climate resilient and environmentally sound agriculture - module 4
DESCRIPTION
Part I - Agriculture, food security and ecosystems: current and future challengesModule 4:Agriculture, environment and healthTRANSCRIPT
CLIMATE-RESILIENT AND ENVIRONMENTALLY SOUND
AGRICULTURE OR “CLIMATE-SMART” AGRICULTURE
Information package for government authorities
Introduction to the information package
The future of humankind and the planet relies on human activities becoming more efficient, the food chain being no exception. This online information package was written with the idea of providing an overview of the challenges that the agriculture sector—and to a certain extent the food production chain—faces to feed the world while becoming more efficient. It also explores ways to address these challenges.
Through simplified concepts and relevant resources and examples, we explore the impacts of global change on agriculture, the impacts of agriculture on ecosystems and possible technical and policy considerations that can help building food security under current and future challenges.
The technical and policy considerations explored are meant to contribute towards climate-resilient and environmentally sound or “climate-smart” agriculture—agriculture that increases productivity; enhances resilience to global change; stops ecosystem services deterioration; and produces economic and social benefits.
The information presented here comes from findings, experience and ideas from all over the world, as we believe there are already elements to catalyse change. We also believe this change has to come largely from local communities, for which reason, wherever possible, we provide examples at local levels.
See how to use the information package.
PART IAGRICULTURE, FOOD SECURITY AND ECOSYSTEMS: CURRENT AND FUTURE CHALLENGES
PART IIADDRESSING CHALLENGES
PACKAGE CONTENT
MODULE 4AGRICULTURE, ENVIRONMENT
AND HEALTH
Module objectives and structure
Module 4. Agriculture, environment and health: Objectives and structure
ObjectivesThis module explores the impacts of agriculture on natural resources, human health and ecosystems. We put an emphasis on the deterioration of land productivity, but also highlight how this affects ecosystem services, which also have a bearing on land productivity.
StructureGiven that many factors contribute to the deterioration of land productivity, the module opens with a general introduction on land degradation, after which different processes that contribute to it are briefly covered. The first half of the module presents processes that mainly lead to depletion of land quality, while the second half discusses land degradation due to excesses, in particular pollution, a form of chemical degradation that not only affects production, but also impairs ecosystems and affect human health. We finish by looking at the effects of improper agriculture management on ecosystem services.
CaveatLand degradation processes often do not act individually and affect more than one land component. Specific examples are presented for each major process, often related to impacts on a single land component, but they cannot be taken in isolation.
Degradation of agricultural land• Land degradation impairs the capacity of land to perform ecosystem services and results in loss of productivity, socio-economic problems, food insecurity and migration
• It costs about US$40 billion annually worldwide, without including hidden costs
Land degradation is the reduction in the capacity of the land to perform ecosystem services (including those of agro-ecosystems and urban systems) that support society and development. It includes damage or change to soils, water bodies, vegetation cover and fauna (micro/macro level) through different processes:
• Physical—crusting, compaction, erosion, waterlogging, depletion of groundwater, etc.
• Chemical—acidification, leaching, salinization, pollution, etc.
• Biological—changes in biodiversity, eutrophication, etc.
Land degradation costs about US$40 billion annually worldwide, without considering hidden costs of increased fertilizer use, loss of biodiversity and unique ecosystems. Degraded land is costly to reclaim and, if severely degraded, may no longer be of use.
Ploughing degraded land in Senegal.
Photo: FAO/Seyllou Diallo.
Module 4. Agriculture, environment and health: Introduction to land degradation
Drivers of agricultural land degradation
• Growing demand for food has led to intensification of farming and therefore increased use of fertilizer, pesticide and machinery
• Over-use of inputs is not only wasteful but also damages agricultural products, as well as the environment
A growing demand for food leads to intensification of farming, which if not done through sound practices, may lead to land degradation. In addition to intensification, other factors can contribute to land degradation, including:
• Fragmentation of land and differences in management;
•Lack of knowledge on environmentally sound technologies;
•Reduction of extension services;
•Natural disasters;
•Lack of incentives to practice environmentally sound agriculture.
