Page 70 - Nutrient Management Planning Guide

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Chapter 3.1

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The grade of slopes adjacent to water bodies influences the required setback distance for certain manure application conditions under AOPA (Chapter 4.4).

Adapted from Soil Conservation Service, 1991

Figure 3.1.7 Relative Rate of Water Infiltration of Various Soil Structures

Practices that enhance or promote good soil structure include:

applying manure to the land • including perennial forage crops in rotation • returning crop residues to the land • direct seeding or carefully managing tillage •

operations applying calcium-based amendments • deep ripping of soils with subsoil hardpans • avoiding field traffic during wet soil conditions •

Slope

Sloped land presents a natural risk of runoff and erosion. Erosion from slopes adjacent to water bodies can increase nutrient transport to surface water. The grade and length of slope influences the potential of such risks.

Slope Grade

Slope grade is a ratio of the change in elevation over a given horizontal distance (Figure 3.1.8). In many fields slopes are not uniform, but instead have dips and bumps along their length. For practical purposes, nutrient management planning is concerned with the average grade of a slope.

Figure 3.1.8 Measurement of Slope

Soil sampling strategies (discussed in Chapter 3.3) are also influenced by the general topography and presence of slopes in a field.

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