Organic agriculture and ecosystem services

 

Ecosystem Services (ES), such as biological control, pollination, soil formation, nutrient cycling in agriculture are vital for the sustainable supply of food and fibre. The current trends of decline in the ability of agricultural ecosystems to provide ES pose great threat to food security worldwide.
This article discusses the concept of ES and identifies ES associated with agriculture and the economic and ecological benefits of these ES on farmland in general and its linkages with organic agriculture to help alleviate some of the negative impacts of intensive agriculture and ensure food security, citing examples from global studies.

Background
Intensive agriculture that utilises large quantities of inputs in the form of fertilisers, pesticide, labour and capital made it possible to grow enough food to meet the current global needs. However, these practices made agriculture a major driver of land use change (UNEP, 2005), leading to environmental damage and degradation of several ecosystem services (ES). ES related to terrestrial ecosystems include such processes as biological control of pests, weeds and diseases, pollination of crops, prevention of soil erosion, the hydro-geochemical cycle, capture of carbon by plants and by soil, cultural services, etc. They ensure the production of ecosystem goods, such as food, forage and bio-fuels.

These ES provide major inputs to many sectors of the global economy and have been demonstrated to be of very high economic value (US $33 trillion/yr). Yet because most of these services are not traded in economic markets, they carry no ‘price tags’. There is no exchange value in spite of their high use value that could alert society to changes in their supply or deterioration of underlying ecological systems that generate them. However, ES worldwide are being degraded more rapidly than ever before and this degradation poses serious threats to quality of life and therefore to sustainability of economies. The recent Millennium Ecosystem Assessment (MA) pointed to the very high rate of ES loss and the consequences for global stability if that rate continues. The current trends, if continued unabated, threaten to alter radically not only the capabilities to produce food and fibre but also the delivery of ES by agro-eco-systems.

The key challenge is to meet the food demands of a growing population to achieve Millennium Development Goals (MDGs) by 2015 that include the eradication of hunger (UN, 2005) and yet maintain and enhance the productivity of agricultural systems (UN, 1992). As the economic value of the direct and indirect benefits of ES are substantial, there is growing awareness of the importance of the utilisation these services for the long-term sustainability of agro-ecosystems and their ability to provide increased production while maintaining.

The concept of ES
Natural and modified ecosystems support human existence on the planet through various functions and processes known as ES. In recent years, the concept of ES has gained wide acceptance within the international scientific community. It led to the adoption of the ES concept by the United Nations’ sponsored Millennium Ecosystem Assessment (MA) programme. Key recent work has estimated the value of global ecosystem goods and services (Millennium Ecosystem Assessment, 2003), generating increased awareness of their classification, description, economic evaluation and enhancement. ES value has been assessed using a ‘top-down’ approach to be in the range of US $16–54 trillion/yr, with an annual mean of US $33 trillion which was twice the annual global GDP (gross domestic product) of the world at that time. This study provoked meaningful debate about the economic value and the appropriate ways to value ES. In another study, it was estimated that the annual economic and environmental benefits of biodiversity in the world to be about US $3 trillion/yr.

High economic value of ES led to a paradigm shift in ways of thinking about conservation. However, the thinking at that time was concentrated on natural ecosystems and attributed low values to agro-ecosystems. Now there is growing realisation that ES from farmland are of vital importance in sustaining world food production with human population growing to 9 billion by 2050. Because agriculture covers such a significant portion of the globe, evaluating ES from this sector is very important given the damage being done to these vital services by high-input agriculture worldwide. The need is to address the under-estimation of ES in modified ecological systems such as farmland and explore developing concepts, policies and methods of evaluating ES, as well as the ways in which ES in these systems can be maintained and enhanced to sustain human population without damaging human health and the environment.
Researchers and policy makers are using the concept of ES to enhance farm sustainability worldwide. The Millennium Ecosystem Assessment also promotes the adoption of land management practices that maintain agricultural sustainability without compromising yield and profitability. Increasing concerns about intensive agriculture and its detrimental effects have led to the development of sustainable agricultural practices such as organic farming (FAO/WHO, 2001; IFOAM, 2002). Organic agriculture is defined as ‘‘a holistic production management (whose) primary goal is to optimise the health and productivity of interdependent communities of soil, life, plants, animals and people’ (UNCTAD, 2006).

Therefore, it aims to utilise and maintain ES by improving the natural environment, increased water retention, reduced soil erosion and increased agro-biodiversity (UN, 2008). At present, this is practised on 31 million ha worldwide with a global market of US $26.8 billion, which is increasing at 20% per year.
ES associated with agriculture can be classified into four groups (provisioning, supporting, regulating and cultural services). Based on the ES literature and discussion with experts, several ES have been identified in agro-ecosystems.
Provisioning goods and services - These include food and services for human ‘consumption’ ranging from food, forage, bio-fuels and fuel wood to the conservation of species and agro bio-diversity. These goods and services are produced in agricultural landscapes.

Supporting services - These are the services that are required to support the production of other ecosystem goods and services. In this case, they support the production of grain, wool, fruit and vegetables, etc. Key supporting ES associated with agriculture are biological control of pests (natural enemies of insect pests control the pest populations), biological control of diseases and weeds (natural suppression by soil microbes of soil-borne diseases and weed seed removal by predators), pollination (for seed production), nutrient supply (availability of nutrients by soil microbial activity), carbon sequestration (storage of carbon in soils and vegetation), soil formation (soil turnover by earthworms) etc. The global economic value of these ES was estimated to be $100, $80, $100, $90, $135 and $25 billion annually, respectively.

