Q1.
Observe the photographs (Fig. 2.9) and also note the types of erosion. How are farmers affected by erosion due to water and wind?
Answer
First, the two photographs.
| Photograph | What you can see | Type of erosion |
|---|---|---|
| Fig. 2.9 (a) | A bare slope cut into deep, branching channels with steep raw sides, and a thin stream at the bottom. There is a little grass surviving only at the very top, where the ground has not yet been cut into. | Water erosion — gully erosion by running water |
| Fig. 2.9 (b) | Dry pale grassland with a few trees, and the air thick with drifting brown dust so that the far trees are almost hidden. The ground is bare between the tufts of grass. | Wind erosion — fine soil being lifted and carried away |
How farmers are affected — water erosion:
- Rain water running downhill first strips the fertile topsoil, which is the only layer that holds the nutrients and organic matter crops need. Yields fall even though the field looks unchanged.
- If it continues, the sheet of running water concentrates into rills and then gullies, as in photograph (a). A gullied field cannot be ploughed at all; the land is lost outright and the plot is cut into unusable pieces.
- The eroded soil is dumped downstream, silting up canals, tanks and reservoirs and reducing the water available for irrigation.
- Along rivers and coasts, erosion washes away land, houses and roads — page 21 lists this as a direct loss of property.
How farmers are affected — wind erosion:
- Wind lifts the finest particles first — exactly the clay and humus that make soil fertile — and leaves behind coarse sand. The field slowly turns from soil into sand.
- Blowing sand buries young crops and sand-blasts standing plants, damaging leaves and stems.
- Seed and fertiliser broadcast on a loose dry field are simply blown away, so the farmer's investment is lost before the crop starts.
- Repeated wind erosion leads towards desertification, after which the land cannot be farmed at all.
Why both begin the same way — bare soil. Erosion needs loose particles and an agent to move them. A crop canopy or grass cover breaks the force of falling raindrops and slows the wind at ground level, and roots bind the particles together. Remove the cover — by deforestation, overgrazing, or leaving a field bare between crops — and both water and wind can start work at once. That is why every remedy in this chapter is about putting a cover or a barrier back.
Check it yourself: page 21 also names the answers Indian farmers worked out long ago — contouring (continuous contour trenches dug along the contour lines of a hillside to slow, hold and soak in rainwater), bunding (earthen embankments along the contour to cut run-off), terracing (level steps cut into a hillside) — and the Zabo system of Nagaland, where earthen bunds on hill slopes and check dams across small streams slow the water, trap sediment and recharge groundwater.