What information do agricultural soils analyses give us and when are they done?
Agricultural soils analyses are an essential part on which we base any agronomic management program in agricultural production. Following are some of the aspects we are going to discuss with this type of analysis:
- Fertility of our soil
- Availability of its nutrients
- Changes to make in pre-sowing or pre-planting
- Creating a diagnosis when faced with a nutritional problem in my crop
Without a proper soil analysis, we would be blind when making decisions about fertilization, using too little, preventing us from achieving our harvest goals, or using too much, in this way increasing the price of the production process, and we may create imbalances in the structure of the soil, in addition to causing contaminating leaching.
The efficacy of soil analyses will depend to a large extent on how representative it is. It will be of little use if the soil sample to be analyzed only represents 10% of a ranch, and we recommend doing an analysis for every 15-30acres of area.
All irrigation and nutrition management must have as its starting point a soil analysis in addition to an analysis of irrigation water; in this way we will be able to have access to information that will allow us to carry out the best irrigation and fertilization program possible under our conditions.
What parameters are analyzed in soil analyses?
The information provided by soil analyses that we should not disregard before making any decision is the following:
Texture. This parameter will tell us what our best irrigation strategy will be for getting the most benefit out of the water provided. In terms of nutrition, it will indicate in broad terms the salt content and will give us an estimate of the nutrient retention capacity. All this will indicate which elements must be added, in which dosage, and which chemical application method is most advisable.
pH. It will indicate the reaction the soil will have, whether it is acid or alkaline. This feature will give us an idea of the availability of elements in the soil solution such as phosphorus and micronutrients, which are very sensitive to variations in this factor.
Electrical conductivity. It indicates the salinity of the soil. Depending on this value, we will know whether the crop to be sown/planted tolerates our soil or the best fertilization and irrigation strategy for achieving the best results.
Nutrients available to the plant. Whether they are macronutrients (nitrogen, phosphorus, potassium, calcium, and magnesium) or micronutrients (iron, boron, manganese, zinc, molybdenum, and copper), we should know in which proportions we can find them in our soil, always speaking about their available form, because it will be of little use to know the total amount there will be of one of them if then only a minimum percentage is found soluble to enter the roots.
In the end, without these four points, it would not be possible to make a good fertilization recommendation, whether as a basal dressing/cover or a general planting for the entire year.
When should we do the soil analysis?
The right time to take soil samples is after the harvest. In this way, we will see the condition of our soils for the next season; and so we can do a correct fertilization and crop management.
Nevertheless, we can also analyze the soil on our farm faced with specific problems that we can detect in the crop, in order to evaluate whether there could be a correlation with the soil conditions.
The importance of a correct interpretation
Soil analyses not only are going to tell us the fertilizer capacity of our substratum; they will also give us an idea of the availability of the macronutrients and micronutrients in it, a factor in which the pH, the active lime, the texture or the organic material figure, among others.
In order to improve the way the plant uses the soil nutrients, once we learn the reason why they are not available, we have to make a change before the sowing or planting. These are some examples of the reasoning we can find:
With a high pH. Higher than 8, there are many nutrients that are not available, such as phosphorus or most of the microelements. Therefore, it is essential to lower said pH with the addition of organic matter or applying acid or super acid liquid solutions.
Acid soils (pH between 4 and 6). The availability of phosphorus or microelements is good; however, we have deficiencies in calcium and magnesium that will hinder the proper development of our crop. The soil analysis will give us sufficient tools for calculating which source of calcium and magnesium is most suitable and the amount to be used.
Saline soils and soils with compaction due to sodium. The only way to handle this difficulty is managing data on the levels of electrical conductivity, toxic ions (chlorides and sodium) and chemical balances with non-toxic ions (nitrates, and the rest of the cations).
At AGQ Labs, we have a modern Soil Factory Lab capable of doing over 300 samples per day, using the latest technology and a fully automated analytical process. Furthermore, we have a large team of agricultural engineers accustomed to interpreting the data resulting from the analyses, translating all that information into the right plan for managing your crops.