In the Technical Specification for Land Use Survey issued by China Agricultural Teachers Committee 1984, the slope of cultivated land is divided into five grades, namely ≤ 2, 2 ~ 6, 6 ~15,15 ~ 25, and greater than 25. Different grades of ground slope have different effects on cultivated land utilization.

≤ 2 generally no soil erosion phenomenon; Mild soil erosion can occur from 2 to 6 o'clock, so attention should be paid to soil and water conservation; Moderate soil erosion can occur in 6 ~ 15, and measures such as building terraces and contour planting should be taken to strengthen soil and water conservation.

15 to 25 The soil erosion is serious, and comprehensive measures such as engineering and biology must be taken to prevent soil erosion. & gt25 is the limit slope of land reclamation stipulated in the Soil and Water Conservation Law, that is, it is not allowed to cultivate crops. Those that have been reclaimed as cultivated land should gradually return farmland to forests and grasslands.

Extended data

Representation method: There are four methods to express slope: percentage method, degree method, density method and fraction method, among which percentage method and degree method are commonly used.

1, percentage method

The most commonly used method of expressing slope, that is, the height difference between two points and the percentage of their horizontal distance, is calculated as follows:

Slope = (elevation difference/horizontal distance) x 100%

When expressed as a percentage,

2. Degree method

The gradient is expressed in degrees and calculated by inverse trigonometric function, and its formula is as follows:

Tanα (slope) = height difference/horizontal distance

Baidu Encyclopedia-Grading of Farmland Slope