Potential of Hyperspectral and Thermal Proximal Sensing for Estimating Growth Performance and Yield of Soybean Exposed to Different Drip Irrigation Regimes Under Arid Conditions.

Adel H Elmetwalli,Majed Alotaibi,Muhammad Usman Tahir,Wael M Hassan,Salah Elsayed,Muhammad Mubushar,Nasser Al-Suhaibani,Salah El-Hendawy

doi:10.3390/s20226569

Abstract

Proximal hyperspectral sensing tools could complement and perhaps replace destructive traditional methods for accurate estimation and monitoring of various morpho-physiological plant indicators. In this study, we assessed the potential of thermal imaging (TI) criteria and spectral reflectance indices (SRIs) to monitor different vegetative growth traits (biomass fresh weight, biomass dry weight, and canopy water mass) and seed yield (SY) of soybean exposed to 100%, 75%, and 50% of estimated crop evapotranspiration (ETc). These different plant traits were evaluated and related to TI criteria and SRIs at the beginning bloom (R1) and full seed (R6) growth stages. Results showed that all plant traits, TI criteria, and SRIs presented significant variations (p < 0.05) among irrigation regimes at both growth stages. The performance of TI criteria and SRIs for assessment of vegetative growth traits and SY fluctuated when relationships were analyzed for each irrigation regime or growth stage separately or when the data of both conditions were combined together. TI criteria and SRIs exhibited a moderate to strong relationship with vegetative growth traits when data from different irrigation regimes were pooled together at each growth stage or vice versa. The R6 and R1 growth stages are suitable for assessing SY under full (100% ETc) and severe (50% ETc) irrigation regimes, respectively, using SRIs. The overall results indicate that the usefulness of the TI and SRIs for assessment of growth, yield, and water status of soybean under arid conditions is limited to the growth stage, the irrigation level, and the combination between them.

Highlights

Irrigated agricultural lands play an important role in stabilizing global food security. these lands cover only 20% of the world’s cultivated land, they are responsible for Sensors 2020, 20, 6569; doi:10.3390/s20226569 www.mdpi.com/journal/sensorsSensors 2020, 20, 6569 approximately 40% of global food production
Fisher’s protected least significant difference (LSD) test showed that the differences in biomass fresh weight (BFW), biomass dry weight (BDW), and canopy water mass (CWM) between the 100% and 75% ETc treatments were not significant, with 50% ETc producing the lowest values for these traits at the R1 growth stage, whereas at the R6 growth stage, these traits for the irrigation regimes were ranked 100% ETc
We investigated the potential use of thermal imaging criteria and spectral reflectance indices (SRIs) for assessing the growth performance and production of drip-irrigated soybean exposed to different irrigation regimes for two years at two growth stages

Summary

Introduction

Irrigated agricultural lands play an important role in stabilizing global food security. these lands cover only 20% of the world’s cultivated land, they are responsible for Sensors 2020, 20, 6569; doi:10.3390/s20226569 www.mdpi.com/journal/sensorsSensors 2020, 20, 6569 approximately 40% of global food production. Irrigated agricultural lands play an important role in stabilizing global food security. These lands cover only 20% of the world’s cultivated land, they are responsible for Sensors 2020, 20, 6569; doi:10.3390/s20226569 www.mdpi.com/journal/sensors. Irrigated lands in developing countries account for one-fifth of the total arable area but produce three-fifths of cereal production and constitute two-fifths of all crops [1]. Moisture stress is one of the widespread abiotic factors limiting plant growth and productivity of major crops under irrigated agriculture. Abrupt climate change, high temperature and evaporation rates, and sparse and highly variable rainfall further exacerbate the drought-stress problems in irrigated agriculture, which poses a serious threat to future global food security [2,3,4]. Maximizing production per unit of irrigation water applied by shifting the irrigation strategies of crops from the paradigm of full irrigation to deficit irrigation practices is one plausible solution for addressing water shortage in irrigated agriculture [5,6]

Methods

Results

Conclusion