What is limestone soil?
The calcareous soils are characterised by their high calcium carbonate content. This composition gives the soil a specific texture and properties such as a generally high pH, which directly affects nutrient availability and microbial activity.
Where is limestone soil found?
The calcareous soils form in arid and semi-arid climates, typical of southern Spain. These horizons may be those present in the fairways of golf courses in these climates that have been built on top of the original soil. They can be determined by means of a laboratory test.
These soil profiles are usually cemented by carbonate minerals, they are calcic or petrocalcic horizons (Soil Survey Staff, 2010). The Calcium and Bicarbonate ions can come from the parent material or even from the atmospheric dust (Rabenhorst et al., 1991; Robins et al., 2012), which are altered in situ. As the soil dries out, carbonates and bicarbonates concentrate and precipitate (Birkland, 1999; Gile et al., 1966). If the soil is calcareous, it will tend to exhibit pH possible iron chlorosis and even difficulty in phosphorus absorption.
The carbonate minerals precipitate together with roots and soil particles, gradually reducing the pore space as the soil becomes cemented (Monger et al.,1991). The cemented horizons with calcium carbonate restrict root growth and vertical movement of water (Cuningham and Burk, 1973), although some calcareous horizons can be well drained, especially when associated with sandy soil fractions (Baumhart and Lascano, 1993).
The carbonates in agricultural soils can from irrigation water as well as lithological provenance. The carbonate accumulation from water irrigation is often associated with sodium contentthe SAR or RAS(ratio of sodium adsorption) of irrigation water is usually adjusted to counteract Calcium precipitating as carbonates, which would increase the exchangeable Sodium over Calcium and Magnesium (Bower et al., 1968; Miyamoto, 1980; Rhoades, 1980).
In the golf industrythere is a belief that irrigation waters with high bicarbonate contents can lead to -similar to agricultural crops to calcareous accumulationsresulting in reductions in porosity and conductivity hydraulics (Carrow et al., 1999; Simmons, 2010). In other words, the salts induce this porous soil decreasesuggesting that the use irrigation water with contents of bicarbonate concentration above 13.3 mmol/l for one year, would decrease leakage. Other researchers claim that the use of high bicarbonate but low sodium water reduces permeability (Harivandi, 1999) and suggest the use of irrigation water treatments.
Studies carried out by Glen Obear and Solder, 2015, on 28 soil samples of greens, found no evident relationship to show that irrigation with water with a high bicarbonate content is sufficient to produce calcareous horizons in them, contrary to what was thought and occurs in agricultural soils. In other words, the particular characteristics of the growth of the greens, intense maintenance, high rates of soil respiration, high porosity, sandy profile, etc., give rise to a different behaviour to that which would normally occur in other soil profiles and agricultural crops.
How to detect and monitor soil activity
Calcareous soils are extremely reactive, there are different types of equipment that can monitor soil activity and its impact on the crop.
Direct soil EC meter
Laqua Twin Ca+ Calcium Ion Meter
TDR Infrared Sensor
POGO sensor for comprehensive analysis
If you want to know more about these instruments, please write to us at firstname.lastname@example.org
Soil Differentiation: Chalky vs. Calcareous Soils
The calcareous soilscharacterised by their rich calcium carbonate (CaCO3) composition, vary in their pedogenic origin. Unlike the limestone soilswhich are formed directly from limestone rocks composed mainly of calcitecalcareous soils can originate from a variety of processes, including the aeolian accumulation of carbonates or the alteration of other carbonate rocks. This distinction is crucial in understanding their physico-chemical properties, as described in the studies of White and Brantley (2003) and Monger and Gallegos (2000), who explore the implications of the carbonate solubility and its impact on soil structure and chemistry.
Management and Fertilisation Strategies for Alkaline Soils
Addressing the management of soils with high alkalinity on golf courses, both calcareous and chalky soilspresent challenges in the micronutrient availabilityespecially iron, leading to phenomena such as iron chlorosis. The application of chelated fertilisers and acidic amendments is essential to mitigate the low solubility of micronutrients. In addition, the texture of calcareous soilsThe often sandier, often sandier texture facilitates better drainage compared to the finer, more compact texture of limestone soils, which require more rigorous water management and possible amendments to optimise soil structure and permeability, key to maintaining soil health and permeability. aesthetics of the greens.