Which one of the following is not a measure for soil conservation, in modern times?

Question

Accepted Answer

The correct option is 3:
Jhum cultivation, also known as shifting cultivation or slash-and-burn agriculture, is the correct answer because it is fundamentally a practice that leads to *soil degradation* rather than conservation. This method involves clearing a plot of forest land, burning the remaining vegetation to enrich the soil with a temporary layer of ash, and then farming the land for a short cycle until the meagre soil nutrients are exhausted. Following the decline in soil fertility and crop yields, the farmers abandon the plot to allow the forest to regenerate naturally and move to a fresh area. While historically a sustainable practice in sparsely populated areas with long fallow periods (up to 20 years), the modern context of increasing population pressure and shorter fallow cycles means the soil does not have enough time to recover its fertility or re-establish its protective vegetative cover. The clearing and subsequent abandonment accelerate severe soil erosion because the land is left bare and vulnerable to wind and heavy rainfall, making it the very antithesis of a soil conservation measure in modern times.

The incorrect option is 1:
Terracing is a highly effective and widely adopted soil conservation measure, particularly on steep slopes and hillsides. It involves the construction of a series of horizontal steps or platforms, resembling gigantic stairs, into the slope to create level or gently sloping farmlands. The primary benefit of terracing is its ability to significantly slow down the flow of surface runoff water, which is the main cause of gully and sheet erosion on sloped terrain. By intercepting the water's momentum and distributing it evenly, the terraces allow the water time to infiltrate the soil, which in turn reduces its erosive power and conserves moisture. This practice effectively prevents the loss of valuable fertile topsoil while also making intensive agriculture possible on otherwise unusable land, thereby proving its conservation value.

The incorrect option is 2:
Windbreaks are lines of trees or shrubs planted in one or more strategic rows across the field perimeter or at intervals within large fields. They are an excellent, natural method of soil conservation aimed primarily at mitigating the destructive forces of wind erosion, which is particularly prevalent in dry, flat, and open agricultural areas. The barrier works by significantly reducing the velocity of the wind across the ground surface, thereby eliminating the wind's capacity to lift and transport fine, fertile topsoil particles. In addition to preserving the soil, windbreaks also help conserve soil moisture by reducing the rate of evaporation and offer shelter for livestock and crops, increasing overall farm productivity and sustainability. They represent a fundamental, nature-based solution to long-term soil protection.

The incorrect option is 4:
Crop rotation is a fundamental and time-tested measure for maintaining and dramatically improving soil health and fertility over time. This practice involves systematically planning and planting different types of crops in the same area across a sequence of growing seasons, rather than planting the same crop repeatedly in a monoculture system. A key mechanism of crop rotation is the inclusion of leguminous crops (such as clover, peas, or beans), which harbor nitrogen-fixing bacteria in their roots, naturally enriching the soil with this essential macronutrient. Furthermore, rotating crops helps to disrupt the life cycles of specific pests and diseases, improves soil structure, and increases the overall organic matter content. These benefits directly contribute to the long-term conservation and sustainable productivity of the land, affirming its status as a vital modern conservation technique.