Contour plowing

The extent of the problem was such that the 1934 "Yearbook of Agriculture" noted that Approximately 35 million acres [142,000 km2] of formerly cultivated land have essentially been destroyed for crop production.

Importantly, the technique also significantly reduces soil erosion and fertilizer loss, making farming less energy and resource-intensive under most circumstances.

[8] Reducing fertilizer loss saves the farmer time and money and decreases the risk of harming regional freshwater systems.

Soil erosion caused by heavy rain can encourage the development of rills and gullies which carry excess nutrients into freshwater systems through the process of eutrophication[9] Contour plowing is also promoted in countries with rainfall patterns similar to those in the United States, such as western Canada and Australia.

On steeper slopes and areas with greater rainfall, a procedure known as strip cropping is used with contour farming to provide additional protection.

Farming sites are often classified into five levels: insensitive, mild, moderate, high, and extreme, depending on the region's soil sensitivity.

[12] Contour farming is applied in certain European countries such as Belgium, Italy, Greece, Romania, Slovenia, and Spain in areas with higher than 10% slope.