February 17, 2012

Wasteland Reclamation - G1 mains - paper4

Some important practices leading to wasteland reclamation are discussed as under :

1. Afforestation and Reforestation. Afforestation means growing forests over culturable wastelands where there were no forests before due to lack of seeds, trees or other adverse

factors. Whereas, reforestation means replanting forests over areas where they were destroyed or degraded by overgrazing, shifting cultivation, excessive felling, forest fires, etc. Restoring forests will not only help in checking soil erosion, floods and water logging, but also increases the land productivity.

2.      Changing Agricultural Practices. Shifting (orjhoom) cultivation can be replaced by crop rotation, mixed cropping or developing plantation crops which would improve fertility and support a large population.

3.      Leaching. Salt affected lands can be recovered by leaching them with more water, especially in the areas where ground watertable is not high. In case of flood-prone and irrigated lands, salinity can be prevented by providing adequate drainage to such lands.

 4.     Managing Topography. When water runs downhill, it erodes soil. The faster it runs, the more soil it carries off the fields. Water runoff can be reduced by leaving grass strips in waterways and by :

(j) Contour ploughing that is, ploughing across the hill rather than up and down. The ridges created by cultivation make little dams that trap water and allow it to seep into the soil rather than running off. Contour ploughing is generally combined with strip farming.

(b) Strip farming, that is, the planting of different kinds of crops in alternating strips along the contours. When one crop is harvested, the other is still present to protect the soil and keep water from running straight downhill. (cj Tied ridges are often useful in areas where rainfall is very heavy. This method involves a series of ridges running at right angles to each other, so that water runoff is blocked in all directions and is encouraged to soak into the soil. (d) Terracing involves shaping the land to create level shelves of earth to hold water and soil. The edges of the terrace are planted with soil anchoring plant species. This is an expensive procedure, requiring either much hand labour or expensive machinery, but makes it possible to farm very steep hillsides.

5.     Drainage. This is required for water logged soil reclamation where excess water is removed by artificial drainage. It can be achieved in following manner :

(i) Surface drainage. This is used in areas where water stands on the fields after heavy

rains by providing ditches to run-off the excess water. («) Sub-surface drainage. Horizontal sub-surface drainage is provided in the form of perforated carrugated PVC pipes or open jointed pipes with an envelope of gravel 2-3 m below the land surface. Chances of evaporation of water leading to accumulation of salt almost become nil in this method.

6.     Mulching. Shifting sand can be controlled by mulching (use of artificial protective covering). Some plants such as potato tops, cotton stalks, maize stalks, tobacco stalks, etc., are used as a mulch. A mulch is a protective layer formed by the stubble i.e., the basal parts of herbaceous plants, especially cereals, attached to the soil after harvest. Mulches not only act as wind barriers, but also reduce evaporation and increase soil moisture by addition of organic matter. Mulching is effective against water erosion as well.

7.     Ecological Succession. Ecological succession is a natural process of establishment or re- establishment of an ecosystem. This approach is particularly useful in mining and industrial wastelands, where the agriculturally oriented methods fail. Instead of planting


No comments: