Natural Resources

Natural Resources Area: sensors installed in a soil pit, soil map of Costa Rica and soil samples

History of the area

The Natural Resources area began at the Centre for Agronomic Research (CIA) as a section in 1995. In 2000 the area set up the Natural Resources Laboratory (LRN), devoted to teaching, research and community outreach through its activities, projects and staff. The LRN is now established as a research niche in the main natural resources of Costa Rica, and also provides services in soil physics, soil genesis, classification and mapping, and soil management and conservation.

It was created to study the soil as a natural resource and its interaction at landscape and watershed level, taking in its relationship with other resources such as water, forests and minerals, without losing sight of the link between soil and agroecosystems.

Research

The LRN focuses on improving the country’s soil inventory and on assessing, developing and improving management practices for this vital natural resource, as a means of preserving the natural resources of Costa Rica.

The most significant activities carried out over the years include the following:

  • Measurement of the impact of erosion on the productivity of agricultural soils.
  • Inventory and mapping of the soil resource in Costa Rica.
  • Watershed-level studies for the assessment of aquifer recharge areas.
  • Semi-detailed soil studies and mapping in different regions of Costa Rica.
  • Development and validation of methods for physical soil analysis in Costa Rica.
  • Research on elevated carbon dioxide (eCO2) in volcanic landscapes of Costa Rica.

Teaching

LRN staff take part in undergraduate teaching at the schools of Agronomy, Animal Science and Agricultural Economics of the Faculty of Agrifood Sciences, at the Guanacaste and Atlantic regional campuses, and at postgraduate level in the Graduate Studies System in Agricultural Sciences and Natural Resources.

The LRN also runs short courses for professionals, technicians and farmers, and supports students from other undergraduate and postgraduate programmes of the UCR, both formally and informally. It further collaborates in teaching and research with international institutions in North and South America.

Community outreach

As a core part of university work, LRN staff answer enquiries from small and medium-sized farmers on soil management and conservation, mechanisation and tillage, land classification for agriculture, and the management of soil and water resources.

The LRN also supports activities such as the University Community Work programme (TCU) and requests for physical soil analyses, which are provided free of charge, from producer associations and other members of the community with limited resources.

Services

The LRN generates income through its services, analysing the physical properties of soils and their hydrological and mechanical behaviour. The services available are the following.

Physical soil analyses

  • Texture, particle size distribution curve and grain size of the coarse soil fraction.
  • Bulk density, particle density and total soil porosity.
  • Gravimetric soil moisture.
  • Soil hydraulic conductivity.
  • Soil moisture retention and available water.
  • Soil moisture retention curve.
  • Soil aggregate stability.
  • Coefficient of linear extensibility of the soil.

Contract research, advice and consultancy

  • Physical soil properties and their implications for agriculture.
  • Soil genesis and classification.
  • Soil management and conservation.
  • Application of Geographic Information Systems (GIS) in agriculture.
  • Assessment of physical properties in the field using electronic sensors.
  • Determination of the effect of tillage, erosion and compaction on soil productivity.
  • Integrated water resource management.
  • Studies on water saving and water use efficiency in agricultural systems and watersheds.
  • Modelling and scenario analysis to support planning and decision-making in water management and agricultural production.

Laboratory images

Sedimentation cylinders lined up during a texture analysis
Texture analysis by the hydrometer method.
Soil samples arranged in rings on a plate, seen from above
Samples prepared for the moisture retention test.
Soil cores in metal rings arranged on a plate
Soil cores for the bulk density and porosity tests.
A researcher operates the laboratory pressure plate apparatus
Pressure plate apparatusThe sample is subjected to known tensions and the water retained by the soil at each one is measured. This is the test from which the moisture retention curve is built.
Four moisture retention curves of Costa Rican soils
Moisture retention curvesResults of the test on four Costa Rican soils. Each point corresponds to an applied tension and the line is the fitted model; the difference between curves shows how much water remains available to the crop.

Field images

Drone photograph of a field trial with soil pits and measuring equipment
Aerial view of a field trial: drone photography helps locate the soil pits and plan the sampling.
A researcher records data with a tension infiltrometer in a coffee plantation
Measurement of soil hydraulic conductivity in a coffee plantation.
Rings of known volume and sampling tools on the ground
Rings of known volume and the tools used to take undisturbed samples.
A researcher describes the horizons of a soil profile
Description of a soil profile in the field, the step before its taxonomic classification.
Sample taken with an auger, laid out next to a measuring tape
Auger sampling: the sample is laid out and measured to record the depth of each horizon.
Sensors connected on the wall of a soil pit
Sensors installed in a soil pit for continuous recording of soil moisture and temperature.

Documents and links