Assessing the Performance of the WOFOST Model in Simulating Jujube Fruit Tree Growth under Different Irrigation Regimes

Tiecheng Bai,Nannan Zhang,Benoit Mercatoris,Youqi Chen

doi:10.3390/su11051466

Abstract

Cropping system models are widely employed to evaluate plant water requirements and growth situations. However, these models rarely focus on growth studies of perennial fruit trees. The aim of this study was to evaluate the performance of the WOFOST (WOrld FOod STudies) model in simulating jujube fruit tree growth under different irrigation treatments. The model was calibrated on data obtained from full irrigation treatments in 2016 and 2017. The model was validated on four deficit percentages (60%, 70%, 80%, and 90%) and one full irrigation treatment from 2016 to 2018. Calibrated R2 and RMSE values of simulated versus measured soil moisture content, excluding samples on the day of irrigation and first day after irrigation, reached 0.94 and 0.005 cm3 cm−3. The model reproduced growth dynamics of the total biomass and leaf area index, with a validated R2 = 0.967 and RMSE = 0.915 t ha−1, and R2 = 0.962 and RMSE = 0.160 m2 m−2, respectively. The model also showed good global performance, with R2 = 0.86 and RMSE = 0.51 t ha−1, as well as good local agreement (R2 ≥ 0.8 ) and prediction accuracy (RMSE ≤ 0.62 t ha−1) for each growth season. Furthermore, 90% of full irrigation can be recommended to achieve a balance between jujube yields and water savings (average decline ratio of yield ≤ 3.8%).

Highlights

Jujube (Zizyphus jujuba Miller) fruit is rich in vitamin C, amino acids, carbohydrates, and minerals, and has been widely used in traditional foods, food additives, flavorings, and raw materials in traditional Chinese medicine [1], as well as medicinal supplements [2]
The aim of this study was to evaluate the performance of the WOFOST (WOrld FOod STudies) model in simulating jujube fruit tree growth under different irrigation treatments
How to use water resources effectively and how to implement precision agricultural irrigation are important for this water-deficient area, which are important parts of sustainable agricultural production

Summary

Introduction

Jujube (Zizyphus jujuba Miller) fruit is rich in vitamin C, amino acids, carbohydrates, and minerals, and has been widely used in traditional foods, food additives, flavorings, and raw materials in traditional Chinese medicine [1], as well as medicinal supplements [2]. The southern region of Xinjiang Uygur Autonomous Region has the highest output, of about 3.26 million tons, and supplies high quality jujube because of the large temperature difference and sufficient light in this region In this arid and warm-temperate region, average annual rainfall ranges from 77 mm to 106 mm, and crop growth highly depends on irrigation. Crop growth models derived from mathematical descriptions have become more advanced They are widely applied in agricultural production management and societally relevant applications such as climate change responses [3,4,5,6,7,8], crop yield predictions [9,10,11,12,13], and understanding crop responses in field experimentation and the environment [14,15,16]. Other models, such as SWAP (Soil, Water, Atmosphere and Plant) [23], AquaCrop (Crop-water productivity model) [24] and CropSyst (Cropping Systems Simulation Model) [25], are constantly being added for different crops and purposes

Objectives

Methods

Results

Conclusion