Why are soils becoming more acidic?
- Use of fertilizers is generally acidifying the soil.
- Intake of organic effluents containing ammoniacal nitrogen.
- Nitrate leaching.
- Biological activity and carbon mineralization.
- Acidification around the rhizosphere, especially for leguminous crops.
- Pollution due to acid rain (industry or power plants, cars, etc.) or acid water drainage.
- Loss of nitrates through volatilization.
Impact of acidity on crop performance
- At a pH lower than 5.5, aluminum and manganese release lead to toxicity.
- Nutrient assimilation by the crops decreases with lower pH. At low pH, soil fertility is limited. At a pH of 5.5, only a third of the input is available for the crops. Acidity can lead to a loss of 120 kg/ha of ammonium nitrate for a wheat crop that receives 170 units of nitrogen!
- Acidification causes leaching of calcium, which decreases the structural stability of soil.
- Decreased field moisture capacity of the soil and increased impact of drought periods on crops.
- Lower vegetal diversity and lower production yield in pastures, resulting in lower quality and lower quantity feed for cattle.
Liming increases the alkalinity of soil
A higher pH helps to:
- Increase the amount of organic & natural fertilizers available for fields, vegetables, vineyards,etc. thus leading to a better crop yield.
- Improve the soil structure, thus increasing the potential production.
Carmeuse offers a range of liming products for enhancing and maintenance liming:
- Some regions have very acidic soils, which should be redressed in order to farm effectively. However, a maintenance amendment is generally required in most regions.
- The lower boundary is also called Objective pH, below which there is a risk of alumina toxicity (<5.5) and a high structural instability which can affect the growth of spring crops or survival of winter crops.
- Regular liming of fields allows maintenance of good field performance.
The three main effects of liming on soil :
1. Chemical effect : balances soil acidity
- Lime to raise the pH from 5.5 to 6.5 has a positive effect on the amount of nitrogen released from the soil. It also protects plants, thus limiting their ability to absorb toxic elements.
- In acidic soil, plants more easily absorb toxic elements such as aluminum or cadmium, which limits yield potential and crop quality.
Optimize fertilizing elements
- Soil treated with basic amendments offers a larger reservoir for essential nutrients (e.g. calcium) for plants. However, if only ammonia fertilizers are applied, the soil acidification will increase and toxic elements will be absorbed by the plants.
Enhance the organic matter in soil
- Liming enables better use of natural fertilizing elements in soil organic matter, which in turn allows less use of fertilizer.
2. Promotes biological activity
High pH in soil provides better aeration and moisture conditions, which is good for active microbial life.
3. Physical effect: improves soil structure
Liming encourages better roots development, thanks to a less compacted soil.
All together, these three effects of liming can increase potential production.
Greater production helps farmers to produce sustainably and to comply with the regulations on soil conservation.
More productive farmland, through the addition of amendments, maximizes cost-efficiency.
- Improves soil structure
- Optimizes the soil potential
- Boosts the effect of fertilizers
- Promotes biological activity
- Increases the organic matter in soil
- Protects plants
What is alumina toxicity?
A yellow color seen on the edge of leaves and an irregular growth of crops may be caused by alumina that is absorbed by crops at low pH.
How can we improve grassland quality for cattle?
Amending grassland helps to improve the quality of grass. Studies show that the leguminous share of a field will then increase, when compared to fields with low-quality grasses.
When is the best period for soil amendment?
It is better to spread an amendment before adding fertilizers and before seeding. Quicklime may be spread in the spring period, as it has a quick effect on soil. Calcium carbonate has a longer term effect, so it should be applied after the harvest or in the fall period. The fineness of the product will also influence the choice of period: a fine product dissolves quicker than a coarse product.
Why are Carmeuse products ‘natural solutions’ and how do they support sustainable agriculture?
Liming allows farmers to use less chemical fertilizer. It also helps to prevent pollution, due to excessive nitrogen leaching in the soil. As a result, liming should be seen as a foundation for intensive and sustainable agriculture.