Over-use of inputs and lack of appropriate land management practices is not only wasteful but also damages agricultural products, as well as the environment and human health. The following slides cover the main types of land degradation.
Driving Force - Pressure - State - Impact - Response (DPSIR) Framework. More…
Module 4. Agriculture, environment and health: Introduction to land degradation
ResponsesDriving forces
ImpactsDirect pressures
State
Land degradation: depleting processes
Module 4. Agriculture, environment and health: Land degradation
Soil erosion
• Soil erosion is one of the most widespread forms of land degradation
• For the farmer soil erosion reduces crop yields and implies more costs for producing food and fibre
Erosion is the washing or blowing away of surface soil. It is one of the most widespread forms of degradation.
When soil vegetation cover is disturbed by cultivation, grazing, burning, or use of heavy machinery, soil becomes vulnerable to erosion. Erosion accelerates when sloping land is ploughed; grass is removed from semiarid land; cattle, sheep and goats are allowed to overgraze; and hillside forests are cut.
Cropland is at the highest risk of erosion, especially if farming systems leave the land bare exposed to wind and water.
For the farmer, soil erosion reduces crop yields and increases the costs of growing food and fibre by reducing the capacity of the soil to hold water and make that water available to plants; washing away plant nutrients and degrading soil structure; reducing water infiltration; and modifying the terrain. See more…
Soil erosion in sloping agricultural land in Tunisia.
Photo: Photolibrary on soil erosion processes.
Module 4. Agriculture, environment and health: Land degradation
Soil erosionExamples
Soil erosion in China
The China Integrated Science survey for soil erosion and ecological security determined that in 2008 China had 3.6 million km2 of eroded soil.
The survey found that almost every valley in every province had soil erosion, with 646 counties experiencing serious soil erosion, of these, 225 were in the Yellow River Basin, 71 in the Hai River basin, 24 in the Huai River Basin. The provinces with more problems were Sichuan, Shanxi, Gansu, Inner Mongolia and Shaanxi.
According to Chinese experts, by 2000 the economic loss from soil erosion was at least CNY200 billion, equivalent to 2.25% of their national GDP.
A section of the Yellow River in China. Each year 1.5 billion tonnes of soil flows into the Yellow River. Sometimes there is so much sediment in the river it looks like chocolate milk. Three quarters of this silt ends up in the Yellow Sea, with the remainder settling on the river bed, causing the level of the river to rise. Source: Facts and details, Yellow River Basin.
Photo: China Digital Times.Module 4. Agriculture, environment and health: Land
degradation
Loss of soil structure: soil compaction
• Soil compaction is another serious environmental problem with consequences for agricultural production
• Soil compaction increases the risk of crop failure, especially under reduced water supply, and increases farming costs
Soil structure degradation—often called soil compaction—is another serious environmental problem caused by conventional agriculture. The immediate consequences of soil compaction are decreased water and fertilizer efficiency and increased soil erosion.
Soil compaction increases the risk of crop failure under reduced water supply and it increases farming costs—it is more expensive to operate when soil is compacted.
Compaction is a subsurface phenomenon that requires soil excavation in order to view and describe it. The two most common visible forms of soil compaction are massiveness (soil aggregates are compressed into large and dense blocks) and platiness (the soil forms plate-like structures, horizontal to the soil surface).
See FAO brochure on soil compaction and the Queensland Government website.
Example of a compacted soil.
Photo: Photolibrary on soil erosion processes.
Module 4. Agriculture, environment and health: Land degradation
Loss of soil structure: soil compaction
ExamplesSoil compaction in Europe
An estimated area of 33 Mha in Europe is affected by land degradation caused by soil compaction.
In the Netherlands, soil compaction is the most widespread kind of physical soil degradation. Due to continuously increasing wheel loads in agriculture, soil compaction is extending to the subsoil, i.e. the soil below the till layer, including the plough layer.
Soil compaction deserves special attention since it is a persistent phenomenon which is hardly alleviated by natural processes.
The natural susceptibility of European soils to compaction.Source: Joint Research Centre, Soil compaction website.
