Value of Using Different Vegetative Indices to Quantify Agricultural Crop Characteristics at Different Growth Stages under Varying Management Practices

Jerry L Hatfield,John H Prueger

doi:10.3390/rs2020562

Abstract

The paper investigates the value of using distinct vegetation indices to quantify and characterize agricultural crop characteristics at different growth stages. Research was conducted on four crops (corn, soybean, wheat, and canola) over eight years grown under different tillage practices and nitrogen management practices that varied rate and timing. Six different vegetation indices were found most useful, depending on crop phenology and management practices: (a) simple ratio for biomass, (b) NDVI for intercepted PAR, (c) SAVI for early stages of LAI, (d) EVI for later stages of LAI, (e) CIgreen for leaf chlorophyll, (f) NPCI for chlorophyll during later stages, and (g) PSRI to quantify plant senescence. There were differences among varieties of corn and soybean for the vegetation indices during the growing season and these differences were a function of growth stage and vegetative index. These results clearly imply the need to use multiple vegetation indices to best capture agricultural crop characteristics.

Highlights

Remote sensing of agricultural canopies has provided valuable insights into various agronomic parameters
These wavelengths are used in various Vegetative indices (VIs); it is important to examine their changes throughout the year and especially during the growing season
There is a rapid increase in the NIR values as soon as the crop begins to develop while the changes in the visible wavebands change more slowly and throughout the growing season the NIR wavelengths are more dynamic than the visible wavelengths (Figure 1)

Summary

Introduction

Remote sensing of agricultural canopies has provided valuable insights into various agronomic parameters. The advantage of remote sensing methods is the ability to provide repeated measures from a field without destructive sampling of the crop, which can provide valuable information for precision. Assessment of the impact of agriculture decisions could be enhanced through the use of field-scale monitoring to help evaluate the changes that have occurred within fields as a result of applied practices or to help guide the decisions that translate into differential applications that affect plant growth. Vegetative indices (VIs) have been developed as the combination of various wavebands and related to various canopy parameters. These have been summarized in [1,2].

Methods

Results

Conclusion