Farming practices that support soil health

Soil is a living, dynamic habitat for a great diversity of animals and plants.

It supports the global carbon and nitrogen cycles. Healthy soils sequester carbon, helping to mitigate climate change.

According to a report, 'Farming with Soil Life', farming practices that support soil health often need to be customised or adapted to local conditions.

However, some overarching strategies are used in nearly all climate zones, soil conditions, and crop systems.



Protect the soil

Some of the strategies that support soil health focus on a few key actions, such as minimising the potential for erosion through conservation systems that protect crop fields from wind and water runoff.

Other actions are to cover the soil as much as possible year-round or maintain continuous living root systems in the soil, reduce mechanical cultivation and compaction, and increase organic matter with natural inputs while reducing or eliminating synthetic fertiliser inputs.

Focus can also be placed on maximising crop diversity, integrating crops and livestock, and increasing soil biodiversity by reducing or eliminating pesticides, including soil fumigants.



Erosion-control buffers

The report says soil loss due to wind and water erosion is a natural, ongoing process that occurs on most soils in both natural and agricultural settings.

"While this loss is typically a slow process that may be largely unnoticed in natural settings, it is often accelerated by cultivation and grazing, requiring active work to counteract erosion and keep soil on the farm."

To reduce soil loss on farms, various conservation systems have been developed, such as terracing, contour buffer strips and windbreaks.



No-till cropping

The report states that no-till and reduced-tillage cropping systems provide good protection against soil erosion, reduce compaction, reduce disruption to fungal hyphae, and improve habitat for wildlife and beneficial insects.

Additionally, no-till cropping can reduce some greenhouse gas emissions.

"However, soil organic carbon (SOC) is not permanently sequestered by no-till cropping. Because no-till cropping primarily builds soil carbon in aggregates close to the soil surface, a single tillage event can lead to a large flush of microbial activity and loss of that soil organic carbon."

According to the report, to maintain any reduction in greenhouse gas emissions, no-till systems need to be continuously undisturbed in order to protect the soil organic carbon that is physically stabilised in soil aggregates.



Cover cropping

The report says that cover crops provide temporary or permanent vegetative cover to control erosion, reduce nutrient runoff and leaching, suppress weed growth, improve soil fertility, and increase biological diversity.

Farmers can customise particular cover crop mixes and management practices to meet their specific goals.



Crop rotations

Although most research examining the benefits of crop rotations focuses on soil fertility, research also confirms that increasing crop diversity through multispecies rotations produces a corresponding increase in soil species richness.

"Rotating annual crops with perennial forage crops, which may contain multiple species or a single species, benefits soil health by keeping the ground covered for many years, eliminating tillage and maintaining a living plant for most of the year during that portion of the rotation."



Organic soil inputs

According to the report, when focusing on soil health, nutrient management emphasises the role of natural inputs over synthetic ones.

Common natural inputs include compost, animal manure and bedding, bone meal and blood meal, seaweed and algae, and green manure crops, especially legumes.

Rotating livestock in fallowed fields provides an additional approach for manure-based fertilisation. Adaptive nutrient management is important during a transition to a soil health management system and depends on cropping systems and the availability of natural inputs.



Ley farming

Furthermore, the report states that ley farming, in which annual crop fields are not tilled but rather are sown with a perennial cover of a grass or legume for months or years, was historically a common method of rebuilding soil health.

Some farmers used fields in ley farming for hay production or livestock grazing.