Module 4. Agriculture, environment and health: Land degradation
Waterlogging• Waterlogging is the rise of the water table into the soil root zone and is
considered severe if the water table is found at less than 30 cm depth
• It results primarily from inadequate drainage and over-irrigation and is closely linked to salinization
Waterlogging is the rise of the water table into the soil root zone, where the plant growth is adversely affected by deficiency of oxygen. The critical depth depends on the kind of crop, but waterlogging is commonly defined as light if the water table is at a depth of 3 m for substantial parts of the year, moderate if it is at less than 1.5 m and severe if the water table occurs at less than 30 cm depth.
Waterlogging should be distinguished from naturally occurring poorly drained areas, and also from inundation or flooding.
Waterlogging results primarily from inadequate drainage and over-irrigation and, to a lesser extent, from seepage from canals and ditches. Waterlogging concentrates salts (drawn up from lower down in the soil profile) in the plant rooting zone, and it is, therefore, closely linked to salinization. See more…
Waterlogging causes yellowing of leaves, stunted growth, small roots and poor nodulation in lupins. Source: Managing waterlogging and inundation in crops.
Module 4. Agriculture, environment and health: Land degradation
WaterloggingExamples
Waterlogging in India
Irrigated agriculture, responsible for transforming India from a food deficient to a food surplus country, is under stress due to waterlogging and soil salinization, which have serious socio-economic and environmental implications.
The Central Soil Salinity Research Institute (CSSRI) reports waterlogging and soil salinity increased at an average rate of 3,000 ha per year between 1991 and 2007 in the Tungabhadra command, while a 42% increase was observed in southwest Punjab over a 4-year period (1997–2001).
Source: Agricultural Land Drainage Reclamation of Waterlogged Saline Lands.
Men building a check dam for irrigation in India.
Photo: FAO/Joerg Boethling.
Module 4. Agriculture, environment and health: Land degradation
Salinization• Salinization of agricultural land by irrigation costs about US$11 billion
per year worldwide
• It reduces crop yields and when it is severe, crops stop growing and ultimately land needs to be taken out of production
The accumulation of salts from improper soil and water management is a serious problem worldwide. The global cost of irrigation-induced salinity is estimated to be US$11 billion per year.
Primary salinization occurs naturally in areas where rocks are rich in soluble salts, in the presence of a shallow saline groundwater table, where rainfall is insufficient to leach soluble salts from the soil, or where drainage is restricted.
Secondary salinization occurs when significant amounts of water are provided by irrigation with no adequate provision of drainage for the leaching and removal of salts.
Salt-affected soils reduce both the ability of crops to take up water and the availability of micronutrients. Salts can also be toxic to plants. Salinity can also be considered a form of pollution.
The reclamation of salt-affected land is costly and often difficult.
.
.Salt-affected soil. Source: Management of irrigation-induced salt-affected soils.
Module 4. Agriculture, environment and health: Land degradation
SalinizationExamples
Salinization in Iran
Based on a recent estimate, 34 Mha or nearly 20% of Iran’s surface area is salt-affected. This includes 25.5 Mha of slightly to moderately affected and 8.5 Mha of severely salt-affected soils.
Salt-affected soils are mainly distributed in the central plateau, southern coastal plain, Khuzestan plain and inter-mountain valleys. The salinization of land and water resources have resulted from both naturally-occurring phenomena and anthropogenic activities, but secondary salinization has been the main cause of the spread of salinity.
Source: Advances in the assessment of salinization and status of biosaline agriculture.
Increase in groundwater salinity in Yazd-Ardakan sub-basin in central Iran. Source: An overview of the salinity problem in Iran-Assessment and monitoring technology in Advances in the assessment of salinization and status of biosaline agriculture.
Module 4. Agriculture, environment and health: Land degradation
Environmental impact of livestock
• Livestock is the world’s largest user of land resources
• Grazing land occupies 26% of the earth’s ice‐free land surface
• Rapid expansion has caused overgrazing and land degradation
The livestock sector has expanded rapidly in recent decades and demand for meat and dairy products continues to grow. A predicted increase of 68% by 2030 compared with 2000 is being mainly driven by population and income growth in developing countries (FAO, 2006).
