Soil characteristics and its relation with micronutrients availability
1. The particles diameter makes all the difference
Plants structure can be divided in two parts: the shoot system or aerial part with photosynthetic structures and the root system normally underground. The root system anchoes the plant to the ground and is mainly responsible for penetrating the soil to absorb water and minerals. However, the availability of the minerals will be closely related to the soil texture that changes the water storage dynamics and pH. The capacity of the soil to retain exchangeable cations can be measured obtaining the cation exchange capacity (CEC) index that indicates the immediately available nutrients for the plants. The five most abundant cations that get retained are calcium (Ca2+), magnesium (Mg2+), potassium (K+), sodium (Na+) and aluminium (Al3+). The stronger the soil is negatively charged the greater is the CEC index, expressed in centimoles of positive charge per kilogram of soil (cmol(+)/kg).
Basically, soil is composed of mineral particle, organic matter, water and air. The mineral particles define the soil texture according to its diameter size: clay = less than 0.002 mm, silt = 0.002 to 0.02 mm and sand = 0.02 to 2 mm. The proportion of those elements define the CEC from clay that is strongly charged negatively presenting a high capacity to attract and hold cations, to pure sand has the lowest CEC. Due to this, the characteristics of your soil will be taking into account for the elaboration of an optimal fertilization plan for your crops, when using the SMART fertilizer software. The combination of those three mineral particles will form the next types of soils:
2. Guide to understand what happens underground
The differences between soils will be mainly affected by the water retention capacity that they may have in any case and the presence of air pores after watering. The water penetration in pure clay is so slow (<0.13 cm per hour) that has a difficult habitability. However, when in mayor proportion but mixed with other type of soil, the recommendation would be to apply small water volume in a long time period so it can properly drain. Soils with predominance of clay takes time to dry after getting wet and can saturate all the soil pore spaces. Its tendency to compact hinders the seedling emergence, rot growth and plant reproduction.
On the contrary, water can fluently go through sandy soil (12.7 to 25.4 cm per hour) which eludes water accumulation. The water flow quickly washes the nutrients which reduces the capacity of the plants to absorb them. This type of soil is also prone to rapidly drying out, causing serious damage to plants health when drought is persistent.
Loam soil presents an equilibrate proportion of sand and silt, with a small percentage of clay. This combination provides an optimal aeration, nutrient retention and moisture retention for the best plant growth. Together with the fertilization advice you can obtain using the SMART fertilizer software, your crops would give you the greatest benefits.
3. How to improve the soil features?
Even if climatic factors affects the interaction between plants and water, the type of soil is also decisive for the plant available water. Soil factors such as texture are difficult to modify. However, improvements to its structure can be made, for example by manipulating the pore size distribution, which modulates water drainage, total water storage and water holding capacity. This soil structural porosity can be for example improved by adding organic matter.
Evaluation of the type of soil you are working with, together with an analysis of its morphology and soil resource inventories, you will be able to better handle your land with the highest efficiency.
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