Soil Acidity and Amelioration
Many cropping areas are significantly affected by soil acidity which occurs as a result of constant cropping, loss of organic carbon, the leaching of nutrients, and the misuse and overuse of fertilizers. As such, soil acidity severely affects crop productivity. This is because as hydrogen ions increase in the soil, the soil’s capacity to release essential nutrients for growth is impeded. At low pH levels, macronutrients such as calcium are deficient, whereas, at high pH levels, micronutrients such as zinc are deficient.
Soil acidity can be largely improved by the application of a liming material, which works to offset acidity by raising the pH, consequently increasing nutrients that can become plant available. The critical threshold of soil acidity is 5. Below this threshold, aluminum becomes plant available and toxic. At an optimum pH of around 6.5 aluminum is not toxic, and simultaneously other soil nutrients become plant available for uptake by the roots.
In understanding the effects of soil acidity on crops, it is important to note that the tolerance levels to soil acidity of different crops can significantly differ. Typically crops require a pH range of 5.5 to 6.5 (CaCl) for optimal growth. However, the pH scale at which crops grow differs significantly. For example, chilies and sweet potatoes are able to tolerate slightly more acidic soils whereas many horticultural crops, such as onions, carrots and cabbages are not able to withstand acidic soils and grow optimally in neutral soil.
In order to rectify soil acidity, you need to raise the soil pH, of which agricultural lime can be applied. The benefits of liming are immense, it works to increase nutrients that become available to the plant whilst reducing aluminum and manganese toxicities in the soil allowing for greater plant uptake of the major plant nutrients, as well as adding calcium and (or) magnesium to the soil and significantly improving the soil environment for the beneficial living microorganisms. These microorganisms promote the rapid breakdown of organic materials in the soil, releasing nutrients for optimal crops growth. Furthermore, raising soil pH improves the soils’ ability to store water promoting the crop’s root development, and particularly for leguminous crops, improving soil acidity helps to better the nitrogen fixation by legumes.
Different types of agricultural lime
The application of agricultural lime is the most widely known and economically viable option for addressing soil acidity. It can be applied in many forms; although, powdered lime tends to be the most common agricultural lime available. However, micronized, and granulated lime has become available within the market offering an efficient and effective alternative to powdered lime.
At Damara Bio-Agri we stock MicroCal, a micronized and granulated calcitic lime, and MicroDol, a micronized and granulated dolomitic lime. The micronization and granulation of the lime allows for a mean particle size of 40 micron, which works to increase the reactivity of the lime as well as the neutralizing capacity. As well as this, the fine particles are bound together with a biological lignosulfonate binder which works to increase both the granulation and efficiency of the product. Thus, the benefits of granulated lime include the ease of transportation as well as application, that being, lime can be applied either before or after planting. This is due to the effective reactivity of the product which has an immediate effect on neutralizing soil acidity resulting in rapid and sustained pH correction.
For more information please get in touch with us
+263 772 334 764