Livestock is the world’s largest user of land resources, with grazing land occupying 26% of the earth’s ice‐free land surface, and 33% of cropland dedicated to the production of feed (FAO, 2009).
The rapid expansion of the sector is a cause of overgrazing and land degradation and an important driver of deforestation. It is also responsible for CH4 and N2O emissions from ruminant digestion and manure management, and is the largest global source of CH4 emissions. However, the carbon footprint of livestock varies considerably among production systems, regions, and commodities, mainly due to variations in the quality of feed and the feed conversion efficiencies of different animal species (FAO, 2010a). More…
Goats and cattle at a watering hole in Shinile Zone, Ethiopia.
Photo: FAO/Giulio Napolitano.
Module 4. Agriculture, environment and health: Land degradation
Depletion of soil productivity
ReflectionsAll the processes mentioned in the preceding pages contribute to the depletion of soil fertility and therefore productivity by reducing organic matter content; affecting soil structure and other physical and biological characteristics; reducing nutrient availability, the capacity of systems to circulate nutrients; and ultimately result in soil quality and productivity decline.
Soil productivity decline is a deterioration of chemical, physical and biological soil properties. It is more common in extensive and low input systems with inappropriate management practices.Which of the previously described processes are present in agriculture in your area?
How do they affect productivity? Have farmers noticed changes in yields?
Can specific causes of degradation be identified? Which are the most important? Physical, chemical, biological?
Which economic and social drivers can be associated with these processes?
How much does land quality depletion cost in your area?
Are farmers and extension services aware of the rate of degradation? What type of awareness campaigns would be useful in your area? Simple methods of evaluation of land quality can be found in the Visual Soil Assessment (VSA) field guides (See the full text here).
Module 4. Agriculture, environment and health: Land degradation
The other side of the coin: land degradation from excesses—
agricultural pollution
Module 4. Agriculture, environment and health: Agricultural pollution
Agricultural pollution
Module 4. Agriculture, environment and health: Agricultural pollution
• Agriculture pollution comes from different activities, it is difficult to control and can cause serious problems to farmers, ecosystems and consumers
Agricultural pollution comes mainly from:
• Excessive application of chemical fertilizers
• Over use and improper storage of pesticides and inappropriate disposal of obsolete pesticides
• Over use of plastic sheeting and inappropriate disposal
• Excessive or inappropriate application of livestock and poultry manure (also emit GHGs).
• The use of wastewater containing chemical and biological contaminants
• Burning of agricultural residues (also emits GHGs)
Pollution from agriculture is difficult to monitor and control and it can cause serious problems to farmers, ecosystems and consumers.
Discarded pesticide cans in Yeliman, Mali.
Photo: FAO/Ivo Balderi.
Pollution from plant nutrients
Module 4. Agriculture, environment and health: Agricultural pollution
• Growing demand for food leads to intensification of farming and therefore increased use of fertilizer
• Over-use of fertilizer is not only wasteful but also damages agricultural products, human health and the environment
Agriculture intensification has resulted in an excessive use of mineral fertilizers, in particular those containing nitrogen (N) and phosphorus (P). Storage of manure in open fields without protection from rain, direct discharge of manure overflow water to a stream, or leaking manure lagoons can also pollute water bodies.
When large amounts of N (as nitrate) and P (as phosphate) enter in water bodies from runoff, percolation or seepage from farmland, they can produce contamination of drinking water, algal or plankton blooms, eutrophication, reduction of oxygen in water (hypoxia) and mortality of fish and molluscs. Excess of nitrates in livestock systems can also affect land and its potential for production.
Excess nitrates are also absorbed by vegetables. Nitrate is converted in the human body into compounds that are harmful to health, especially for children.
A farmer applies fertilizer to his rice field.
Photo: CAAS.
Pollution from plant nutrients
ExamplesEutrophication
Eutrophication is the over-enrichment of water by nutrients such as nitrogen and phosphorus. Phosphorous is mostly responsible for eutrophication of fresh water while nitrogen for that of salt water. The two most acute symptoms of eutrophication are harmful algal blooms and hypoxia (oxygen depletion), which can destroy aquatic life and cause ecological and economic damage.
