ABEN 100 - Lesson 5

Microclimate modification

artificial or natural means to alter the immediate environment of a crop/livestock to create a more favorable microclimate for plants or animals

• Temperature

• Humidity

• Wind/Air Velocity

• Radiation

• Light

• Heat Load

• Water/Moisture Balance

microclimate modification factors

Environmental Control Engineering

Encompasses broader strategies for

managing overall environments (e.g.,

greenhouses, climate-controlled bldgs)

Addresses general environmental needs

across larger spaces.

Advanced technologies like HVAC,

automated climate control, and precision

agriculture.

Focuses on long-term solutions.

Microclimate Modification

Deals with climatic features peculiar

to small areas and processes near

the ground.

Aims to modify adverse conditions

near plants for better growth and

yield.

Windbreaks, mulching, agroforestry,

and crop selection.

Short-term adjustments at the farm

level.

• changes in crop rotation and crop cultivars

• changes in soil cultivation and tillage practices

• a shift of sowing dates

• adapted fertilization

• crop protection measures

Short term adjustments at the farm level involve production techniques:

Long-term adaptations

• major structural changes of farm production systems and need careful

agroeconomic planning and realization at societal level

• involve a set of sectors and stakeholders, such as policy, research, water and

land planning.

• changes in land use and landscape structure

• breeding and biotechnology applications

• crop substitution

• changes in the farm production type

Long-term adaptations examples

• controlling of heat load

• controlling of water balance and wind speed

• modification of temperature and solar radiation

Major processes of microclimatic modifications include:

• increasing the amount of water

stored in the root zone

• increasing infiltration

• reducing soil evaporation

• modifying transpiration

Controlling the water balance involves:

wind breaks or shelter belts.

Winds can be controlled by applying

• increasing the surface absorptive

power, reflective power of the

surrounding objects

• exposure through site selection

• increasing the radiant energy by fog

dissipation

• adopting appropriate row direction

Modification of solar radiation

Alteration in sowing time

Mulch Application

Row spacing and orientation

Irrigation management

Planting methods

Tillage

Shelterbelts/windbreaks

Cropping Systems

Protected Cultivation

Major techniques of field microclimate modifications

Alteration in sowing time

Matching the phenology of the crop to the duration of favorable environmental conditions by selecting the most appropriate sowing time to avoid the periods of stress is crucial for obtaining maximum yields under changing climate

Mulch

layer of material applied at the soil surface, which

leads to conserve soil moisture, moderate soil thermal

regime, reduce weed growth and improve fertility and soil

health.

Mulch,

• materials laid on a soil surface - free from trash

• anchored using the weight of the soil on the edges

• tightly laid to ensure good heat transfer and to prevent

flapping and movement in the wind

• often used with drip irrigation

Mulching

has potential to enhance soil quality over the long-term as well as increase in production.

water vapor barrier

Crop residues placed on the soil surface shade the

soil, serve as a ___ against evaporation losses, slow surface runoff, and increase infiltration.

• Increase soil temperatures (degree varies with mulch type)

• Reduce levels of weeds

• Reduce contact with soil and decay organisms

• Conserve soil moisture (less evaporation)

benefits of mulching

• Plastic must be removed and disposed of

• Greater initial costs

• An increased level of management is required

disadvantages of mulching

Clear

Black

Organic

types of mulch

bark mulch, straw, wood chips, etc.

examples of organic mulching

• rapid heating

• increases soil temperature (6-10oC)

• moisture conservation

• weed growth

• rapid heat loss (no heat

trapping)

Advantages and disadvantages of clear mulching

• no weed growth

• inexpensive

• moisture conservation

• limited heating of soil

(some transfer of heat with

contact with soil)

Advantages and disadvantages of black mulching

• soil cooling & moisture conservation

• organic matter

• slow to warm

• may harbor rodents

Advantages and disadvantages of organic mulching

Narrow row spacing

can create a microenvironment with higher humidity and reduced wind movement between plants; radiation interception by the crop increases and its transmission towards soil surface decreases, which decreases the soil temperature.

Wider spacing

may enhance air circulation, radiation interception by the crop decreases, more radiation falls on

the soil surface and increases the soil temperature.

north to south

Rows oriented ___ can optimize sunlight exposure for crops throughout the day.

Drip Irrigation:

Provides targeted water delivery to the root zone, minimizing water use and reducing humidity around the plant.

Surface Irrigation:

Can influence humidity and temperature depending on the method used and the amount of water applied.

Bed sowing

produced significantly taller plants with greater biomass

and grain yields probably due to better nutrient availability, good soil conditions and weed control in beds.

Intercropping:

Growing different crops together can modify

microclimate by altering humidity, temperature, and light conditions.

Cover Crops:

Planting ___ between main crops can affect soil

temperature, moisture, and nutrient levels.

