AI research system, assisted with the derivations and the preparation of this blueprint.