Welcome to the third instalment of our new 12 part Know your Soils series sharing practical tips for monitoring the soil health on your land. Keep an eye out for our bitesize videos and fact sheets on simple tests you can do yourself on farm.
“If you can’t measure it, you can’t improve it.”
How much topsoil and nutrients do you lose with rain water run-off?
A video from the ‘Learning from the Land’ series created by Catchment Sensitive Farming & Innovation for Agriculture
This is a great test you can do at home to understand how much rain water is running off your soils and whether it’s eroding precious topsoil and nutrients. Matthew Shepherd, Soil Biodiversity Specialist for Natural England, uses the humble tetra pack to show how soil samples from bare soil, arable and permanent pasture fields differ in their water holding capacity.
Healthy soil which has a good crumb structure or ‘aggregation’ throughout the topsoil and subsoil is able to store a large amount of water. It can be stored in all the nooks and crannies, as well as percolate around the soil ‘crumbs’ or particles deep into the soil. This gives plants access to water during drier weather in the spring and summer, making them more resistant to drought.
If the soil is poorly aggregated there are no nooks and crannies for the water to be stored in or percolate down through to the lower layers of soil. Instead it will move laterally through the topsoil taking nutrients and earth with it, far away from the farm and into water courses, literally leaking money and resources away.
There are various farm management practises for improving soil health and ‘aggregation’. Mob grazing is very effective in a mixed farming system, as it adds organic matter to the soil which feeds soil organisms that create aggregation, and it allows for rapid regrowth of grasses increasing their photosynthesis power and thus soil carbon. Find out more information about making your soil rain-ready here.
How about trying this test out with other local farmers growing different crops and grass leys so you have a wide variety of different soil samples? You can raid your recycling bins together for as many empty tetra pack cartons as possible!
- Tetrapack carton — re-use an orange juice or milk carton
- Soil sample block
- Collection jars
- Watering can
- Nitrate testing strips
Regular soil testing is helpful to understand how your soil aggregation changes when a new management practise is put in place to improve it. You could also try monitoring topsoil depth, water infiltration rate, and visual analysis of soil structure in the autumn and spring.