Ali El Battay (Dr.)Yap Tsong ShiuanKamaruzaman SIJAM (Dr.)Mazlan HASHIM (Prof. Dr.)

PROACTIVE APPROACH TO USE HYPERSPECTRAL REMOTE SENSING FOR CROP

BIOTIC STRESS DETECTION

“proactive” means controlling a situation by causing something to happen rather than waiting to respond to it after it happens. RS data are the mirror of what happened on Earth surface.

Using PRS, the change detected in RS data are deliberately induced and the Earth surface is intentionally modified in such a way that the electromagnetic signal reflects new information inaccessible by conventional RS techniques.

Early detection and treatment of cash crop diseases can prevent unnecessary losses and significantly increase crop yield

The induced spectral response will aid in early detection of cash crop diseases through synchronization of remote sensing data acquisition with the routine farming practices and/or environmental fluctuations

CONVENTIONAL METHODS

Visual Approach

Requires years of knowledge and experience

Time consuming

Labour intensive

Difference in perception among individuals

REMOTE SENSING

Thermology Detect transpiration Passive Sensitive to environment

Chlorophyll fluorescence imaging Chlorophyll efficiency Artificial illumination

Reflectance imaging Satellite or airborne

platform Expensive

To prove the occurrence of pre-symptom stage (spectral) of ralstonia solanacearum infection in cucumber plant

To determine the possibility of inducing a measurable spectral change by using nutrient, light exposure and water stress during the pre-symptom stage

Crop Type: Cucumber (Cucumis sativus L.)

Pathogen: Ralstonia solanacearum (Bacterial Wilt)

Stimuli: Nutrient content, water content, light

exposure

Cucumber (Cucumis Sativus L.) is one of the most widely produced vegetable in the world.

An annual, creeping herb, up to 5 m long

It is grown for the immature fruits which are used as a salad vegetable, pickles and sometimes boiled in stews

A gram-negative, plant pathogenic, soil bacterium

The cause of bacterial wilt in a very wide range of potential host plants

Common crop hosts are:potatoes, tomatoes, aubergine, banana, geranium, ginger, tobacco, sweet peppers, olive, etc.

Transmission is through contaminated:tools, machinery, handlers, water, soil and seed

Severe rapid wilting of leaves

Chlorotic or stunted with adventitious roots on the stem

Glistening beads of dark gray slimy ooze from the infected xylem in stem cross sections

Bacterial streaming of fine, milky white strands from xylem vessels occurs when stems are cut and placed in water

Non-inoculated cucumber under normal optimal conditions

Inoculated cucumber under normal condition

Non-inoculated cucumber + manipulated nutrient

Inoculated cucumber + manipulated nutrient

Non-inoculated cucumber + manipulated light exposure

Inoculated cucumber + manipulated light exposure

Non-inoculated cucumber + manipulated water content

Inoculated cucumber + manipulated water content

Spectroradiometer measurement

Determination of pre-symptom stage of ralstonia solanacearum in cucumber

Quantitative estimation using vegetation indices

Quantitative estimation using vegetation indices

Detection of spectral signature changes in the pre-symptom stage

Normal Condition

Nutrient Stress

Water Stress

Non-inoculated Seed

Light Stress

Backup

Inoculated Seed

Normal Condition

Nutrient Stress

Water Stress

Light Stress

Backup

(a)ASD FieldSpecPro Spectroradiometer connected to the Panasonic Toughbook.

(b) Fiberoptic attached to pistol grip with 8˚ foreoptic.

White referenceDark currentRaw DN (10 times)Constant lightingConstant angleAccompanying image

and notesθ

Normalised Difference Vegetation

Index

Most widely used vegetation index. Difference between the high chlorophyll absorption and the reflection of leaf cellular structure

Structure Insensitive

Pigment Index

Estimate the ratio of carotenoids to chlorophyll-a.

Triangular Vegetation

Index

Total area of triangle formed by green, red and infra-red bands gives information on chlorophyll absorption and leaf tissue abundance

Nitrogen Reflectance

Index

Estimate nitrogen content in the target which is related to the chlorophyll-a content.

Modified Chlorophyll Absorption Ratio Index

Measures the chlorophyll absorption (670 nm) relative to the green reflectance peak (550 nm) and infrared reflectance (700nm)

To prove the occurrence of pre-symptom stage (spectral) of ralstonia solanacearum infection in cucumber plant

To determine the possibility of inducing a measurable spectral change by using nutrient, light exposure and water stress during the pre-symptom stage

InoculatedInoculated

InoculatedInoculatedNon-inoculated

Non-inoculatedNon-inoculated

Non-inoculated

Normal Condition

Light StressWater Stress

Nutrient Stress

The occurrence of pre-symptom spectral stage of ralstonia solanacearum infection in cucumber plant has been proven, and last at least 10 days in this experimental conditions.

There is a possibility of inducing a measurable spectral change by reducing light exposure (-5 hours) during the spectral pre-symptom stage. MCARI and NRI vegetation indices respond to this induced EM-Spectral change.

Understanding!Modeling and Generalization! Implementation feasibility? . . .Monetising!

Questions?