Correct Answer: (c) 1, 3 and 4
Solution:The appropriate method for soil conservation is done by crop rotation, terracing and windbreaks. Crop Rotation:
Adopting sustainable agricultural practices is the most important measure to conserve soil. In many parts of India, a particular crop is sown in the same field year after year. This practice leads to exhaustion of certain nutrients in the soil making it infertile. Crop rotation is a practice in which a different crop is cultivated on a piece of land each year. This helps to conserve soil fertility as different crops require different nutrients from the soil. Crop rotation will provide enough time to restore lost nutrients. For example, potatoes require much potash, but wheat requires nitrate. Thus, it is best to alternate crops in the field. Legumes such as peas, beans, and many other plants, add nitrates to the soil by converting free nitrogen in the air into nitrogenous nodules on their roots. Thus, if they are included in the crop rotation nitrogenous fertilisers can be dispensed with.
Terracing:
In terracing, a number of terraces are cut along the hill slope. These are made on the steep slopes so that flat surfaces are available to grow crops. They can reduce surface run-off and soil erosion.
Shelterbelts or Windbreaks:
In the coastal and dry regions, rows of trees are planted to check the wind movement to protect soil cover.
Sand fences:
Sand fences are barriers made of small, evenly spaced wooden slats or fabric. They are erected to reduce wind velocity and to trap blowing sand. Sand fences can be used as perimeter controls around open construction sites to keep sediments from being blown offsite by the wind.
