Get your soil right; the rest will follow

What is soil health? Soil health is the ability of a soil to sustain, in the long term, its most important functions.

A healthy soil will be able to sustain crop and livestock productivity and maintain or enhance environmental benefits. It requires a good balance of physical, chemical and biological soil properties, many of which can be assessed or tested.

The first step to a healthy soil

Soil pH is a key component of soil health. However, it is an aspect of soil which has deteriorated to an alarming level despite the message of its importance being constantly repeated.

A large proportion of soils in Ireland are in poor health status from a soil pH perspective. If we had livestock in the same proportion on our farms suffering from ill-health we would not wait as long to treat them. It is imperative that we soil test regularly and correct soil pH quickly.

How do you test soil health?

Soil health tests are divided into three main types:

  1. Physical characteristics;
  2. Chemical nutrient status;
  3. Biological parameters.

Although some parameters are more conventional indicators of soil health, a more integrated approach will be needed to balance chemical fertiliser inputs more strategically to maximise efficiency and reduce losses into the future.

Physical tests

Soil physical tests can provide information on how well soils can function under varying weather conditions. Physical condition is an essential part of soil health.

Soil texture and the other characteristics of the soil types occurring on a farm should be known and documented.

Structural assessments, such as the Visual Evaluation of Soil Structure (VESS), can also be conducted. Such assessments can be used to help identify the presence of compaction.

Chemical tests

Soil chemical tests should be chosen based on the production system and its perceived problems. The basic parameters – pH, nutrient status (phosphorus (P) and potassium (K), calcium (Ca) and magnesium (Mg)) and soil organic matter – should be tested regularly.

More chemical tests can be selected based on the crops grown (e.g. soil trace element concentrations are useful in some situations).

Biological tests

Soil biological tests include counting earthworms, measuring soil respiration and assessments of the soil food web. These tests are relatively new. Soil respiration is a measure of the living microbial population within the soil.

When should soil health be tested?

In general, soil health changes slowly, although soil physical condition can be badly damaged in a single grazing, cultivation, or harvest event if conditions are poor.

How often soil tests should be conducted varies considerably and depends not only on the test but also on the value of the crop. Some tests can be done annually; others every three to five years.

Tests that measure gradual changes can be done every five years or more. To monitor long-term changes in soil health, tests should be repeated at the same point in the rotation.

Annual soil assessments

Digging soil pits, to look at soil structure and compaction as well as biological tests, such as earthworm counts, should, ideally, be done annually at the same time of year (usually spring and/or autumn).

Tests every 3 to 5 years

In general, tests for pH and major nutrients should be conducted at least every three to five years (potentially more often in light soils producing high value crops).

Measuring soil respiration over this time period can also be considered, provided that appropriate guidance on interpretation of results is available.

Tests 5 years +

Soil organic matter changes slowly and there is little point in conducting tests more often than once every five years (potentially only every 10 years unless significant amounts of organic matter have been applied annually).

VESS assessment of the long-term farmyard manure (left) and control (right) treatments. Image source: AHDB

Grassland Agro has a dedicated team of agronomy advisors that are trained in the VESS system, preparation of fertiliser programmes to balance the chemical requirements of the soil and can offer a soil biology test to assess biological activity.

If you want to receive a free soil health assessment, please click here

Also Read: Sustainability: Developing a bespoke fertiliser plan to suit your farm

In conjunction with on-farm support, Grassland Agro has a unique range of soil conditioning products to promote a healthy soil.

Physiolith Soil Conditioner

Physiolith from Grassland Agro is a unique product that is designed to condition the soil. It has two key ingredients that provide benefits.

It contains a marine calcium material called “Calcimer“ which acts as a source of Ca for both soil structural improvement and plant nutrition, along with “Physio+” root stimulant technology.

It also works as a soil surface pH stabiliser to maintain the soil pH at optimum levels and counteract the naturally acidification of soil that will occur due to rainfall, crop growth and fertiliser application. By maintaining and optimising the soil pH, the availability of nutrients in the soil are maximised.

The highly porous nature of Calcimer makes it more reactive than conventional liming materials, and the porous structure also provides micro-sites for beneficial soil bacteria to flourish.

The other key ingredient of Physiolith is a plant root stimulant called “Physio+” that is extracted from seaweed using a patented technology.

“Physio+” causes the plant to send out more roots and root hairs, helping the grass or crop to exploit a greater volume of the soil for water and nutrient uptake. It also gives the plant better anchorage in the soil, resulting in sod-pull during grazing.

Does Physiolith work?

Yes. On-farm trials in grazed pasture proved that Physiolith has beneficial effects on both grass yield and quality.

Yield benefits of 1.6 t/ha of extra grass dry matter were measured on paddocks that received two bags/ac of Physiolith compared with paddocks that received no Physiolith.

The paddocks that received Physiolith also had higher Ca and P contents in the grass, thus showing the potential of Physiolith to boost nutrient uptake from the soil due to the increased rooting.

Solelith K+

In addition to Physiolith, Grassland Agro is launching a new soil conditioner product this autumn.

“Solelith K+” contains Calcimer soil conditioner, Pheoflore soil microbe stimulant technology along with a high level of K and Ca. Sulphur (S) and Mg are also included to enhance the overall balance of secondary nutrients that are often omitted from conventional NPK products.

The product is designed for autumn application to provide K nutrition to the soil and increase soil biological activity and health for the following year.

S and Mg are also a fundamental part of the product to stimulate microbial activity to increase soil nitrogen mineralisation. Solelith K+ also contains the marine origin soil conditioner “Calcimer” which is combined with K in a CCF granule.

To read more of the potassium soil fertility focus article, just click here