Soil Health and Conservation

Soil is made up of air, water, minerals, and plant and animal material (both living and dead). Soils rely on complex interactions between all of these components in order to function properly. Healthy soils have a porous structure, which allows air and water to move freely. Organisms such as bacteria, protozoa, fungi, and earthworms are all part of the biology of a healthy soil. Healthy soils are more resilient against drought and erosion, which is vital to crop production. Healthy soils are more resilient against drought and erosion, which is vital to crop production.  Listed below are recommendations for improving soil health, benefits of conservation tillage and cover crops, and information on the Conservation Cropping Systems Initiative created in 2009.

How to improve soil health:

  • Minimize disturbance
    A healthy soil structure is made up of stable aggregates, consisting of small holes which allow water and air to move through. When soil is tilled, this structure is destroyed. Without a porous structure, rainfall will be more likely to run off the surface of the soil instead of infiltrating down.
  • Cover the soil
    Keep the soil covered with crop residue year round. Bare soils are more likely to erode. Crop residues also help increase the amount of organic matter in the soil by providing food for organisms, like earthworms, which break down the residue into simpler forms where it can be utilized by plants.
  • Plant cover crops
    Cover crops are planted so that there is something growing in the soil during the times when a crop is not in the field. Like the use of crop residue, cover crops provide more organic matter to the soil and decrease erosion. Increased organic matter improves the aggregate stability and the water-holding capacity of a soil. In addition to organic matter, cover crops can be used to manage soil nutrients. By having continuous living roots in a soil, then nutrients are constantly being utilized by plants- instead of leaching out. Cover crops are managed to die and then release these nutrients at a time when the crop is growing needs them the most.
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Cover crops coming up among crop reside.
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Soil aggregate underwater, as part of a demonstration. Notice the bubbles as water moves through air spaces within soil pores

For more information on Soil Health:

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Benefits of No-Till/Low Till

There is a range of tillage practices used in modern farming. The most extreme tillage is done using a moldboard plow, which turns over the upper layer of soil, burying crop residue. The opposite end of the spectrum is no-till, where soil is not disturbed and residue is left on the soil’s surface. There are a variety of practices that lie somewhere in between, including conservation tillage and strip-till. There must be 30% residue left on the soil surface after planting to be considered conservation tillage.

No-Till Benefits to Soil Health

Soil health relies on the structure of the soil remaining intact. This structure consists of stable aggregates containing micropores, which allow air and water to move through the soil. Better aggregate stability means a more resilient soil. This soil structure is a result of complex interactions between microorganisms like bacteria, protozoa, and fungi; and earthworms. These pores allow water to infiltrate into the soil. Crop residues left on the surface decompose and add organic matter to the soil. Increased organic matter allows the soil to have a greater water holding capacity. These residues also slow the movement of surface water. Soils in a no-till system are less likely to erode and are more able to withstand both drought and heavy rain. All of these soil health benefits rely on the lack of tillage. Every time the soil is tilled, this complex system is damaged and essentially has to re-establish itself.

No-Till and Erosion

A field is most vulnerable to erosion during the winter, when crops are not in the field. Disturbed soil is more likely to erode, either by wind or water. Soils in a no-till system are more stable, and less likely to erode. No till fields have a high percentage of crop residue. This residue slows the movement of surface water along the soil’s surface, decreasing the erosive power. Since no till soils have a healthier structure, there is greater infiltration and less surface runoff. Root systems from the previous crop also hold soil together. It is crucial to retain valuable topsoil in the field, since healthier soils produce healthier crops.

Economic Benefits of No-Till

It is financially beneficial to reduce the amount of time equipment is running in the field. Time and money can be saved in terms of labor, fuel, and equipment wear and tear by eliminating tillage. Although there is an initial financial investment in terms of equipment, conversion to no- till saves money in the long run. No-till is extremely beneficial in terms of soil health. Healthier soils are more resilient, allowing crops to endure less-than-ideal growing conditions better than their counterparts on tilled fields. These healthier soils are also less prone to erosion. If there is less erosion occurring in a field, then there may also be less of a need for engineered practices like grassed waterways. These practices cost money and take land out of production. The erosion of fertile soils means that over time the soil in a field will be less valuable in terms of crop production.

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Crop residues are left in the field in a no- till system. This residue reduces erosion and improves overall soil health. Tillage disturbs the soil, destroying soil aggregates. When micropores and worm tunnels collapse water infiltration is reduced, resulting in greater surface runoff and ponding. Without crop residues holding the soil in place and slowing the flow of surface water erosion can occur. Soil conditions like platy structure, compaction, and decreased organic matter are all a result of tillage.

For more information on No-Till/ Low Till:

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Cover Crops

Cover crops are plants seeded into an agricultural field in addition to the cash crop. Cover crops are planted so that there is something growing in the field when cash crops are not.

Benefits of cover crops:

  • Reduce erosion – The use of cover crops has several benefits, one being that with plants being in the field year-round, the soil is never bare. Soil that is exposed is more prone to erosion than soil that is stabilized by plant roots.
  • Store nutrients – By keeping living roots in the soil year-round, nutrients are used by the plants instead of being leached out. Managing cover crops allows a producer to terminate cover crops at the proper time so that when cash crops are growing and in need of nutrients, like nitrogen, the cover crops will be decomposing and releasing nutrients and organic matter into the soil.
  • Improved infiltration – Pore spaces created by cover crop roots improve infiltration.
  • Weed suppression – Since the soil surface is never left bare, it is harder for weeds to become established.
  • Supplemental forage – Livestock can graze on cover crops over the winter.
  • Soil organic matter – Increasing the amount of organic matter improves aggregate stability, improving soil tilth and workability. A soil with a higher level of soil organic matter has higher water holding capacity, which decreases run-off and makes the soil more drought-resistant.
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Residue from last year’s corn crop mulches the soil around a soybean plant. Cereal rye covers the soil after the harvest. The roots of cover crops, like this oilseed radish, help to break up compacted soils.

For more information on Cover Crops:

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Conservation Cropping Systems Initiative

CCSINThe Conservation Cropping Systems Initiative, or CCSI, was created in 2009 to promote soil health across Indiana. The Indiana Association of Soil and Water Conservation Districts administers the Initiative and it is funded through various grants. CCSI advocates the use of practices like no-till and cover crops as part of a comprehensive farming system, with soil health being the focus.

CCSI hosts a variety of workshops and field days providing the latest soil health information to producers and agriculture professionals. CCSI partners with the On Farm Network, a program where farmers conduct research on their own farms to determine the pros and cons of various management practices. CCSI also established a mentoring program where farmers who are interested in incorporating new management practices can connect with people who have already had success with those practices on their own operations. CCSI has four regional hubs, which serve as centralized locations for training opportunities.  Trainings cover a variety of topics including examining soil pits, managing cover crops, precision agriculture, soil fertility, nutrient management and crop rotation.

oilseed-radish-oats Cereal-rye

The use of no-till and cover crops are part of a comprehensive farming system, based on improving soil health. Above left – Oilseed radish and oats cover a field after soybeans. Above right – Cereal rye is used here following corn.

For more information on Conservation Cropping Systems:

 

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