Crop Health Explorer

Mpumalanga Province

Explore patterns of crop growth using NDVI across agricultural seasons. Toggle between phases using the map layers, click on fields (or enter GPS coordinates) to generate 3-year NDVI time-series plots, and identify irrigation or nutrient stress patterns over time.

The Science of Remote Sensing

🎛️ Interactive NDVI Simulator

Adjust the slider to simulate crop health. Healthy spongy mesophyll cells inside the leaf strongly scatter (reflect) Near-Infrared (NIR) light, while the chlorophyll pigment absorbs Red light for photosynthesis. As a plant becomes stressed, its cellular structure degrades, causing NIR reflectance to plummet and Red reflectance to increase.

NIR Reflectance: 50.0%
Red Reflectance: 8.0%
NDVI = (50.0 - 8.0) / (50.0 + 8.0)
NDVI Score: 0.72

🛰️ Sentinel-2 Satellite

The Sentinel-2 mission by the European Space Agency consists of twin satellites providing high-resolution (10m) optical imagery globally. With a revisit time of just 5 days, it is the perfect tool for monitoring rapid agricultural changes over a growing season.

🌱 Crop Maturation (Phenology)

A typical crop cycle shows a distinct NDVI curve: Planting starts low (bare soil), Peak Vegetative/Flowering reaches the highest NDVI (lush green canopy), and Harvest/Senescence drops back down as the plant dries out and turns brown.

⚠️ Recognizing Crop Stress & Rotation

When a crop is deprived of water (drought/irrigation failure), lacks nutrients, or is attacked by pests, its cellular structure breaks down. This causes NIR reflection to plummet, drastically lowering the NDVI value.

  • Center Pivots: Look for "Pac-Man" shapes or rings inside circular fields—these indicate clogged sprinkler nozzles.
  • Dryland: Compare a field's peak NDVI to neighboring fields; stunted growth indicates poor soil or localized drought.
  • Crop Rotation: By looking at 3 years of data, you can spot crop rotation. A farm might plant Maize one year (peaking in January) and Winter Wheat the next (peaking in August). You will see the peaks shift dramatically on the timeline!