Tomas Persson
Seniorforsker
(+47) 466 30 485
tomas.persson@nibio.no
Sted
Særheim
Besøksadresse
Postvegen 213, NO-4353 Klepp stasjon
Sammendrag
Greenhouse cultivation can help meet food demand in a growing and increasingly urbanised population. Reliance on fossil-fuel heating and natural ventilation often makes conventional greenhouses energy- and carbon-inefficient. Closed greenhouses address these limitations through resource recycling and energy recovery. While a centralised environmental control system (ECS) integrating climate control and heat harvesting has shown potential to improve greenhouse crop performance at high latitudes, its year-round energy use and energy-related carbon footprint reduction potential remains insufficiently quantified. This study extends an existing dynamic greenhouse climate model to incorporate a novel centralised ECS integrating air recirculation, heating, cooling, and heat harvesting in (semi-)closed greenhouses. The model was validated using experimental data from Norway, reproducing temperature and relative humidity with RMSEs of 1.40–1.63 °C and 7.60–8.55%, respectively. Energy use and tomato yield were predicted with relative errors of 3.8–8.4% and 1.6–4.2%, respectively. Scenario simulations under Norwegian conditions showed that (semi-)closed greenhouses with heat harvesting can reduce fossil fuel use by over 80% while increasing tomato yields by 15–41% relative to open greenhouses, driven by changes in CO2 concentration and temperature following reduced ventilation and heat recovery. The performance of a fully closed greenhouse relying solely on on-site cold storage is constrained by cooling capacity and buffer size, particularly during summer; adding a supplemental cold energy source such as surface water can improve its performance. Despite heat harvesting, a residual boiler heating demand of 3–10% remains. Further gains in energy efficiency and crop performance may be achieved through optimised climate control.
Sammendrag
Data Availability Statement: No datasets were generated or analysed during the current study.
Forfattere
Mohammad Tirgariseraji A. Pouyan Nejadhashemi Mahmood Sabouhi Sabouni Yaghoob Jafari Tomas Persson Alisher Mirzabaev Alireza Nikouei Kieron Moller Naser Shahnoushi ForoushaniSammendrag
Food production is the primary source of nitrogen pollution, which has significantly impacted the nitrogen cycle and exceeded the nitrogen-safe operation space of the planet. The objective of this study is to assess the effectiveness of the Nitrogen Regulatory Policy (NRP) in reducing nitrogen fertilizer use under population pressure for meat, dairy, wheat, and potatoes in the Zayandeh-Rud River basin, Iran. The methodology of this study involves two main components. First, an elasticity criterion was formulated to assess the trade-off between nitrogen fertilizer use and food production capacity. This criterion integrates optimized cropland, the Block of Distributed Calories (BDC), and nitrogen fertilizer use, with food production capacity quantified in terms of the BDC at its optimal level. Second, the simulated distribution of the elasticity criterion was analyzed using Simulation and Econometrics to Analyze Risk (Simetar), defining elastic and inelastic zones to capture the variability in the trade-off under different conditions. The results of this study identified key factors influencing the elastic and inelastic ranges of the elasticity criterion, including technological change, the weight of diet components in dietary preferences, and the diminishing returns of the NRP. The NRP solution aims to reduce nitrogen fertilizer use by targeting a lower application range. It addresses the challenges of fertilizer management under population pressure, specifically for farming systems in the Zayandeh-Rud River basin operating at the ‘diminishing marginal production’ stage. The trade-off between livestock and non-livestock diet components enhances nitrogen fertilizer efficiency under population pressure as long as livestock components remain within the elastic zone and non-livestock components stay within the inelastic zone. The novelty of this study lies in the introduction of the elasticity criterion for nitrogen fertilizer use under population pressure. This innovative metric highlights the risk of ineffective trade-offs between food production capacity and nitrogen fertilizer adjustments, offering a crucial tool to guide sustainable agricultural practices within the defined criterion ranges.
