Curvature-based approach to determining the optimal temperature regulation ranges for greenhouse peppers across growth stages

Authors

  • Jinghua Xu 1. College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China; 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China
  • Minke Hong 1. College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China; 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China;
  • Miao Lu 1. College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China; 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China
  • Xudong Hu 1. College of Mechanical and Electronic Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China; 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China
  • Pan Gao 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China; 3. College of Information Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China
  • Jin Hu 2. Key Laboratory of Agricultural Internet of Things, Ministry of Agriculture and Rural Affairs, Yangling 712000, Shaanxi, China; 3. College of Information Engineering, Northwest A&F University, Yangling 712000, Shaanxi, China; 4. Shaanxi Engineering Research Center of Agricultural Information Intelligent Perception and Analysis, Yangling 712000, Shaanxi, China
  • Qingxue Li 5. Information Technology Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China

Abstract

In protected agriculture, extreme temperatures can cause irreversible damage to crops, making temperature regulation a critical component of greenhouse environmental management. The dynamic optimization of the temperature ranges serves as the core strategy to enhance production stability. Consequently, identifying the optimal temperature ranges is pivotal for maximizing greenhouse production efficiency. This study proposes a novel method for determining the optimal regulation ranges throughout the multiple growth stages of greenhouse-grown peppers, incorporating curvature theory. A nested experiment was designed to obtain the photosynthetic rate (Pn) of peppers during the multiple growth stages under variable temperature, CO2 concentration, and photosynthetic photon flux density. A photosynthetic rate prediction model was then constructed using a backpropagation neural network optimized by a genetic algorithm, with an R2 of 0.9812 and an MSE of 1.35 μmol/(m2·s). The prediction model was subsequently discretized and applied to calculate the Gaussian response surface of Pn. Finally, the U-chord algorithm and the random restart hill-climbing method were employed to precisely define the boundaries of the temperature regulation ranges. Practice demonstrated that the average dry weight of pepper fruits in the experimental group was 96.83% higher than that of the no-operation regulation group and 243.65% higher than the fixed threshold group. This method not only enhances pepper growth but also exhibits superior regulatory tolerance. Its innovative temperature regulation strategy provides crucial technical support and establishes a reliable decision-making basis for the precise environmental management of greenhouse crops in protected agriculture.      

Keywords: photosynthetic rate prediction model; curvature theory; target boundary; greenhouse temperature regulation; machine learning

DOI: 10.25165/j.ijabe.20261902.10170

 

Citation:  Xu J H, Hong M K, Lu M, Hu X D, Gao P, Hu J, et al. A curvature-based approach to determining optimal temperature regulation ranges for greenhouse peppers across growth stages. Int J Agric & Biol Eng, 2026; 19(2): 65–77.

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Published

2026-05-21

How to Cite

(1)
Xu, J.; Hong, M.; Lu, M.; Hu, X.; Gao, P.; Hu, J.; Li, Q. Curvature-Based Approach to Determining the Optimal Temperature Regulation Ranges for Greenhouse Peppers across Growth Stages. Int J Agric & Biol Eng 2026, 19, 65-77.

Issue

Vol. 19 No. 2 (2026): IJABE

Section

Animal, Plant and Facility Systems

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