The rise in eutrophic and hypoxic events (415 sites have been identified worldwide) has been attributed to agricultural intensification, industrial activities, and population growth. These have doubled N and tripled P flows to the environment compared with natural values.
World hypoxic and eutrophic coastal areas. Source: WRI and NutrientNet programme.
Module 4. Agriculture, environment and health: Agricultural pollution
The eutrophication process. Source: Pew Trusts and World Resources Institute (WRI).
Pollution from pesticides
Module 4. Agriculture, environment and health: Agricultural pollution
• Pesticides are important for maintaining crop yields but their over-use is not only wasteful but may also contaminate agricultural produce and harm other species as well as humans
The term pesticide includes all chemicals that are used to kill or control pests. About a thousand active ingredients are used to manufacture the wide array of pesticides available all over world (herbicides, insecticides, fungicides, nematocides, rodenticides, acaricides, molluscides, aphicides, etc.).
Although there are benefits in applying pesticides, incorrect use is now threatening the long-term survival of ecosystems by disrupting predator-prey relationships, encouraging more pests to develop, causing loss of biodiversity, impairing ecosystem services like pollination and increasing pest resistance to specific pesticides.
Pesticides also affect human health, especially if they are not handled and disposed of safely in agricultural operations, or if they are consumed through food containing pesticide residues. See more…
Spraying a rice field with powdered pesticide.
Photo: FAO/Florita Botts.
Pollution from pesticidesExamples
Pesticides in the Rotterdam Convention and the Stockholm Conventions
The Rotterdam Convention on the Prior Infor-med Consent Procedure for certain hazar-dous Chemicals and Pesticides in International Trade (PIC) and the Stockholm Convention on Persistent Organic Pollutants (POPs) are multilateral treaties. The Rotterdam Convention tries to promote shared responsibilities in relation to importation of hazardous chemicals, while the Stockholm Convention aims to eliminate or restrict the production and use of persistent organic pollutants.
The majority of chemicals of concern to these Conventions are pesticides (see PIC’s Annex III and listed POPs).
Persistent Organic Pollutants in Food (animation, click on the image).
Module 4. Agriculture, environment and health: Agricultural pollution
Aldrin and dieldrin (two of the listed pesticides). Source: FAO Photo Galleries, Prevention and disposal of obsolete pesticides.
Pollution from animal manure
Module 4. Agriculture, environment and health: Agricultural pollution
• In many intensive animal production systems the production of manure exceeds demand
• If not managed properly manure can contribute to pollution by affecting the quality of water, soils, air and the health of ecosystems and humans
Since the large scale production of synthetic fertilizers, animal manure is less used for plant nutrition but in some places it is not applied efficiently and in many intensive animal systems production of manure exceeds demand. Manure mismanagement may affect:
• Quality of water bodies (from runoff and leaching of nitrate (NO3) and P into water bodies);
• Air quality (through emissions of ammonia (NH3));
• Soil quality (acidification, accumulation of Cu and Zn);
• Human health (biological contamination, respiratory problems and toxicity from heavy metals).
Manure mismanagement also is an important source of greenhouse gas emissions to the atmosphere. See more…
Methane released from animal manure may total 18 Mt per year. Source: Livestock’s long shadow, FAO.
Pollution from animal manure
ExamplesLarge scale poultry production in the USA, environmental concerns
The PEW Environment group report Big Chicken: pollution and industrial poultry production in America suggests that the waste produced by concentrated poultry operations in the USA raises serious concerns. Poultry operations in Maryland and Delaware alone generate approx. 42 million ft3 of chicken waste annually, which due to the combination of industrial-level production and the diminishing amount of cropland in these two states has resulted in some of the waste (and its nutrients) reaching the Chesapeake Bay.
A pond near a chicken operation in Maryland Eastern shore is covered with algae, a problem in many areas due to the excess of nutrients. Source: The PEW environment group’s report Big Chicken: pollution and industrial poultry production in America. Module 4. Agriculture, environment and health: Agricultural
pollution
Pollution from potentially toxic elements
Module 4. Agriculture, environment and health: Agricultural pollution
• High levels of potentially toxic elements like arsenic, cadmium, chromium, copper, lead, mercury and zinc can be toxic to plants, animals and are damaging to human health—these can be transferred along the food chain and are bioaccumulated
Soil pollution from potentially toxic elements (PTEs) is of particular concern. Many PTEs are essential for animal and plant growth, but at high concentrations or long term exposure they become toxic. They can be transferred from soils to crops and water and, ultimately, affect human health (Hang et al., 2009).
