Coffee Cultivation and Climate Change_Peterlunger&Turello_L2 - Agronomical Techniques in Coffee Cultivation

Plant Functions

  • The main plant function is photosynthesis.

    • Photosynthesis uses the sun's energy to produce sugar (glucose initially). This sugar is the plant's primary food source.
    • Fertilizers assist plant nutrition, but the main food for plants comes from photosynthesis.

  • Respiration:

    • It is a metabolic process in mitochondria.
    • Respiration uses sugar to produce energy for various processes:
      • Root growth.
      • Water absorption.
      • Fluid formation and maturation.
      • Defense against pests.

  • Transpiration:

    • It is similar to the circulation system in animals.
      • Water is absorbed by the roots, translocated to the trunk and leaves, and then released into the atmosphere.
    • This water movement cools the leaf temperature and translocates metabolites.
    • Xylem transports water from roots to stem and leaves (upward).
    • Phloem transports sap (water, sugars, amino acids, plant hormones) from leaves to the trunk, roots, and fruits.

  • Translocation of assimilates involves intelligent allocation of resources based on environmental conditions and plant needs.

  • Annual Cycle of Plants:

    • Sugars from leaves go to:
      • Shoot apex for new growth.
      • Root apex for root exploration.
      • Berries for reproduction.
      • Reserve tissues (storage) that accumulate starch and proteins.

Irrigation

  • Plant water use:

    • To produce 1 kilogram of dry matter, plants need an average of 500 liters of water.
    • If rainfall is insufficient (less than 1200 mm per year), irrigation is necessary.

  • Arabica vs. Robusta:

    • Arabica roots are deeper, making them more drought-resistant.
    • Robusta roots are more superficial and generally need more water due to their vigor.

  • Mulching reduces evaporation from the soil.

  • When to Irrigate:

    • Balance rainfall with evapotranspiration (80-200 mm per month).
    • 1 millimeter of rain equals 1 liter of water per square meter or 10,000 liters per hectare (10 tons per hectare).
    • Irrigation is crucial during flowering and berry maturation.

  • Irrigation systems:

    • Sprinkler Systems:

      • Semi-fixed.
      • Transportable.
      • Pivot (large structure irrigating 50-100 hectares).

    • Drip Irrigation:

      • Uses plastic pipes (1.5-2 cm diameter).
      • Low pressure (1 bar).
      • Drippers release 2-8 liters of water per hour.
      • Dripper spacing depends on soil type (closer in sandy soil, more distant in clay soil).

    • Micro sprinklers under the canopy.

    • Fertigation: Adding fertilizers to irrigation water.

    • Irrigation can also leach salts from saline soils.

  • Water Sourcing:

    • Wells provide clean water.

    • Rivers often need filtration.

    • Rainfall can be collected in ponds (lined with plastic).

    • Water pumped from wells is typically stored in reservoirs, which also collect rainwater.

    • Large plantations in Brazil use reservoirs that can span hundreds of hectares.

    • Small farmers may dig holes and fill them with mulch to store water and maintain soil humidity.

  • Testing Soil Humidity

    • Sensors (TDR - time-domain reflectometry) measure the percentage of water in the soil.
    • Plant water status:
      • Leaf water potential can be measured using a pressure chamber.
      • This indicates the level of plant dehydration.

  • Irrigation Timing:

    • Nurseries: Irrigate plants in pots once or twice a day during hot, dry periods.
    • Young plants: Need approximately 5-10 liters per plant per week (roughly 10 mm of irrigation per week, equivalent to 100 tons of water per hectare).
    • Plants in production: Irrigate every 10 days with 25 mm of water, particularly during flowering, berry set, berry filling, and hardening (16 weeks after bloom).
    • Irrigation is typically reduced or stopped during winter.

Pruning

  • Types of Branches:

    • Vertical (orthotropic).
    • Lateral (plagiotropic) - where production occurs, typically on one-year-old wood, with a biennial bearing.

  • Pruning extends the orchard's production cycle (from 7-8 years to 12-14 years).

  • Process

    • Cut the trunk at a 30-cm height, with an inclination to prevent water collection.
    • Allow suckers to emerge and select either a single stem or multiple stems.
    • Ensure proper light penetration by equilibrating stems and removing central branches.

  • Training Systems:

    • Agobadia: Bending the single stem and fixing it to the soil to encourage vertical stems and lateral growth.
      • Allows plant to produce more stems.

  • Rejuvenation

    • Alternate cutting of trunks in different rows to maintain some production during rejuvenation.

  • Coffee Pruning Videos:

    • Pruning is typically done at knee height, cutting at an angle to prevent water accumulation.
    • Innovative pruning methods (Beaumont Fukunaga) involve stumping the tree completely and result in higher yields.
    • Canopy management involves opening up the tree and reducing superfluous foliage to direct energy into bean swelling. It includes removing suckers and secondary growth.

Canopy Management

  • Involves interventions to regulate vegetation, especially with abundant fertilization that can lead to dense canopies.

  • Objective: To equilibrate vegetation and allow light penetration within the canopy, which can influence flower formation.

Soil Management

  • Weed Control:

    • Weeds compete with coffee plants for nutrients.
    • Mulching helps suppress weeds and reduce soil evaporation.
    • Alternatives: growing ground cover (Gravinaceae and Leguminosa) which also helps with erosion control.
    • Mechanical methods includes slashing or string trimmers or herbicides although herbicides are not compatible with organic production.

Harvest

  • Manual vs. Mechanical

    • Manual harvesting selects berries at similar degree of maturation.
    • Mechanical harvesting is less selective, requiring selection of optimal time with the majority of berries at ripe or overripe.
    • Mechanical harvesting reduces the demand of human labor.

  • Gleaning is crucial to prevent coffee berry borer infestations.

  • Hand Harvesting Videos

    • Handpicking is essential for selecting ripe coffee cherries to obtain the best flavor.
    • Cherries are pulped, fermented, and washed to sort beans by density.

  • Additional insight from Luca:

    • It is essential also to provide a good logistic to the harvester to reduce costs.
    • Mechanical is more affordable in large, level plantations in Brazil where the technology was developed.