Every day for more than 20 years, an average of 2,000 hectares of irrigated land in arid and semi-arid areas across 75 countries have been degraded by salt. Salt degrades soils and saps crop productivity, increases poverty, drives economically precarious rural communities to the cities, undermines biodiversity, and harms soil’s ability to store carbon.
The world needs to sustain agricultural production, and potassium inputs will be vital in achieving that. However, it is crucial to leverage fertilisers with a low salt index to stop and reverse salt-induced land degradation. The SOP has the lowest salt index compared to potassium sources such as potassium chloride, potassium nitrate and sodium-potassium nitrate. Consequently, it has the most negligible impact on soil salinity. It represents the best potassium source for salt-affected soils or at sites where salinity could be a risk through high fertiliser dressing or low water availability.
Soil salinity: Threat to food security and sustainable development
Inadequate drainage or excessive evaporation from agricultural fields leads to an accumulation in the soil. Whenever the evapotranspiration exceeds the water input by rainfall and irrigation, the salts dissolved in the rain or the irrigation water accumulate in the upper soil horizon. Salt concentrations can increase toxic levels and change fertile agricultural land into barren and unproductive wastelands without sufficient drainage.
Climate change exacerbates the accumulation of salts in soils due to dryland expansion, water scarcity, as well as a rise in sea levels, causing saltwater intrusion in coastal areas. In these cases, salts gradually accumulate in the soil, starting as a small hidden problem and progressing to severe degradation if not adequately managed. Soil salinity is one of the impacts of climate change on coastal agricultural land, as rising sea levels have increased salinity from 1 to 33% over the last 25 years. These salt problems may be found in many parts of the world.
Salt-affected soils have severe impacts on some of the ecosystem services soils usually provide, which are critical for supporting human life and biodiversity, leading to various consequences, including decreased agricultural productivity, water quality, soil biodiversity, and increased soil erosion. Due to this, the salinisation of soils has tremendous challenges for crop production and soil productivities, resulting in uncertain and unstable livelihood security, low economic returns, and poor quality of life in developing lower-income countries.
How can Colluli help mitigate the effects of soil salinity?
Colluli will be a significant, global production centre of premium, chloride-free sulphate of potash (SOP) fertiliser. Chloride containing fertilisers may exert a negative side effect on the cation balance in plant shoots. The preferred form of potash for conditions prone to salinity is SOP because it is virtually free of chloride and has a low salt index compared to other potassium sources such as MOP (muriate of potash) and NOP (nitrate of potash).
Sulphate of potash has the lowest salt index of 46 compared to potassium sources such as potassium chloride, potassium nitrate and sodium-potassium nitrate, consequently has the most negligible impact on soil salinity and represents the best potassium source for salt-affected soils or at sites where salinity could be a risk through high fertiliser dressing or low water availability. Mainly where leaching is restricted or in production systems with high fertiliser applications and short production cycles with salt accumulation in the root zone, sulphate of potash is, without doubt, the best potassium source due to its low salt index.
Moreover, In the soil, the sulphate of potash immediately dissociates into the cation K+ and the anion SO42- nutrient forms directly available to the plant. As no oxidation or reduction processes are involved in releasing these nutrients into the soil, an application of SOP has no impact on soil pH, causing little to no effects on soil biodiversity. To further mitigate soil salinisation, Colluli can also leverage gypsum deposits in its resource. Gypsum can leach soluble salts out of the topsoil deeper into the soil profile, away from the zone in which crop roots will be growing. Due to this, Colluli produced gypsum could potentially help soil restoration efforts in Eritrea and surrounding countries facing increasingly visible soil salinity challenges (particularly Ethiopia and Sudan).
As Africa’s most advanced SOP project, the Colluli could provide a significant source of accessible potassium fertilisers needed to reverse the region’s negative soil salinity trends. Colluli will be a part of that equation by providing 200 years of carbon and chloride-free fertiliser nutrients essential for food security globally.