Quality components for agriculture

Environmental problems in agriculture vary from one country to another. Some of them are caused by natural conditions high native heavy metal content, drought, volcanic eruptions, etc., others depend on agricultural practices leaching of nutrients and pesticides etc, and some are related to human influence in other areas air pollution. Furthermore, these causes are often interrelated. Many scientific studies of the prob- lems and their causes have been carried out. In the public debate, however, methods such as those proposed in ‘organic agriculture’ 1 often outweigh the scientific solutions. It seems as if organic agriculture has become a goal in itself, EU Regu- lation 207892 EEC, 1992. In fact, however, many environmental problems found with con- ventional agriculture are also present with organic agriculture. Agricultural production fulfills important needs of human beings, most importantly the produc- tion of essential nutritional products, supplying raw materials for industrial purposes, producing bioenergy, and environmental stewardship. The purpose of this article is to point out the kinds of problems agriculture is facing and to present important quality components of agricul- ture we should be aware of. The quality compo- nents can be integrated into the concept of sustainable agriculture. We discuss the shortcom- ings of organic farming and, finally, presents im- portant future research areas for agriculture. Hopefully, the perspective and vision presented are a sound contribution to the development of future agriculture.

2. Quality components for agriculture

In this section, the major quality components of agriculture are outlined and structured Table 1. The quality components are aimed for character- izing the quality of agricultural production sys- tems in their wholeness and can be used as a checklist of what we should be aware of concern- ing protection of the environment, production of healthy food and the practice of good ethics. The quality components have been classified into six groups. The protection of agricultural soils is essential for maintaining the production potential and ensuring a high quality of agricultural prod- ucts. As agricultural activities affect not only the soil and agroecosystem, the protection of other biospheres, the atmosphere and groundwater must also be taken into consideration. Conserva- tive resource practices are required to achieve a long-lasting of natural resources. The quality of agricultural products is affected by a wide range of production factors and by post-harvest proce- dures. The whole chain of treatments must be taken into consideration. Agricultural manage- ment also affects whether the appearance of land- scape and countryside is attractive. Last but not least, our ethical view of nature determines how we evaluate and treat conditions. Ethics have Table 1 Quality components for agriculture, classified into six groups Protection of agricultural soils Soil erosion and salinization Soil fertility Subsoil compaction Soil pollution Protection of other biospheres, the atmosphere and groundwater Use of pesticides Leaching of plant nutrients Emission of trace gases Conser6ati6e resource practices Use of water resources Circulation of plant nutrients Energy use Biological diversity High quality of agricultural products Nutritiousness Contamination Hygiene Attracti6e landscape and countryside Appearance of the landscape Appearance of the farm Ethics People Livestock Environment 1 In this article the expression ‘organic farming’ means agriculture that exclude synthetic inorganic fertilizers and syn- thetic pesticides on principle. Fig. 1. Integration of quality components into the overall aims of sustainable agriculture. Ethics are added as an independent but all-encompassing factor. therefore been added as an independent but all- encompassing factor. The relative importance of the quality compo- nents varies between countries or areas depending on the environmental and agricultural conditions. The list of quality components includes a wide range of subjects and therefore each of them can only be discussed briefly. A further and logical step is to quantify the quality components. Such quantification has not been done in this article but will be a part of future work. The question to ask is how our agriculture organic or conventional fits to the defined quality components. A basic requirement for human survival is the sustainability of agriculture. The concept of sus- tainable agriculture has been discussed for several decades and has resulted in a certain consensus about four general aims Lowrance et al., 1986; Anonymous, 1989; Allen et al., 1991; Crews et al., 1991; Christen, 1998: sufficient food and fibre production, environmental stewardship, economic viability and social justice. The quality compo- nents presented in this article can be integrated into the concept of sustainable agriculture. In Fig. 1, the main groups of quality components in Table 1 have been placed under two of the overall aims of sustainable agriculture, sufficient food production and environmental stewardship. 2 . 1 . Protection of soils 2 . 1 . 