Spectroscopic techniques have had a boom since most methodologies allow large areas of land to be adequately studied. For this reason it is necessary to review within the current spectroscopic techniques used in soil analysis which would be the most appropriate technique for my project.
We well know that, in order to perform an analysis of traditional soils , it involves physical and chemical characterization of the soil whose information obtained allows us to increase productivity , as well as to seek the appropriate agricultural practices to achieve high soil quality . Basically, these analyzes have allowed the promotion of agricultural practices such as irrigation, fertilization, liming of soils under forest and converted into agricultural land.
The physical and chemical analysis of soils is commonly based on volumetric, gravimetric, visible spectrophotometry, X-ray diffraction, atomic absorption spectroscopy (EAA), etc. , where each of these provides in situ and in vitro values of each parameter of agricultural utility helping us to know the quality of the soil. We can observe an example in the Mexican Standards, such is the case of NOM-021-RECNAT-200 , which establishes the specifications of fertility, salinity and classification of soils, studies, sampling and analysis. However, what is the problem with most of these techniques?Most of these procedures consume large amounts of time, some are expensive and generate large amounts of environmentally polluting waste.
Given the growing demand for databases for monitoring soil status, there is a need for low-cost tools. And soil spectroscopy has proven to be a fast, low-cost, environmentally friendly, non-destructive and reproducible tool, settling on a high standard for this field of continuous growth.
It is necessary to review the current spectroscopic techniques used for soil analyzes to assess their versatility in estimating the physical and chemical parameters of the soil and thus, to suggest which of the modern spectroscopic techniques would be the most convenient to incorporate into the analysis services , of which I will talk a little about them below.
- UV-Visible (UV-VIS)
Used for the study of soil organic matter (MOS), it has allowed us to indicate the quality of soil humic substances, as well as helping us to characterize the organic matter extracted from a soil solution.
- Infrared (IR)
It is relatively quick and easy to use, requires little sample preparation, this technique has been able to characterize the concentrations of clay minerals, helps us to demonstrate the enrichment of chemically recalcitrant structures.
Applying visible near infrared analysis, it has been possible to predict soil properties such as color, mineral composition, MO, water content, form, amount of iron, carbonates, soluble salts, particle size, among others.
- Atomic Absorption
It is the classical technique to determine total base and minor soil elements, for example, arsenic in soils. Mineralized YP of soils treated with organic amendments.