Regulating services - Ecosystems regulate essential ecological processes that maintain temperature and precipitation. Regulating services associated with agriculture regulate fluctuations in water provision and temperature.
Cultural services - Cultural services contribute to the maintenance of human health and well-being by providing recreation, aesthetics and education opportunities. Agriculture is a single largest employer of people worldwide if one takes the whole food chain (production, processing, distribution, retailing, etc.) and contributes on a massive scale to human well-being. Agriculture also provides aesthetic services as some farmers conserve field-boundary vegetation or enhance landscapes by planting hedgerows, shelterbelts or trees. Some farms provide accommodation and recreational activities for family members as well as for national and international visitors. ‘Biodiversity trails’ in agriculture are not common but have had an increasing impact by offering unique landscape that once existed
Visitors can experience a range of species that reside in the different habitats as they walk the trail in plantations, e.g. biodiversity within farm rows. Participation of farms in research and education enhances this cultural service.

ES concept and organic agriculture
Agriculture is both a consumer and a producer of ES (Fig. 1). A number of ES are utilised to produce other ES such as food, which is supported by the maintenance of soil fertility, plant protection, water regulation and many other services. By using the concept of ES, researchers and practitioners aspire to strike a balance between production and consumption of ES in agriculture for long-term farm sustainability.

Sustainable agriculture involves the use of nature’s goods and services while maintaining them for future generations. Organic agriculture is considered to be one of the production systems that aim to achieve sustainability by utilising and maintaining ES. The estimated magnitude (scale 1–5; in the ratings, 1, 3, and 5 represent the lowest, medium, and highest levels of ES, respectively) of several ES is very high in organic agriculture compared with high-input substitution agriculture. It is well established that organic farming delivers more environmental benefits than conventional agriculture does. The economic value of ES in organic fields was found to be $1516/ha/yr, as compared to $670/ha/yr in conventional ones. These values comprised reduced variable (labour, fuel, pesticides) and lower external costs on human health and the environment.

Figure 1
Economic value of ES in organic agriculture was investigated with regard to the role of land management practices in the maintenance and enhancement of ES in agricultural land by quantifying the economic value of ES at the field level based on an experimental approach. The study sites included 29 arable fields, and comprised 14 organic and 15 conventional fields. In this study, an experimental ‘bottom-up’ approach was used to quantify the economic value of ES associated with highly modified arable landscapes. The role of land management practices in the maintenance and enhancement of ES in agricultural land was investigated by quantifying the economic value of ES at the field level under organic and conventional arable systems. This quantification was based on an experimental approach at field level in contrast with earlier global level value transfer methods.

The mean economic value of provisioning services, regulating services, cultural and supporting services indicated that there were significant differences between organic and conventional fields for the economic values of some ES (supporting and regulating services). This study showed that conventional farming practices can severely reduce the level of some of these services in agriculture whereas organic agriculture practices enhance their economic values.
Economic value of a key ES Biological control of insect pests is a key ES crucial to the production of crops. Ninety-nine per cent of the populations of agricultural pests and diseases are controlled by their natural enemies -predators, parasites, and pathogens. It is estimated that 2.5 million tonnes (active ingredients) of pesticides are used worldwide in crop production. Biological control, if properly utilised on farmland can result in annual savings worth billions of dollars and these services can be enhanced using ‘ecological engineering’ principles. There are several examples of successful biological control practices adopted worldwide. In Kenya, the push-pull system has been tested on farms in six districts and has now been released for use by the national extension systems in East Africa. The ‘push-pull’ eco-technologies whereby plant and insect chemistry is used to deter pests (‘push’) and attract (‘pull’) pests’ natural enemies has improved yields to such an extent that milk production has increased and benefits have been community-wide (IAPPS, 2001).

In conclusion, organic agriculture both utilises and maintains ES. It is therefore more sustainable than is conventional agriculture which degrades some ES. Apart from providing ES, organic agriculture is capable of contributing significantly to global food supply. One recent study examined 293 cases from all over the world and compared yields of organic and conventional systems. This study indicated that organic agriculture has potential to contribute significantly to the global food supply. Increasing concerns about food security in least developed and developing countries will require a wide range of sustainable agricultural practices (combining some organic and conventional practices) to fulfill the food demand of a growing population. Organic agriculture offers great potential to develop low cost, low input, locally available eco-technologies to produce food and fibre, without causing damage to human health and the environment (UN, 2008). This type of ecological knowledge can be easily transferred to small-scale farms in least developed and developing countries where the need is much higher due to non-availability of other high input and costly resources.

The current and future challenge is to develop cost effective, low-input eco-technologies, for their rapid implementation and uptake by end-users. This has potential to ensure sustainable food production for the growing human population. There is greater need to dedicate resources for implementation of ES-enhancement strategies by implementing new mechanisms and policies to maintain and enhance agricultural sustainability without compromising yield.
Sri Lankan plantations should also go for organic agriculture and contribute their share in developing a national ecologically sound and economically sustainable agricultural management system in order to reap the multitude of benefits from such systems.

(The writer can be contacted through treecrops@gmail.com)