Question

In this soil conservation method, several grasses are left out in soil after the crop is harvested
A. Tillage
B. Crop rotation
C. Terrace farming
D. Contour farming

Answer 1

Soil conservation involves the methods that helps in preventing the degradation of soil and helps in formation and building up of organic matter.

Complete answer:
TILLAGE- it is the method of mechanical agitation or mechanical agricultural methods of various types such as digging, stirring, and overturning to improve the crop yield.
CROP ROTATION- it helps to increase the fertility of the soil. Crop rotation is the process of growing a series of different types of crops in the same area in sequenced seasons for one or two years.
TERRACE FARMING- this farming is a type of farming that consists of various steps called a terrace.
CONTOUR FARMING- in this type of farming is done and then several kinds of grass are left out in soil after the crop is harvested. Crops are placed perpendicular to slopes to follow the contours of a slope of a field in this field, which helps in breaking down the continuous flow of water and prevent soil erosion.
contour farming or Contour ploughing is the farming practice of ploughing or planting across a slope following its elevation contour lines. These contour lines create a water break from a continuous flow of water which reduces the formation of rills and gullies during times of heavy precipitation, allowing more time for the water to settle into the soil.in contour farming, the ruts made by the plough run perpendicular instead of parallel to the slopes, generally resulting in furrows that curve around the lands and are in level. This method is also known for preventing soil erosion. Tillage erosion is nothing else; it is just the soil movement and erosion by tilling a given plot of land. A similar practice is contour farming where stones are placed around the contours of slopes which are in perpendicular manners. Contour ploughing helps ultimately to reduce soil erosion a lot.

Hence, the correct answer is option (D).

Note: As contour term indicates that it is done several kinds of grass are left out in the soil even after harvesting and done in the region of the plane area so it is the best way to answer the questions easily.