What is soil health?

What is the quickest way to improve soil health?

There are four keys to improving soil health:

• Less Disturbance
• Increase Cover
• Increase Diversity
• Have living roots all year

Why is tillage not the answer to addressing soil compaction?

Tillage breaks down soil aggregates resulting in destruction of soil structure. Soil structure provides channels and macro pores that allow water, air, and root movement. When structure is destroyed, compacted zones form restricting air, water, and root penetration. Tillage can be used to remove the zone of compaction temporarily. The long-term solution is to plant cover crops to increase organic matter, soil organisms, and aggregate stability, thus improving soil structure. Fibrous roots of cover crops such as cereal rye will reduce soil bulk density. Brassicas, with deep tap roots, will loosen the soil. As soil organisms increase, they will continue to aggregate the soil and form bio-pores and channels. As soil health improves, the soil is more resilient to soil compaction.

Why is keeping the soil covered and increasing soil cover essential for soil health?

Increasing soil cover leads to increase of active soil organic matter as soil microbes begin to break down organic material. Also, maintaining good cover on soil surface protects break down of soil aggregates that leads to soil erosion.

Why is increasing diversity so essential for improving soil health?

Diverse plants above the soil equals diverse soil life, both macro and micro organisms. Healthy soil life reduces pressures of soil disease, weed, and insect pressures. Good diversity also has an rotation effect that leads to increase in crop yields.

Why is having living roots all year essential to soil health?

Roots by themselves provide diversity. Fibrous roots reduce bulk density, tap roots loosen compaction, deep roots uptake or scavenge N, P, and other nutrients. Also the rhizosphere (area around roots) are areas highest of concentration for soil life. Roots release exhudates that soil life feeds off of these proteins and sugars.

What cover crop is best?

It depends on a lot of factors: what crop are you following, what crop are you planning to plant after the cover crop, do you need more soil cover, a nitrogen fixer, a nitrogen scavenger, to mitigate soil compaction, lots to think about (plan).

What cover crop is best to reduce compacted or tight soil?

Radishes have gotten lots of press which I first doubted but they are a good component of a mix. They have a big root that can go down a foot or more, a smaller tap root that continues on 3’ or deeper depending on the soil.

What cover crop is best as a nitrogen fixer?

It depends on soil type and primary crops you produce. Hairy vetch is an excellent legume adapted to about every soil type and drainage group but most wheat producers don’t want it because it can be invasive in small grain crops. Crimson clover is the most common cover crop planted. Other choices include: Austrian winter peas, red clover, sweet clover, tropical sun hemp, cowpeas, soybeans and other legumes.

Why plant a mix of different species?

Plant diversity is one of the pillars of soil health. Diversity provides different rooting structures, and different root exudates (sugars) that feed a diversity of soil biology. Plant diversity can increase biomass produced and help insure against cover crop failure. The mix should not contain too high of a rate of early growth species like brassicas or they can smother the rest of the species.

What about planting warm season and cool season cover crops together?

There are benefits to planting cool and warm season cover crop species together but don’t plant too high of a rate of a warm season going into the cool season or too high a rate of a cool season species going into the warm season. Typically 20% or less is enough of the cover crop planted at the end of its normal growing season. Planting date is important too, with a cool season planting you don’t want more than 60 days growth of the warm season prior to the first frost.

Why are earthworms important?

Earthworms are a very important ally in improving soil health. They improve aeration and water infiltration by developing macropores, channels for water and air movement and they improve aggregate stability. Earthworm castings are five to six times more fertile than surrounding soil.

 

 

 

How do I increase earthworm activity in my soil?

Living roots and biomass (crop residue) on the soil surface feeds soil life. Interestingly the earthworm is a farmer, they pull residue underground to feed bacteria which are then eaten by protozoa. The earthworm then consumes the bacteria. Reducing tillage and disturbance preserves their habitat and their benefits.

What cover crop should I plant if I have excessive crop residue on the surface?

If you want soil life to consume and mineralize some of that biomass you need a low Carbon to Nitrogen ratio. Plants like brassicas and legumes have a lower C:N ratio. Greater than 25:1 increases residue on the surface whereas C:N ratio’s below 25:1 mineralize fast and decrease surface residue.

The following documents are provided in Adobe PDF format, click here for a free reader.

How do I know the Carbon Nitrogen ratio of my cover crop mix?

The link below will estimate the C:N ratio for a selected mix based on your location, stage of maturity, rainfall and seed mix.

https://greencoverseed.com/smartmix-calculator/

Do I need to inoculate legumes?

Rhizobium inoculant types for leguminous species to obtain nitrogen fixation
Table 1.10-3. Rhizobium inoculant types for leguminous species to obtain nitrogen fixation.
Rhizobium group and species	Legumes treated
Source: Adapted from “What Treats What?” (Ames, Iowa: Becker Underwood, 2008).
Alfalfa/medic group (Sinorhizobium meliloti)	Alfalfa, Medic, Yellow or white sweet clover
Cowpea, peanut, and lespedeza group (Bradyrhizobium sp. (Vigna))	Common lespedeza, Cowpea, Peanut, Velvet bean
Crownvetch group (Rhizobium sp.)	Crownvetch
Dry and snap bean group (Rhizobium leguminosarum biovar phaseoli)	Kidney beans, Snap beans, String beans, Wax beans
Lupin group (Bradyrhizobium sp. (Lupinus))	Lupin
Soybean group (Bradyrhizobium japonicum)	Soybeans
Trefoil group (Rhizobium loti)	Birdsfoot trefoil
True clover group (Rhizobium leguminosarum biovar trifoli)	Crimson clover, Red clover, White clover, Other true clovers
Vetch/pea group (Rhizobium leguminosarum biovar viceae)	Austrian winter pea, Common vetch, Faba bean, Field pea, Flat pea, Garden pea, Hairy vetch, Lentil, Sweet pea
Source: Adapted from “What Treats What?” (Ames, Iowa: Becker Underwood, 2008).

How do I get a cover crop established after soybeans?

Cereal Rye is the most winter hardy species that can be planted as late as November 20 but most other cool season species need to be planted by October 15. Planting an early maturing soybean will improve the window for planting the cover crop. A group 3 soybean is recommended. Aerial seeding is another option. The ideal time to aerial seed is at first leaf drop of the soybeans when there is moisture in the soil and follow up rain is forecast.

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