Soils test #2

Indicator- chemical

pH

Extractable NPK

Electrical conductivity

Relationship to soil health-Chemical

Biological and chemical activity thresholds

Plant and microbial activity thresholds

Plant available nutrients and potential for N and P loss

Biological

Soil respiration(soil breathes)

Mycorrhizae (white tissue) strands spread out into soil. Inside those cells is N C and K

Microbial biomass C (organic matter) and N

Potentially mineralizable N

Biological- relationship to soil health

Microbial activity measure

Microbial catalytic (conversion) potential and repository for C and N

(Beets left in the field, microbes will go nuts and consume the sugar. When microbe numbers go up, organic matter and the C: N ratio so both C and N will be decreased, making it unavailable for plants.) Can be mitigated by planting legume beans and N fert

Soil productivity and N supplying potential

Soil organic matter (SOM)

Cold areas will have high OM but low microbial activity (histisols). Swamps are another place where microbes will be low, but OM will be high. Soils can shrink 10-15 feet in Florida when we were draining swamps to add cities.

Soil fertility- measure high fertile soil, high aggragate stability

Structure

Stability

Nutrient retention

Soil erosion

Soil quality is not an end in itself:

The ultimate purpose of researching and assessing soil quality is not to achieve high aggregate stability, biological activity, or some other soil property.

Row crops are important for root penetration into the soil.

The purpose is to protect and improve long-term productivity, water quality, and habitats of all organisms, including people.

Soil quality must be identified by how it performs its functions.

Older people and babies get sick when nitrate is in the water.

Managing for soil quality

Each combination of soil type and land use calls for a different set of practices to enhance soil quality. Yet, several principles apply in most situations.

1. Add organic matter (spreading manure, green manures) OM may come from crop residues at the surface, roots of cover crops, animal manure, green manure, compost, no till.)

2. Avoid excessive tillage- tillage has positive effects, but it also triggers excessive OM degradation, disrupts soil structure, and can cause compaction. OM disappears when tillage is all the time.

3. Carefully manage fertilizer and pesticide use- fert can increase plant growth and the amount of OM returned to the soil. They can harm non-target organisms and pollute water and air if they are mismanaged. Related to soil quality and people. Manure and OM can also become pollutants when misapplied or overapplied.

4. Increase ground cover- bare soil is susceptible to wind and water erosion, and to drying and crusting. Ground cover protects soil, provides habitats for larger soil organisms, such as insects and earthworms, and can improve water availability.

5. Plant diversity- each crop contributes a unique root structure and type of residue to the soil. “One plant does one thing, another does another thing”. Can help control pest populations, can reduce weeds and disease pressures

How to increase plant diversity

Diversity across the landscape and over time can be increased by using buffer strips, small fields, contour strip cropping, crop rotation, and by varying tillage practices.

Table 7.1 I have a voice memo of:

Texture can help regulate water movement because of clays.

silvopasture

trees in the pasture