A Gaussian-Process-Based Global Sensitivity Analysis of Cultivar Trait Parameters in APSIM-Sugar Model: Special Reference to Environmental and Management Conditions in Thailand

W B M A C Bandara,Kazuhito Sakai,R H K Rathnappriya,Preecha Kapetch,Tamotsu Nakandakari

doi:10.3390/agronomy10070984

Abstract

Process-based crop models are advantageous for the identification of management strategies to cope with both temporal and spatial variability of sugarcane yield. However, global optimization of such models is often computationally expensive. Therefore, we performed global sensitivity analysis based on Gaussian process emulation to evaluate the sensitivity of cane dry weight to trait parameters implemented in the Agricultural Productions System Simulator (APSIM)-Sugar model under selected environmental and management conditions in Khon Kaen (KK), Thailand. Emulators modeled 30 years, three soil types and irrigated or rainfed conditions, and emulator performance was investigated. rue, green_leaf_no, transp_eff_cf, tt_emerg_to_begcane and cane_fraction were identified as the most influential parameters and together they explained more than 90% of total variance on the simulator output. Moreover, results indicate that the sensitivity of sugarcane yield to the most influential parameters is affected by water stress conditions and nitrogen stress. Our findings can be used to improve the efficiency and accuracy of modeling and to identify appropriate management strategies to address temporal and spatial variability of sugarcane yield in KK.

Highlights

Sugarcane plays a critical role in Thailand’s economy and has become one of the most important agricultural crops of the country [1]
Study was conducted based on crop performance of sugarcane under different environmental and management conditions in Khon Kaen (KK) in years between 1980 and 2010
R2 calculated by using the Agricultural Productions System Simulator (APSIM) simulated cane dry weight weight (CDW) and emulator predicted CDW, and GEM-Sensitivity analysis (SA)

Summary

Introduction

Sugarcane plays a critical role in Thailand’s economy and has become one of the most important agricultural crops of the country [1]. Being the major sugarcane production region of Thailand, the Northeast is responsible for 43.2% of the total produced sugarcane and 44.2% of the total sugarcane harvesting area [2]. Paddy fields that produce lower net value per hectare in the Khon Kaen (KK) area of the Northeast have been converted into sugarcane fields [3]. Increasing evidence indicates that global climate change could reduce sugarcane production. According to Preecha et al [4], climate change is the most obvious factor responsible for spatial and temporal yield variability in the Northeast of Thailand. Identification of suitable management strategies to cope with both temporal and Agronomy 2020, 10, 984; doi:10.3390/agronomy10070984 www.mdpi.com/journal/agronomy

Methods

Results

Conclusion