Irrigation Management in Cocopeat

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Questions and Answers

What is the ideal volume of cocopeat per square meter to enable effective irrigation management?

The ideal volume of cocopeat is approximately 8-10 liters per square meter.

Explain the consequences of having less than 8 liters of cocopeat during hot weather.

Less than 8 liters is insufficient, causing the crop to steer towards generative actions.

How does drying of the root zone at night affect crop growth?

Drying the root zone allows for oxygenation and produces plant hormones that steer growth.

What is the significance of knowing the moisture content of the growbag?

Knowing the moisture content is critical to steer the crop and determine irrigation timing. Signup and view all the answers

What drying percentages at night steer crops towards generative and vegetative actions?

A drying of 8-10% steers generative actions, while less than 6% steers vegetative actions. Signup and view all the answers

What are the two methods for measuring moisture content in growbags?

Moisture content can be measured using scales to weigh water changes or electronic meters to measure water content directly. Signup and view all the answers

Why should irrigation start 1-2 hours after sunrise?

Irrigation should start 1-2 hours after sunrise to allow the crop to wake up and begin absorbing water from the growbag. Signup and view all the answers

What is the consequence of applying irrigation too early?

Applying irrigation too early can create excessive root pressure, which may force water into the fruit and cause splitting. Signup and view all the answers

When should the last irrigation of the day occur?

The last irrigation should occur 2-3 hours before sunset to allow the cocoa peat sufficient drying overnight. Signup and view all the answers

What role does drainage (runoff) play in hydroponic media?

Drainage is essential to regulate the electrical conductivity (EC) of the growbag, affecting the osmotic pressure and water absorption by the plant. Signup and view all the answers

What does 'steering the crop' refer to in irrigation management?

It refers to the techniques and tools used by growers to control crop production and growth. Signup and view all the answers

What is the recommended daily percentage of drainage for cocopeat?

Cocopeat requires approximately 30-40% drainage each day to maintain proper EC levels. Signup and view all the answers

How is vegetative growth characterized in plants?

It is characterized by thick stems, upright flowers, strong leaf growth, and poor fruit set. Signup and view all the answers

When should maximum drainage occur during the day?

Maximum drainage should occur at the peak of light during the day, when the plant is absorbing large volumes of water. Signup and view all the answers

What three purposes does irrigation serve for plants?

It provides water for growth, cooling via transpiration, and draining excess salts from the root zone. Signup and view all the answers

How can the average figure for drainage be adjusted throughout the day?

The average drainage figure for the day must be varied at different times to keep the EC of the root zone constant. Signup and view all the answers

How much irrigation is recommended per square meter based on light requirements?

300 mls of irrigation is recommended per square meter for effective growth. Signup and view all the answers

What is false drain in the context of cocopeat irrigation?

False drain occurs when excess water does not penetrate the cocopeat slab and instead runs around its sides. Signup and view all the answers

What is the maximum irrigation volume recommended per square meter to prevent false drain?

The recommended maximum is 300-450 mls per square meter per application. Signup and view all the answers

Why is it important to link irrigation applications to accumulated light levels?

Linking irrigation to light levels ensures that the crops' water needs meet their growth demands. Signup and view all the answers

In irrigation management, what is considered better: shorter frequent irrigations or longer intervals with larger volumes?

Shorter, more frequent irrigations are better for maintaining moisture levels. Signup and view all the answers

What are the potential effects of poor irrigation management on crop growth?

Poor management can push crops into a highly generative mode, decreasing yields. Signup and view all the answers

What adjustments should be made to irrigation timings according to environmental conditions?

Irrigation timings should be adjusted to suit light levels throughout the day. Signup and view all the answers

What is the critical DRAIN percentage needed to keep the EC in balance in the growbag?

Around 50%. Signup and view all the answers

Why should the first 1 or 2 irrigations not cause DRAIN at the start of the day?

Because the growbag will have dried down at night. Signup and view all the answers

What should be done if the DRAIN EC is found to be HIGH?

Implement more frequent irrigations. Signup and view all the answers

What is the consequence of applying low EC or water alone to reduce the EC in the DRAIN?

It can cause the plant to take up excessive water and result in soft fruit. Signup and view all the answers

Why is it important to check WC graphs during hot night periods for growbags?

To ensure that growbags do not dry down too far. Signup and view all the answers

How should the DRAIN EC be adjusted if a change greater than 0.5 dsm is needed?

It should be done gradually over 1-2 days. Signup and view all the answers

What should be the pH level of nutrient tanks to ensure full nutrient availability?

Less than 5.5. Signup and view all the answers

What form should trace elements like Copper be in to ensure their availability in the root zone?

CHELATE form, such as EDTA. Signup and view all the answers

What role does the greenhouse computer play in managing EC levels?

It automatically adjusts the EC of the irrigation based on light intensity. Signup and view all the answers

During intense summer periods, what extra irrigation measure might be required?

Night applications of irrigation may be needed. Signup and view all the answers

What is recommended if runoff water from growbags has a pH greater than 5.8?

Use Iron DPTA in preference to Iron EDTA. Signup and view all the answers

What should be the maximum difference in EC setpoints between HIGH and LOW light conditions?

No more than 0.5 dsm. Signup and view all the answers

What should you never do if the EC is raised in the root zone?

Never flush with water. Signup and view all the answers

Study Notes

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.

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Description

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.