Many soils naturally contain PTEs, but in some areas human inputs, like excessive use of agrochemicals, use of contaminated manures, sewage sludge or wastewater and leaching or deposition from industrial or mining activities, have increased their concentrations.
High levels of PTEs in soils can be toxic to plants and livestock or bioaccumulate in the food chain. The most common PTEs of concern in agriculture are arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg) and zinc (Zn).
The Drax power station in the UK. Coal fired power stations release PTEs such as arsenic, lead and mercury. Nearby fields can accumulate contaminants.
Photo: Kaskus news.
Pollution from potentially toxic elements
Examples
Module 4. Agriculture, environment and health: Agricultural pollution
Urban agriculture and food safety
Urban and peri-urban agriculture is an important contribution to food security in cities. However, researchers have found that urban soils often contain high concentrations of PTEs, including Cd, Pb and Zn.
In Kampala, where three quarters of Ugandan vehicles circulate, food is grown along roadsides. A recent study at 11 agricultural sites around the city showed that in those with heaviest traffic flows, PTE concentrations in soils exceeded accepted safe limits. In addition, leafy vegetables grown near the road at all sites exhibited dangerously high concentrations of lead. Some of the contamination was in the form of a surface film, which could be washed off, but most of the contaminants were found in the leaf tissue.
Source: The New Agriculturalist.
See also: African Urban Harvest.
Urban agriculture along the roadside in Kampala, Uganda (not part of the mentioned study).
Photos: E. and S. Ritchie.
Pollution from burning of plant biomass
Module 4. Agriculture, environment and health: Agricultural pollution
• Burning of crop residues causes air pollution and results in losses of nutrients
• It also results in deterioration of soil physical properties and adversely affects beneficial soil micro-flora and fauna
Burning of crop residues causes air pollution and results in losses of nutrients. It also adversely affects the beneficial soil micro-flora and fauna (CIMMYT).
It is estimated that humans are responsible for about 90% of biomass burning, mainly through the deliberate burning of forest vegetation as well as of pastures and crop residues to promote re-growth and destroy pest habitats.
Air pollution in the form of carbon dioxide, nitrous oxide, ammonia, and particulate matter in the atmosphere affects the local environment and contributes to global climate change.
Burning residues also leads to a substantial waste of precious nutrient resources (especially nitrogen) and organic matter in the soil (FAO).
Burning of residues causes losses of nutrients and organic matter, and contributes to the air pollution and climate change.
Photo: CIMMYT.
Pollution from burning of plant biomass
Examples
Module 4. Agriculture, environment and health: Agricultural pollution
It is reported that 40–80% of the nitrogen (N) in wheat crop residue is lost as ammonia when it is burned in the field. Although residue burning can have a beneficial effect on the N supply to subsequent crops in the short-term, it has negative long-term effects on overall N supply and soil carbon levels.
The ash left on the soil surface after burning crop residues causes an increase in urease activity and may cause N losses from soil and applied fertilizer.
Crop residue, being an organic material, if left on the soil, leads to an improvement in soil structure and fertility, whereas burning residues leads to a corresponding loss in soil fertility. Methods which retain crop residue, such as Conservation Agriculture (CA), protect the soil and improve the growing environment. More…
Soya planted into wheat straw without removing the previous crop residue (permanent soil cover).
Photo: J. Benites.
Pollution from plastic films
Module 4. Agriculture, environment and health: Agricultural pollution
• Plastic films are used to help retain moisture and prevent weeds but they have become widely dispersed in the environment
• They may contain harmful substances
Plastic film is used widely in agriculture as silo bunker covers, silage bags, bale wrap, greenhouse covers, silage covers, row covers, and mulch film, as well as for packaging. In recent years, the use of agricultural plastic film has increased (CWMI).
