EFFECTS OF FLOODING ON AGRICULTURAL FARMLANDS IN AFRICA
Flooding in key agricultural production areas can lead to widespread damage to crops, fencing, and loss of livestock. Crop losses through rain damage, waterlogged soils, and delays in harvesting are further intensified by transport problems due to flooded roads and damaged infrastructure.
Floods are the most common natural calamity, and they occur when water overflows and submerges normally dry terrain. Floods in coastal locations are frequently produced by heavy rainfall, quick snowmelt, or a storm surge from a tropical cyclone or tsunami.
EFFECT OF FLOOD ON AGRICULTURAL FARMLANDS
- Oxygen Depletion.
The immediate cause of plant damage and death is oxygen deprivation, as water contains less oxygen than air. The oxygen depletion can be caused by any of the following:
- Plant respiration rates (oxygen consumption) are determined by temperature, warmer floodwaters simply faster depletion of dissolved oxygen and greater crop damage.
- Crop submersion length is an essential factor—the longer a crop is submerged, the longer it is exposed to low oxygen, and therefore greater damage occurs.
- Water movement is important because flowing water has more dissolved oxygen than motionless or slow water. Naturally, fast-moving water can knock plants over (“lodging”) or wash away the applied manure or fertilizers, resulting in crop damage.
- Crop development is critical. Young maize, sesame plants, and soybean plants are more vulnerable to flooding than older plants, although flooding of more mature crops during other important stages (e.g., blooming) can still be harmful.
- Disease & Loss of Soil Nutrients
Even after the floodwaters recede, crops might sustain damage and production losses. Flooding not only lowers plant defenses, but the soil and water conditions frequent during flooding promote the development of numerous plant diseases, resulting in increased disease issues in crops following floods.
Flooding also causes soil nitrogen loss due to increased denitrification under anaerobic soil conditions that remain throughout the flooding. Nitrogen is essential for crop growth, and most farmers apply some extra nitrogen to their crops, particularly corn.
- Competition & Erosion
Flooded crops may experience developmental delays and be unable to attain canopy closure, which is required for crops to outcompete weeds and produce high yields. Farmers may need to apply more weed control (chemical or mechanical), which inflates expenses, and late-spring management is frequently ineffective or causes crop damage. Furthermore, flooded farms can introduce new weed seeds, raising control expenses and reducing yields in subsequent years.
Finally, flooding shifts soil, which can cause more crop harm. Erosion sweeps away the fertile topsoil, raising input costs and lowering future harvests. Another key issue is soil deposition. Even fertile silt can suffocate an established crop with a few inches of deposition. Floodwaters can also dump sand and gravel on agriculture, forcing their removal or spreading out and mixing in. These deposits are likely to be less productive than the existing soil, implying higher input costs and lower yields in the future.
SOLUTIONS
- There are financial tools that can be employed to respond to and mitigate the impacts of floods and other extreme weather conditions in general, for example, weather-index-based micro-agricultural insurance can be used to cover when floods or other weather-based disasters struck.
- Deforestation should be avoided. Planting trees, shrubs, and hedges around farmlands can help protect crops from flooding and retain soil swept away by rushing water.
- Local knowledge and resources should be highly considered to ensure sustainability and cost-effectiveness.
