Soil Fertility and Nutrition

Soil Fertility and Plant Nutrition Area: soil samples, analytical balance and extracts in the laboratory

The Soil and Foliar Laboratory belongs to the Soil Fertility and Crop Nutrition Area, which is made up of a group of researchers dedicated to generating new information on the fertility and management of the country’s soils and on the nutrition of the various crops grown in them, at laboratory, greenhouse and field level.

The Soil and Foliar Laboratory carries out all kinds of chemical analyses related to crop nutrition, both for research and for teaching, and for many years now it has also offered these analyses as a service to agricultural producers in the country.

Analyses offered

  • Soil
  • Foliar
  • Growing media and water
  • Quality of organic fertilizers
  • Quality of mineral fertilizers

Soil, foliar, media and water analyses are used to make nutritional diagnoses in production systems; those of organic and mineral fertilizers assess the quality of the products used to correct the nutritional problems of crops. By providing analyses that are used as tools for nutritional diagnosis, the laboratory encourages the development of precision agriculture, which seeks to use resources according to the real needs of each site. And by analyzing the quality of the products used to correct nutritional problems, it helps growers choose the best options.

Current infrastructure

The Soil and Foliar Laboratory has a sample reception area, a preparation and drying area, laboratories for digestion and analysis, and a data processing area. It also has greenhouses for carrying out agronomic trials.

To carry out the analyses, the Soil and Foliar Laboratory is equipped with high-technology analytical instruments, including a microwave digestion system and the following:

Atomic absorption spectrophotometer with sample carousel
Atomic Absorption SpectrophotometerDetermines the concentration of metallic elements by atomising the sample in a flame and measuring the radiation absorbed at the characteristic wavelength of each element. It is used to quantify calcium, magnesium, potassium, iron, copper, zinc and manganese in soil extracts and plant tissue. It is a reference technique, recognised for the accuracy and reproducibility of its results.
Inductively coupled plasma optical emission spectrometer
Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES)Uses a high-temperature argon plasma to excite the atoms in the sample and measures the radiation they emit at specific wavelengths. It allows around twenty elements to be determined simultaneously in a single run and over a wide concentration range, which supports the laboratory’s capacity to process high sample volumes.
Inductively coupled plasma mass spectrometer with workstation
Inductively Coupled Plasma Mass Spectrometer (ICP-MS)Ionises the sample in an argon plasma and separates the ions according to their mass-to-charge ratio. It is the most sensitive instrument in the laboratory, with detection limits in the order of micrograms per litre. It is used to determine micronutrients and to monitor potentially toxic elements such as cadmium, lead and arsenic.
Flow injection analyser with reagent pumps
Flow Injection Analyser (FIA)Automates colorimetric wet chemistry methods. The sample is injected into a continuous stream of reagents and the reaction is quantified in line by spectrophotometric detection. It is applied to the determination of nitrogen, phosphorus and other soluble forms, with a high analysis rate, good repeatability and lower reagent consumption than manual procedures.
Nitrogen auto-analyser
Nitrogen Auto-analyserDetermines total nitrogen in soils, plant tissue and fertilizers by combustion, following the Dumas method: the sample is oxidised at high temperature and the nitrogen released is quantified by thermal conductivity detection. Compared with the Kjeldahl method, it shortens analysis time and avoids handling concentrated acids.
Carbon and nitrogen auto-analyser
Carbon and Nitrogen Auto-analyserDetermines total carbon and nitrogen simultaneously by combustion. The resulting C/N ratio indicates the rate at which organic matter mineralises and is used to assess the quality of soils, organic fertilizers and compost.

Quality Management System

The Soil and Foliar Laboratory works under a Quality Management System in order to provide and guarantee reliable, high-quality testing services, according to the agronomic needs of its users and for the benefit of the national agricultural sector.

The services and activities of the laboratory are carried out by competent personnel, impartially and following the guidelines of the Quality System, free from any pressure that might compromise that impartiality.

The Laboratory has put in place internal controls to ensure the quality of its results. It also takes part in the national sample exchange programmes of the Costa Rican Network of Soil Laboratories (CRISOLAN) and in WEPAL, the international programme run by Wageningen University in the Netherlands.

Documents and links