Yield Estimation

After flood vegetation cover analysis of Dera Ghazi Khan and Taunsa

Agriculture is the back bone of Pakistan. Even though 45% of the country’s total population belongs to this profession, people have to face many natural and manmade problems. Flooding caused massive damages across Pakistan in summer of 2022. An effort has been made by the NCBC-PAAL team to analyze the vegetation cover of D.G Khan and Taunsa districts after the floods. Though most of the flood water has dried up but still not all the land is good for cultivation.

Figure 1: Map of Dera Ghazi Khan and Taunsa (Admin Boundary Source: FAO)

Satellite imagery provides the large spatial and temporal scales necessary to address vegetation analysis in an appropriate way. Numerous remote sensing studies have been involved in the mapping and analysis of relative vegetation cover at various scales, utilizing indices based on optical spectral behavior of vegetation. The remote detection of vegetation allows verifying its occurrence in a given locality, accompanying its changes over time and quantifying its area and scope, by means of digital interpretation and image processing.

True Color/RGB Composite

Figure 2: Sentinel 2 RGB/True Color images of Dera Ghazi Khan and Taunsa Regions in Dec 2021 and Dec 2022

PAAL employed Change Detection method for the analysis of Satellite image based on Normalized Difference Vegetation Index (NDVI). Land Resources are easily interpreted by computing their Normalized Difference Vegetation Index for Land Cover classification.

Normalized Difference Vegetation Index

Figure 3: Sentinel 2 Normalized Difference Vegetation Index of Dera Ghazi Khan and Taunsa Regions in Dec 2021 and Dec 2022

Further PAAL used European Space Agency’s Land Cover Land Use (ESA World Cover 10m 2020) map to segregate crop land from all other land use types to highlight vegetation difference pattern.

European Space Agency (ESA) World Cover

PAAL team visited following sites and verified the information depicted in these images. Site Nari Shumali land is still covered by wet silt. While Site Bulani is partially revived.

Figure 4: ESA Land use classification of the region

NDVI Crop Land

Figure 5: NDVI calculation of area defined as crop land by ESA

Bulani

Conclusion:

Both regions are still not fully recovered from flood effects. Parts of the areas are still covered by silt making it impossible to plough the fields as tractors get stuck in the mud. Low/sparse vegetation increase is shown by the satellite images but it could be naturally grown weeds. Lack of dense vegetation is clear, indicating late sowing. Taunsa seems more affected as vegetation cover compared to last year is very low. In contrast, vegetation cover of D.G Khan appears to be better than previous year.