Application of Earth Observation data in Agricultural drought

monitoring

Farai Kuri University of Zimbabwe

Introduction

Drought traditionally measured using rainfall data

Rainfall indices an indirect measure of drought

Remote sensing drought indices are plant based

EO is therefore a direct measure of plant performance

Objectives

To test whether and to what extent EO based drought indices can predict maize yield in Zimbabwe

Materials and Methods

Study areaStudy was based on the whole of

Zimbabwe

Data

Maize yield data courtesy of Ministry of Agriculture Mechanisation and Irrigation Development (2009-2010 & 2011-2012)

SPOT VGT NDVI long-term series AMESD Station at SIRDC and UZ (1998-2012)

Data Analysis

Calculated Vegetation Condition Index (VCI) from SPOT NDVI series

VCI<36%, Dry dekad (1), Not Dry ( 0)

Frequency of dry dekads calculated for 2009-2010 & 2011-2012

Relating Drought to Maize Yield

Regression was used to test whether and to what extent EO based dry dekads can predict maize yield.

In-Situ Maize Yield 2011-12

Frequency of Dry Dekads (2011-12 )

Results

In-Situ Maize Yield 2009-10

Frequency of Dry Dekads (2009-10)

Frequency of Dry Dekads (2009-10)

Y=1/(0.25+0.02827*2.3038x

R²=0.91P-Value=0.001

Conclusion

There is a significant relationship between frequency of RS based dry dekads and maize yield

Therefore frequency of RS based dry dekads can be used to evaluate impact of drought on yield or to estimate crop yield

Thank You