Tillage

modify the crop microclimate by affecting the soil

properties.

Tillage

increase the porosity and decreases the thermal conductivity of the soil and increases the soil temperature.

Conservation Tillage:

Reduces soil disturbance, minimizing evaporation and maintaining soil structure, which can affect microclimate conditions.

Conventional Tillage:

Tilalge that can impact soil temperature, moisture, and wind speed.

Shelterbelts /Windbreaks

Due to reduction in wind speed, they decrease the

evapotranspiration and increase the temperature and

moisture.

Windbreaks

Can influence the microclimate by reducing wind erosion and providing a more sheltered environment.

shelterbelts

These are belts/ blocks consisting of several rows of trees established at right angles to the prevailing wind.

windbreaks

are strips of trees and/or shrubs planted to protect fields, homes, canals or other areas from wind and blowing soil or sand.

Intercropping, double cropping and other mixed cropping

practices that lead to enhanced

efficiency of farm resources with sustainable crop production

Intercropping

increases the radiation interception by the canopy and decreases its transmission towards the soil surface, thus also decreasing the soil temperature.

Crop Rotation

Varying crops in a sequence can affect microclimate conditions and influence pest and disease dynamics.

Agroforestry

Integrating trees with crops can modify light conditions and provide additional microclimatic benefits.

Protected cultivation

The use of netting and other type of covering has been shown to restrict air movement

around the growing seedlings in higher temperature

Greenhouses and High Tunnels:

Provide controlled environments, influencing temperature, humidity, and light for optimal crop growth.

Shade Structures:

Modify light intensity and temperature in outdoor cultivation.

mini tunnels

placement of plastic or spunbonded fabric sheets on

metal hoops over the developing crop, resulting in a

mini-greenhouse effect

plastic is usually clear and may be solid or perforated

often used in conjunction with plastic mulches and

drip irrigation

• Increased daytime air temperatures

• Covers can protect crops from insect pests

• Spun-bonded fabric will allow passage of rain

and irrigation

• High daytime temperatures may impact

flower development and plant survival

• Labor intensive to install

• May require a lot of labor to ventilate

• Can form a barrier to pollinating insects &/or

precipitation (solid plastic)

mini tunnels advantages and disadvatnages

shade nets/screens

are materials designed to provide shade and control the

amount of sunlight reaching plants, crops, or other objects in various environments

shade nets/screens

• made from polyethylene or knitted fabric

• come in various shading percentages (e.g., 30%, 50%, 70%),

allowing growers to choose the level of shading suitable for

their crops or plants

• protect crops from excessive sunlight, reducing the risk of

sunburn and heat stress and help regulate temperatures by

providing shade during hot periods, preventing overheating.

• reduce the energy consumption for cooling the

environment

• reduce crop transpiration resulting in reduced

water consumption for irrigation

• less occurrence of pests, reducing the use of

pesticide

• diffusion of the solar radiation, allowing its

better use by crops.

benefits of shade nets/screens

Heating Systems:

Utilizing heaters or heat

exchangers to raise ambient temperatures.

Cooling Systems:

Using fans, evaporative cooling, or air conditioning to lower

temperatures, especially in warm climates.

Humidification Systems:

Adding moisture to the air in dry environments.

Dehumidification Systems:

Removing excess moisture from the air, crucial in high-humidity regions.

Ventilation

Utilizing windows, louvers, and other openings to allow the exchange of air.

Mechanical Ventilation:

Using fans and ventilation systems to control air movement.

Artificial Lighting:

Implementing supplemental lighting, especially in greenhouses or indoor facilities.

CO2 Enrichment:

Adding supplemental carbon dioxide to enhance photosynthesis in plants.

Filtration Systems:

Removing pollutants, dust, and pathogens from the air.

Biosecurity Measures:

Implementing practices to prevent the spread of diseases among livestock.

Irrigation Systems:

Controlling the delivery of water to crops.

Drainage Systems:

Managing excess water to prevent waterlogging.

Sensor Networks:

Using sensors to monitor environmental conditions.

Automated Control Systems:

Employing technology to regulate various parameters based on real-time data.

Greenhouse Technology

Implementing technologies like shade systems, thermal

screens, and automated climate control in greenhouse environments.

Minimizing stress on livestock by controlling noise levels in agricultural

settings.

Noise Reduction Measures:

heating systems

cooling systems

examples of temperature control

humidification systems

dehumidification systems

examples of humidity regulation

natural ventilation

mechanical ventilation

examples of ventilation

artificial lighting

light spectrum control

examples of lighting systems

CO2 enrichment

examples of carbon dioxide management

filtration systems

biosecurity measures

examples of air quality control

irrigation systems

drainage systems

examples of water management

sensor networks

automated sensor networks

examples of automation and control systems

greenhouse climate control

examples of greenhouse technology

noise reduction measures

examples of sound and noise control