Balancing your soil’s pH over winter for future success
With crops harvested and fields lying fallow, winter provides an opportunity for farmers to address soil health issues such as soil pH ahead of the next growing season without affecting standing crops.
Balanced soil pH leads to:
- Enhanced nutrient uptake: When pH is balanced, nutrients in the soil become more readily available for plant uptake, leading to healthier crops.
- Optimal microbial activity: Beneficial microbes thrive in a pH-balanced environment, enhancing nutrient cycling and plant health.
- Reduced metal toxicity: At certain pH levels, toxic metals like aluminium can become soluble and harm plants. Balancing pH helps lock these metals in an insoluble form.
The pH level of the soil therefore directly influences the availability of essential nutrients to plants, thus impacting the crop’s health and yield.
Understand your soil’s current pH:
Before you can balance your soil’s pH by making any amendments, you need to understand where it currently stands by testing the soil’s current pH level.
Use a soil testing kit or send a soil sample to a laboratory to get an accurate pH reading. See here for further information on soil testing.
The pH scale ranges from 0 to 14, with a pH level of 6.0 to 7.5 being considered neutral, anything below 6 is acidic and anything above 7.5 is alkaline.
Acidic or alkaline?
Following soil testing , it is likely the results will show the soil to be too acidic or too alkaline, both of which will need altering to become neutral.
Acidic soils (pH < 7.0): Common in areas with high rainfall such as Snowdonia, the Lake District and the Scottish Highlands.
To raise the pH of acidic soil, consider adding agricultural lime.
Alkaline soils (pH > 7.0): Prevalent in arid regions, which in the UK is typically the eastern side of the country.
To lower the pH of alkaline soil, consider adding sulphur-based amendments or organic materials like straw.
See here for further information on incorporating straw into the soil.
Applying lime to raise pH
For acidic soils, agricultural lime (calcium carbonate) is commonly used to raise soil pH. Dolomitic lime can also be used if your soil is magnesium deficient.
Winter is an excellent time to apply lime because it gives the lime ample time to react with the soil as it takes a few months to adjust the pH.
To apply, spread lime evenly over your field using a lime spreader or broadcast spreader, and then incorporate it into the soil using a tiller or disc harrow.
Using sulphur to lower pH
For alkaline soils, sulphur compounds, such as elemental sulphur or aluminium sulphate, can help lower pH by acidifying the soil.
Like lime, sulphur needs time to adjust the soil’s pH, making winter a perfect time to take action.
To apply, sulphur should be broadcast applied. However, ensure that you don’t overapply, as excessive sulphur can harm soil health.
In extreme cases of soil alkalinity, consider growing crops such as beets and sprouts that can tolerate a higher pH rather than continually fighting to lower it.
Additional aids in balancing soil pH
Tilling: For more immediate results and to optimise the benefits of soil amendments, it’s recommended to till the amendments into the top 4-6 inches of soil.
This deeper incorporation technique promotes a more uniform distribution of the amendments, facilitating more immediate interaction with the soil particles.
Consequently, tilling ensures a swifter pH adjustment period, setting the stage for healthier plant growth in the subsequent season.
Straw spreading: In addition to soil treatments such as lime and sulphur applications, it’s also beneficial to cover the soil with organic mulch, such as straw.
This protective layer serves multiple purposes.
- It aids in maintaining consistent pH levels by acting as a buffer against sudden environmental changes.
- It safeguards the soil from erosive forces like wind and heavy rainfall, which can otherwise wash away the top fertile layer of the soil.
- Lastly, as this organic mulch decomposes over time, it contributes organic matter to the soil.
This decomposition not only enhances the soil’s texture and water retention capabilities but also releases compounds that can subtly influence and stabilise the soil pH, promoting an environment conducive for plant growth
Further information straw spreading is available here.
In conclusion, winter provides a unique opportunity for farmers to address and balance soil pH.
After applying either lime or sulphur, farmers should re-test the soil’s pH during the latter part of winter or onset of spring. This ensures that the pH aligns with the targeted levels, while still providing time to make further adjustments if needed.
With the right amendments and techniques, you can set the stage for a successful crop yield in the upcoming season.