Optimal planting density: effects on harvest time and yield
An analysis was performed to identify the optimal planting density and time of harvest for a lettuce crop (Lactuca sativa L.) and the economic benefit of this approach was evaluated. Top Projected Canopy Area and crop Head Size information were combined with a hexagon tiling algorithm to find the range of possible planting densities that could accommodate plants of progressive sizes. A model was used to predict expected mean mass (g head‑1) of a head lettuce over time. The analysis combined this information to generate a yield rate (g m‑2 d‑1) function. By finding the maximum of this function, the optimal harvest time in days after transplant was discovered. Under the assumption that the plants were harvested as soon as they reached canopy closure and began to crowd, the optimal harvest time for the crop occurred on day 15.6 after transplant, the optimal density was 58.9 plants m‑2, the predicted head mass was 38.7 g, and the maximum yield rate was 145.9 g m‑2 d‑1. Economic analysis, considering the trade-offs between operational costs and revenues associating time of harvest and plant density, indicated that the optimal production time was at 15.6 days after transplanting (DAT) and plant density is 58.9 plants m‑2, based on all the assumption and production system considered in this study.
Shasteen, K.C., Seong, J., Valle De Souza, S., Kubota, C. and Kacira, M. (2023). Optimal planting density: effects on harvest time and yield. Acta Hortic. 1369, 41-48
planting density, yield, computer vision, baby greens, plant crowding, profit optimization