When planning your crops’ irrigation or fertigation, besides knowing its water needs and your field’s climate condition, it is essential to know your soil, because characteristics that might seem insignificant, will in fact be deal breakers for efficient water and/or nutrient supply.
The granulometric distribution of the soil’s mineral fractions regarding their size is called soil texture. They can be majorly divided into 3 groups: clay, silt and sand. The clay fraction is the smallest one, with grains smaller than .002 millimeters, and the one with the highest rates of electrical charges. Silt particles vary between .002 and 0.05 mm and have almost no electrical charges. At last, there is the sand fraction, with absolutely no electrical charge and size between .053 and 2 mm. - Water retention capacity The idea of every irrigation system, considering the environment and the farmer’s budget, is to use as minimum water as possible. For that to happen, it is necessary for the soil to have a high capacity to retain water, allowing a longer period without irrigation between rains.
Clay soils manage to retain a great amount of water in the view of the fact that its small pores that can also turn into aggregates (as a result of their electrical charges) will comprise micropores, which are perfect structures to store water.
Sandy soils, due to their big pores that act mainly as a space for water conduction, have a low capacity of water retention, therefore needing more frequent irrigation. - Aeration Soil aeration is the process in which the soil exchanges its gases with the atmosphere and vice versa, and it is important because it enables root respiration and plant growth.
Sandy soils, given their pores size and particle organization, have good aeration, whereas clay soils - with small pores that work well as water storage but not gas exchange – has poor aeration.
This information will help guide the frequency of irrigation, for instance, the gap between water supply can’t be too long it will lead to dehydration but also can’t be too short, which will lead to water accumulation in clay soils and later on to the saturation of the whole system. If this happens, there is a massive waste of water, implicating in misuse of money and resources, surface runoff and soil erosion. - Drainage rates This is regarding soil’s ability to carry water and how smooth will the movement be, and is directly connected to the two characteristics that were introduced above.
Sandy soils have wider pores and consequently, a higher drainage rate, which helps distribute water and nutrients but might be risky since the water being drained might be lost.
On the other hand, clay soils have a very low drainage rate, therefore hold water for a longer period of time, but its distribution is quite slow. The same applies to nutrient distribution on fertigation systems.
If you would like to make sure your fertigation system is being correctly used and promoting the highest yields, try out the i-Plant Nutrition in which we can help you create the perfect fertigation plan for your crop! - Erosion susceptibility For most of the soil properties, we have talked about clay and sandy soils. However, when the subject of discussion is erosion, the silty soils stand out. That is due to the fact that sandy particles are too big to be transported through water, clay particles (although being small) can use their electric charge to form aggregates big enough that can’t be eroded as well but silt particles are just incredibly susceptive to erosion. Silty soils need special attention on irrigation and fertigation because their particles are not big enough like sand nor able to cluster like clay, being more prone to water erosion.
In i-Plant Nutrition your soil test is key to the creation of a personalized fertilization plan. We care about how every property of your field’s soil will react to irrigation, fertigation or any other form of fertilization. Check out our software here!