Plastic film is not easily recyclable or biodegradable. Residues can be transported by wind over long distances. They can affect soil quality, crop growth and even the quality of agricultural produce.
One ingredient of plastics, bisphenol A (BPA), is an estrogen-like compound, which may leech into water posing a health threat (WHO).
Research indicates that small beads, formed by weathering of plastics adsorb and concentrate polychlorinated biphenyls (PCBs) and pesticides, which may be ingested by fish and thus enter the food chain (USEPA).
Planting groundnut under plastic sheeting in Shaanxi Province, China. While effective for soil and water conservation, pollution from agricultural plastic has become a serious problem in China.
Photo: FAO/Florita Botts.
Contaminated water and food safety
Module 4. Agriculture, environment and health: Agricultural pollution
• Inappropriate agricultural practices can have severe impacts on health, which in turn puts an unnecessary strain on public resources, as funding needs to be allocated to medical treatment
The health impacts of contamination arising from agricultural practices include:
• Contamination of water supplies by pesticides and fertilizers (FAO).
• Microbiological contamination of food crops from the use of water contaminated by human wastes or from runoff from grazing areas and stockyards. The most common diseases associated with contamination are cholera, typhoid, ascariasis, amoebiasis, giardiasis, and Escherichia coli infections.
• Contamination of food crops with toxic chemicals, like pesticides and potentially toxic elements.
• Potential for hormonal disruption (endocrine disruptors) derived from additives in animal and fish production.
See also Food safety along the food chain.
A woman drawing water from a well situated a few metres from a deposit containing deteriorating cans of pesticides in Govani, Mali.
Photo: FAO/Ivo Balderi.
Contaminated water and food safety
Examples
Module 4. Agriculture, environment and health: Agricultural pollution
In rural and peri-urban areas of most developing countries, the use of sewage and wastewater for irrigation is a common practice.
Wastewater is often the only source of water for irrigation in these areas. Even in areas where other water sources exist, farmers often prefer wastewater because its high nutrient content reduces or even eliminates the need for expensive chemical fertilizers.
Concern for human health and the environment are the most important constraints in the reuse of wastewater. While the risks do need to be carefully considered, the importance of this practice for the livelihoods of countless smallholders must also be taken into account.
This means, for example, finding affordable ways of monitoring the presence of harmful contaminants in wastewater, such as heavy metals, and looking at farming practices and crops grown to find ways of minimizing risks of infection for farmers and consumers
Source: Reuse of wastewater for agriculture.
See also: Safe use of wastewater, excreta and greywater.
Treated sewage water mixed with underground water for irrigation.
Photo: FAO/Rosetta Messori.
Greenhouse gas emissions
Module 4. Agriculture, environment and health: Agricultural pollution
• Agriculture contributes directly to about 13.5% of global GHG emissions, through different activities
• These activities can be improved and, therefore, emissions reduced
Agriculture directly emits GHGs in the form of:
• CH4 emissions from livestock: ruminants (e.g. cattle, sheep, goats, camels) emit CH4 as a by-product of their digestive processes.
• Losses of N2O from plant nutrient application: while losses of N2O to the atmosphere occur naturally as a result of the soil nitrogen cycle, the application of any form of nitrogen to amend soil can increase the rate of emissions, especially if applied in excess or carelessly.
• CH4 emissions from rice cultivation: produced under anaerobic conditions in rice paddies.
• N2O and CH4 emissions from manure management: from biological breakdown of organic compounds and nitrification and denitrification of nitrogen contained in manure.
• CO2 from crop residue management (also N2O, CH4) and fuel use.
Share of different sectors in global GHG emissions. Source: adapted from IPCC.
Greenhouse gas emissionsExamples
Methane emissions occur as part of the natural digestive process of livestock (enteric fermentation) and manure management, rice cultivation, agricultural soil management and field burning of agricultural residues. See more…
Nitrous oxide emissions are associated with manure management and the application and deposition of manure and fertilizer use for crop production. See more…
Carbon dioxide emissions are related to fossil fuel burning during production of fertilizer, the livestock production process, processing and transportation of refrigerated products, as well as crop residue burning.
