Shuyang Zhen, PhD student in the lab, was recently awarded a GA Harris research instrumentation fellowship by Decagon Devices.
This fellowship will support her research project titled ‘Using Normalized Difference Vegetation Index (NDVI) as a Proxy for Plant Size in Predictive Water Use Models to Facilitate Precision Irrigation’
Precise irrigation based on plant water needs not only allows for optimal plant growth but also conserves water and alleviates environmental pollution from fertilizer and pesticide runoff. A thorough understanding of crop-specific water requirements is essential for more efficient irrigation. However, plant water use changes on a daily basis, driven by variations in environmental conditions as well as changes in plant size over time. While environmental conditions are relatively easy to measure, direct determination of plant size is often destructive and time consuming. Remote sensing of vegetation indices, such as the normalized difference vegetation index (NDVI), provides a continuous and non-destructive method to estimate canopy size for use in water use models. My current work using Decagon NDVI sensors will develop quantitative models that predict daily water use (DWU) of bedding plant species based on environmental factors and NDVI, a proxy for plant size. The goal is to use NDVI in place of ‘crop coefficients’ which are commonly used in agronomic applications. Our preliminary data show that NDVI is highly correlated with plant growth, and a multiple linear regression model developed using only radiation and NDVI explained over 85% of variations in DWU. The inclusion of additional environmental variables or reference evapotranspiration can refine these models. Therefore, we will carry out one additional study for model validation purposes, and scale up through collaboration with commercial growers and develop study sites in nurseries.
She was awarded 6 SRS NDVI Sensors, 2 SRS PRI Sensors, 1 ProCheck, 1 PAR Sensor, 1 Pryanometer, 1 VP3 Temperature & Humidity Sensor