Soil Erosion Reduced by a Factor of Almost Thirty, Ensuring Fruit Cultivation for the Next 100 Years

Key Achievements

Scientific photographs taken from Unmanned Aerial Vehicles, like the QuestUAV Agri-Pro system, and processed with Pix4D are a powerful tool to fight soil erosion. Our case study shows that image-based farm management can significantly reduce the soil loss on tropical fruit plantations, such as pineapple. In our study a reduction from intolerable 200 t/ha/yr was reduced to tolerable soil loss levels of <15 t/ha/yr; a factor of 27 times improvement. The management at Dole Philippines were both surprised and delighted by the effectiveness of the UAV derived plans.

Soil erosion is considered to pose a major threat for pineapple production and environmental preservation in the Philippines. Soil loss rates vary with rainfall, elevation, slope gradient and soil characteristics and can reach up to 250 t/ha/yr. Based on experimental results, those losses can decrease potential yields as much as 30% in one crop cycle. Fighting soil erosion is therefore a major objective to move to a sustainable cultivation of pineapple in the Philippines.

Unmanned Aerial Vehicles (UAVs) combined with know-how in farm management provide new opportunities to significantly reduce soil erosion. Digital Elevation Models (DEMs) gained from UAVs are the basis for designing relief-adapted field layouts (planting rows, drainage channels) and an effective placement of soil conservation structures.

Project Scope

Our study was carried out on the world’s largest pineapple plantation, managed by Dole Philippines Inc. and located at the footslopes of a volcanic cone on the island Mindanao. The area has a total size of 220 sqkm and a strong relief.

Since March 2014 Dole Philippines has been flying their fields on a daily basis with two QuestUAV Agri-Pros. The Quest UAV “Agri-Pro” carries a Twin NDVI sensor providing Dole Philippines with RGB and NIR information at a spatial resolution of 5 cm. The images are the basis for designing and implementing new relief-adapted field layouts and soil conservation structures. The whole implementation workflow was developed by Dole Philippines in close cooperation with the German company ORCA Geo Services (GIS and agricultural consulting) and QuestUAV.

Dole Philippines, as a leading agricultural company in the Philippines, has an excellent environmental protection policy for its agricultural production. Soil erosion is continuously measured and analysed over time, allowing comparisons between soil loss rates of old and new, relief-adapted field layouts.

Results and Conclusions

The graphic below shows how the old field layout has been adapted to the relief on the basis of a Natural Color Image and a Digital Elevation Model (DEM). The total area of the field is 85 hectares. The images were acquired with the QuestUAV Agri-Pro System. The image processing was performed with Pix4Dmapper Pro. QGIS was used to design the new field layout.

The old field layout shows that planting contours do not follow the contour of the terrain. In some parts of the field, planting blocks are oriented perpendicular to the contour and rain events have a massive erosive effect. Water masses will flow directly downslope transporting huge amounts of soil material. A soil loss rate of 200 t/ha/yr was measured for the steep-slope parts of the field.

Contour lines were calculated on the basis of the DEM. Contour lines indicate the ideal shape and orientation of planting rows. Ideal planting contours would follow curves rather than straight blocks. As curved planting rows are not practical for large field machinery, a compromise was required. The field has been divided into two regions with different block orientations.

After the layout design was implemented in the field, new UAV images were taken. The updated image product shows how the block orientation has been changed according to the design. A direct downslope flow of water is hindered by the pineapple plants. By only changing the block orientation, the soil loss rate was reduced significantly from 200 t/ha/yr to 13 t/ha/yr.

Dole Philippines is planning to install additional soil conservation structures to reduce the soil rate further to <5 t/ha/yr. Their conservation programme includes, amongst others, mulching, the protection of receptor and tributary channels, the construction of sediment catching ponds and a special conservation strategy for gullies.

http://www.questuav.com/news/photogrammetry-dramatically-increases-lifetime-of-worlds-largest-pineapple-plantation