UPSC Prelims 2017 Question:

Which of the following statements can help in water conservation in agriculture?

1. Reduced or zero tillage of the land
2. Applying gypsum before irrigating the field
3. Allowing crop residue to remain in the field
   
   

Select the correct answer using the code given below:

Explanation: 

• Zero tillage is the process where the crop seed will be sown through drillers without prior land preparation and disturbing the soil where previous crop stubbles are present. Zero tillage not only reduces the cost of cultivation it also reduces soil erosion, crop duration and irrigation requirement and weed effect which is better than tillage. Zero Tillage (ZT) is also called No-Tillage or Nil Tillage. So, point 1 is correct.
  
  
• Gypsum helps soil better absorb water and reduces erosion. It also cuts down on phosphorus movement from soils to lakes and streams and improves the quality of various fruits and vegetables, among other benefits. Gypsum will change soil pH very slightly, yet it can promote better root development of crops, especially in acid soils, even without a big pH change. This is because gypsum counteracts the toxic effect of soluble aluminium on root development. Thus, gypsum is beneficial for addressing the issue of salinity. However, it is not helpful in water conservation in agriculture. So, point 2 is not correct.
  
  
• Leaving higher levels of crop residue and doing less tillage can increase the soil water balance by increasing the amount of water that infiltrates the soil from irrigation or precipitation, and decreasing the amount of water that runs off the soil surface. More residue and less tillage also reduce the rate of evaporation of water from the soil. Maintaining residue on the soil surface and doing less tillage can significantly reduce the amount of irrigation water needed to grow a crop. So, point 3 is correct.
  
  

Therefore, option (3) is the correct answer. 

Subject: Geography | Soils