Irrigation Management in Cocopeat

Important Definitions

• Steering the crop: Techniques to control crop production and growth direction.
• Vegetative growth: Characterized by thick stems and strong leaf growth; poor fruit set due to energy diversion from fruiting.
• Generative growth: Features thin stems, high fruit set, smaller fruit size, and slower plant growth.
• Balanced crop: Strong plant growth coupled with good fruit growth and size.

Purpose of Irrigation

• Provides essential water for plant growth.
• Facilitates transpiration to cool the plant.
• Helps drain excess salts from the root zone.

Greenhouse Crop Irrigation Requirements

• Basic formula: 100 joules of light correlates to 300 mL of irrigation per square meter.
• Breakdown of irrigation needs:
  • 100 mL for plant growth
  • 100 mL for transpiration
  • 100 mL for drainage runoff and electrical conductivity (EC) regulation.

Irrigation Application for Tomatoes

• Link irrigation to accumulated light levels; time-based irrigation is insufficient.
• On low light/cloudy days, timed irrigation may be necessary to maintain EC control.

Critical Volume of Irrigation

• Cocopeat growbags have a water infiltration threshold; exceeding it leads to false drain, where water flows around the sides rather than through the slab.
• To prevent false drain, irrigation should not exceed 300-450 mL per square meter per application, equating to 2 L/hr drippers for limited durations.

Irrigation Frequency

• Short, frequent irrigation sessions are preferable to larger, infrequent ones.
• Adjust irrigation volumes throughout the day, maintaining a consistent volume while varying timing based on light levels.

Cocopeat Volume for Crop Steering

• Ideal cocopeat volume: 8-10 liters per square meter of greenhouse.
• Growbag dimensions: 1 meter long x 15 cm wide x 10 cm high.
• Less than 8 L leads to generative crop behavior; more than 10 L causes vegetative growth.

Importance of Drying

• Cocopeat must dry at night to oxygenate the root zone and stimulate hormone production for desired growth direction.
• Moisture content impacts crop steering:
  • Drying 8-10% at night encourages generative growth.
  • Drying less than 6% promotes vegetative growth.

Timing of Irrigation

• Begin irrigation 1-2 hours after sunrise for effective water absorption.
• The last irrigation should allow drying time overnight, ideally 2-3 hours before sunset.

Drainage Importance

• Daily drain (runoff) regulates root zone EC, affecting osmotic pressure and water uptake.
• Ideal drain rates:
  • 30-40% daily average to maintain target EC.
  • Up to 50% drain during peak sunlight to manage high water absorption and nutrient uptake.

Monitoring EC Levels

• Regular EC monitoring is essential for effective crop growth steering.
• Adjust irrigation to correct high or low drain EC levels gradually to avoid plant shock.

Greenhouse Computer Management

• Automate EC adjustments based on light intensity to stabilize root zone conditions.
• Limit EC differences between high and low light conditions to prevent yield loss.

Summer Irrigation Adjustments

• During hot periods, may need night irrigation to prevent excessive dry down and EC rise.
• Monitor moisture content during high temperatures to avoid under-saturation.

Cocopeat Nutrition Management

• Pre-buffering growbags is not necessary if quality cocopeat is sourced.
• Use complete nutrient solutions at hydration to buffer bags.
• Ensure trace elements are in chelated form (EDTA preferred) for availability.
• Maintain nutrient tank pH below 5.5 for optimal nutrient accessibility; use Iron DPTA if runoff pH exceeds 5.8.
• Avoid flushing EC-raising situations with water; increase irrigation frequency instead to lower EC effectively.

This quiz covers essential definitions and concepts related to irrigation management using cocopeat. Focus on the techniques for steering crops, understanding vegetative and generative growth, and the implications for crop production. Ideal for learners interested in agriculture and horticulture.