Furthermore, livestock are a major driver of the global trends in land-use and land-use change, including deforestation (conversion of forest to pasture and cropland), desertification, as well as the release of carbon from cultivated soils.
See more…
Module 4. Agriculture, environment and health: Agricultural pollution
Livestock are a significant contributor to global greenhouse gas emissions.
Photo: FAO/Alberto Conti.
Status of land in your areaReflections
Land degradation can also occur from the excessive use of inputs or inappropriate management practices. The degradation of water, soil and ecosystems through pollution is of great concern, as it is more difficult to reverse than in the case of soil fertility depletion.
The conservation of resources through a balanced use of inputs and efficient practices should become a priority to be able to continue benefiting from ecosystem services and having resources to meet demands for food, feed and fodder.
A start towards better resource management is to have an idea of the current status of land (including soil, water and biota). Examples of assessments can be found in the website of the Land Degradation Assessment in Drylands (LADA) project, which has developed methodologies for local and national assessments.Is agricultural pollution a concern in your area? If so, how bad is it?
Are soil tests done in your area to determine the amount of nutrients needed for specific crops?
What about manure management? Could practices be contributing to pollution or emission of GHG? Are farmers aware of the consequence of improper use of inputs?
Could there be any health concerns related to pollution caused by agriculture?
Are you aware of the safe practices for handling, storing and disposing of pesticides? Module 4. Agriculture, environment and health: Status of land
in your area
Agriculture and ecosystem services
ReflectionsAs mentioned in module 1, ecosystem services are under pressure from human activities. Agriculture can either contribute to the enhancement of these services or cause them to deteriorate through any of the processes described in this module. These processes can affect the following ecosystems services (these are only a few examples):
• Provisioning services: by affecting water availability an its quality for other uses; missing the benefits of plant species for medicinal purposes if they disappear (as a result of mono-cropping or use of a limited number of species or varieties).
• Regulating services: by interfering with carbon cycles through deforestation, burning of residues and loss of organic matter by soil erosion; promoting the proliferation of pests and diseases due to mono-cropping; interfering with pollination and soil organisms functions due to the excessive use of pesticides; reducing the capacity of ecosystems to cope with droughts.
• Supporting services: Interfering with nutrient dispersal and cycling through excessive release of nitrogen and phosphate (causing eutrophication and hypoxia); reducing biological diversity through the use of only a few species in cultivation.
• Cultural services: by changing landscapes, e.g. deforestation, erosion.
Module 4. Agriculture, environment and health: Agricultural and ecosystem services
The good news is that all these can be avoided by recognising the threats and using more efficient and sound practices. How are agricultural practices affecting ecosystem services in your area?
Resources
Module 4. Agriculture and ecosystems health: Resources
References used in this module and further readingThis list contains the references used in this module. You can access the full text of some of these references through this information package or through their respective websites, by clicking on references, hyperlinks or images. In the case of material for which we cannot include the full text due to special copyrights, we provide a link to its abstract in the Internet.
Institutions dealing with the issues covered in the moduleIn this list you will find resources to identify national and international institutions that might hold information on the topics covered through out this information package.
Glossary, abbreviations and acronymsIn this glossary you can find the most common terms as used in the context of climate change. In addition the FAOTERM portal contains agricultural terms in different languages. Acronyms of institutions and abbreviations used throughout the package are included here.
Module 4. Agriculture and ecosystems health
Please select one of the following to continue:
Part I - Agriculture, food security and ecosystems: current and future challenges
Module 1. An introduction to current and future challenges
Module 2. Climate variability and climate change
Module 3. Impacts of climate change on agro-ecosystems and food production
Module 4. Agriculture, environment and health
Part II - Addressing challenges
Module 5. C-RESAP/climate-smart agriculture: technical considerations and examples of production systems
Module 6. C-RESAP/climate-smart agriculture: supporting tools and policies
About the information package:
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How to cite the information package
C. Licona Manzur and Rhodri P. Thomas (2011). Climate resilient and environmentally sound agriculture or “climate-smart” agriculture: An information package for government authorities. Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences and Food and Agriculture Organization of the United Nations.
