AIR POLLUTION

SAMAN JAMIL

EFFECTS OF AIR POLLUTION ON AGRICULTURE AND FORESTRY

Introduction

Agricultural crops can be injured when exposed to high concentrations of various air pollutants.injury ranges visible markings on the foliage to reduced growth and

yield to premature death of plant.

AIR POLLUTION

AGRICULTURE

Major Pollutants involved

• Sulphur dioxide•Ozone•Nitrogen dioxide• Flourides

Minor gaseous pollutants

• Hydrogen sulphide• Carbon monoxide• Bromine• Particulate pollutants• Soot particles• pesticides

SULPHUR DIOXIDE

Sulphur dioxide

Source:

combustion of fossil fuels

Symptoms: sulfurdioxide injury

Blotchy white,red,black spots

Pattern of SO2 entrance to leaves

stomata (microscopic openings) Resultant injury is classified as either acute or chronic.

CROPS:SUSCEPTBLE TO SULFURDIOXIDE

ALFALFA BARLEY

Scorching of alfalfa leaves

BUCKWHEAT RADDISH

RESISTANT CROPS:SULFURDIOXIDE

ONIONCABBAGE

POTATO CORN

IMPACT• When the pigments in enough tissue

are damaged or killed, plants can begin to lose their leaves.• Crop output is greatly reduced • Growth can be stunted. This is

especially noticeable in young plants.

Effects

•Die prematurely•Less productive

2) NITROGEN OXIDESNITROGEN DIOXIDENITRIC OXIDE

Sources

• Combustion of fossil fuels • Motor vehicles

Symptoms

• Visible injury symptoms :• chlorosis in angiospermic leaves and

tip burn in conifer needles.Tip burn is common symptom in bracts, sepals and awns

Effects• NO2 mostly affects the leaves and

seedlings. Its effects decrease with increasing age of the plant and tissue. • Older needles are more sensitive to

the gas than young ones.

3) OZONE

Source of ozone

NCLA• National Crop Loss Assessment Network show

that ozone in the environment also has a detrimental effect on crop production.

• crops show significantly less yield when exposed to levels of ozone in the atmosphere.

Symptom• Yellowing, flecking and blotching in

leaves.• premature senescence and early

maturity.

Sensitive species

Effect of ozone on onion

4) FLOURIDE

SOURCE

• Deposited on plant surface• Industrial processes

Flouride injury

Effect• Fluorisis:Animals grazing on pasture close to

brickworks, smelters, and phosphate fertiliser factories, or fed forage gathered from such areas,may develop fluorosis, a condition characterised by damage to the musculoskeletal system including softening of teeth, difficulty in mastication,lameness and painful gait.

fluorisis

Sensitive crop species

peach grape

Resistant speciestobacco wheat

Significance of agriculture and forestry

Sustainable food production

Cropland

• Global availability of cropland has now fallen by 25% over the past

CROP BREEDING

CROP BREEDING

crop-breeding programmes may also tend to select for higher values of stomatal conductance since this will increase rates of CO2 assimilation

Declining food security

• African crop yields could be halved within 40 years if the degradation of cultivated lands were to continue at present rates (UNEP,2000).

• As a result of declining food security, the number of undernourished people in Africa nearly doubled

Issues and lack of current knowledge

The current ambient levels of pollution in several developing countries are causing:• visible injury and losses in

productivity of many species of agricultural crops

impact

Wood growth

Economy

Control• It is therefore crucial that stakeholders (e.g. in

agriculture, forestry,industry and government) are made aware of the potential impacts of air pollution in different regions.

IDENTIFICATION

• Impacts of air pollutants• Monitoring networks must be established to

record• Reliable air pollution transport models need to

be developed to estimate current and future regional

• Suitable methodologies must be developed torelate pollution to impacts, for use in risk assessment by policy-makers.

conclusion