2019 soil water management presentationsource: the nature and properties of soil , 15e, ray r. weil...

SOIL AND WATER MANAGEMENT

Soil Functions

Nutrient Cycling

Carbon Cycling

Soil

WaterCycling

Plant Growth

Chemical Fate &

Transport

BiodiversityProtection

CONSEQUENCES OF MISMANAGEMENT

CRITICAL SOIL PROPERTIES AND

FUNCTIONS

Gas

Liquids

Solids

Pores

Porosity – Proportion of Pores

Volume of Pores

Total Soil Volume

= Porosity

Soil texture and particle size

Infiltration

■ How quickly water enters the soil

■ Impacted by:

- Soil Texture

- Pore size

Macropores

Alaou and Goetz, Geoderma 2008Sophocleuos et al., Kansas State Geological survey

Soil structure and macroporesimpact infiltration

Slope and Infiltration

Rain

Infiltration

RainInfiltration

Low Slope Field High Slope Field

Factors Influencing Infiltration■ Soil Texture

Sandy ClayeyHigh infiltration Low Infiltration

■ Porosity (greater porosity = more infiltration)

– Porosity is influenced by compaction

■ Slope (Higher Slope = less infiltration)

Importance of Porosity

Porosity controls:• Maximum water

content of soils• Root Aeration• Water infiltration

Compaction: • Decreases Porosity• Increases Density

Compaction degrades pore networks

Source: The Nature and Properties of Soil, 15e, Ray R. Weil and Nyle C. Brady

Source: The Nature and Properties of Soil, 15e, Ray R. Weil and Nyle C. Brady

Source: The Nature and Properties of Soil, 15e, Ray R. Weil and Nyle C. Brady

Source: The Nature and Properties of Soil, 15e, Ray R. Weil and Nyle C. Brady

• Tillage can influence Compaction susceptibility

• Effects are greatest in young soils (e.g. soils in the Midwest)

Young Prairie Soil (Nebraska)

Very Old Forest Soil (Kentucky)

Factors influencing compaction■ Moist soil is weaker and more susceptible to compaction

(avoid traffic on wet soils)

■ High OM soils are less susceptible

■ High tillage increases compaction susceptibility

■ Heavy vehicle traffic increases compaction

– High volume tires (and tracks) keep compaction shallow

WATER QUALITY

Ag. Chemical

Volatilization /off-gassing

Deposition

Leaching

Flow in deep ground water

Surface Water

Groundwater

Importance of each mechanism depends on:• Chemical Type• Application Timing• Application method• Landscape (soil, slope, infiltration, conservation

practice, etc.)

Right Source

Right Rate

Right Time

Right Place

4 R’s of Nutrient Management

Right Rate

Manure/fertilizer application timing (Right Time)

SOIL EROSION

Mechanism of soil erosion

Erosion vs. Sedimentation

Erosion = movement of soil (via wind or water)

Sedimentation = impairment of water bodies by excess sediment additions

CONSERVATION PRACTICES

Riparian buffers and filter strips

Contours and grass waterways

Contour strips and buffers

Grass waterways

Cover Crops

Cover crops

Conventional vs. reduced/conservation tillage

Conservation Tillage = more crop residue