1 . Soil erosion and salinization Water and wind erosion are processes causing large soil losses, leading to a steady decrease of cultivated land, are among the greatest agricul- tural problems in the world Hudson, 1985. As new soil will not be formed from bedrock within the foreseeable future, it is of vital importance and of highest priority to minimize and counter- act the processes of erosion. In addition, saliniza- tion, the accumulation of salts in the surface soils of arid and semiarid regions where annual evapo- ration is greater than leaching, is detrimental to plant growth. Erosion is a transport process of soil particles by water or wind, but it is driven by an interac- tion of socioeconomic and biophysical factors such as increasing population, fragile economics, and poorly designed farm policies, and is speeded up by unfavourable climatic conditions. A system- atic evaluation of human-induced soil degradation made by Oldeman et al. 1991 shows that the loss of topsoil due to water erosion has affected a total of 920 million hectares, of which 3.8 million hectares are extremely degraded. The area af- fected by wind erosion amounts to 452 million hectares, of which 0.9 million hectares are ex- tremely affected, and the area affected by saliniza- tion amounts to 76 million hectares, of which 0.8 million hectares are extremely affected. A rough calculation indicates that the loss of soil nitrogen caused by water erosion is of the same order of magnitude as the use of N fertilizers in the world FAO, 1997. 2 . 1 . 2 . Soil fertility The fertility of soils is a prerequisite for their production potential. In the long run, soil fertility can only be maintained if the output of plant nutrients through harvested products and losses in the form of leaching and gaseous emissions is compensated by an equivalent input. Otherwise, the consequence is a slow and steady depletion of the amount of plant nutrients, as shown, for example, for the highly weathered soils in coun- tries of sub-Saharan Africa Stoorvogel et al., 1993; Smaling et al., 1996; Mugwira and Nya- mangara, 1998. In Swedish arable soils, for in- stance, ca 10 of the soils have a too low content of the plant micronutrient copper for normal plant production Eriksson et al., 1997. As leaching of several plant nutrients from light or acid soils can be of the same magnitude or even higher than through crop removal Wiklander, 1970, the return of harvested plant nutrients is not sufficient to balance the reduction. Thus, recy- cling needs to be supplemented with the addition of nutrients to avoid a gradual reduction in soils with a low adsorbtive capacity and in the long- term also in heavy textured soils. Historically, nutrient exhaustion and soil erosion may have been the principal reasons why agricultural sys- tems have not been sustainable in humid and humid tropical areas Cox and Atkins, 1979. In arid areas, as a consequence of lack of coordina- tion of watershed systems salinization and nutri- ent exhaustion have been the root causes for the lack of sustainability Cox and Atkins, 1979. Under humid climatic conditions, all soils tend towards acidification Russell, 1988. Thus, liming as a measure to maintain or increase the calcium saturation on soil colloids and soil pH values is of central importance, affecting the biological activ- ity, soil structure, availability of plant nutrients, and weathering. 2 . 1 . 3 . Compaction of subsoils The mass of agricultural machinery has in- creased by a factor of 3 – 4 during recent decades and the number of field trafficking events can reach more than 10 per year Horn, 1995. Soil compaction can therefore be considered a growing problem. In contrast to the compaction of the topsoil, subsoil compaction caused by traffic with heavy farm vehicles is so far regarded as irre- versible Ha˚kansson and Reeder, 1994 or only slightly improvable Horn, 1995. Compaction of the subsoil reduces water and air inflow into subsurface layers, followed by a decrease of the root growth down through the soil profile, result- ing in lower yields and reduced nutrient utilization. Traditional tillage to improve subsoil condi- tions through deep plowing or ripping, sometimes combined with ameliorant addition, have often failed to provide a better structure. Massive soil loosening may not result in long-term improve- ment of the structure because the organic carbon content and microbial activity in subsoils are too low for formation of stable aggregates. It seems that stabilization of loosened particles is only possible through a combination of chemical ame- liorants, roots, organic matter and water manage- ment Olsson et al., 1995. 2 . 1 . 4 . Soil pollution There is an on-going accumulation of heavy metals in European agricultural soils through at- mospheric deposition, certain organic wastes and phosphorus fertilizers. For instance, the average atmospheric deposition of cadmium in Sweden amounts to 1.1 g Cd ha − 1 per year, whereas removal through leaching and crops is assessed at 0.7 g Cd ha − 1 per year Andersson, 1992. As soil microorganisms are very sensitive to heavy metal pollution, the accumulation of metals may lead to concentrations in soil that first of all affect the soil microbial biomass resulting in a loss of microbial functions Giller et al., 1998; Johansson et al., 1998. Soil microorganisms are considered as the most suitable rapid indicator for changes in soil quality Visser and Parkinsson, 1992. Although there is an absence of consensus on metal limits for soils McGrath et al., 1994, it is wise to restrict the rate of metal accumulation in arable soil. Other metals conventionally not determined in soil, for example, silver, rhodium, tungsten, etc., need also to be considered in the future. Application of agrochemicals and sewage sludge and atmospheric deposition of organic compounds on soils and crops means a contami- nation with anthropogenic chemicals Jones, 1991; Beck et al., 1995. For example, the content of polynuclear aromatic hydrocarbons in the arable soils of Western Europe has increased 4-fold over the last century Jones et al., 1989, whereas the content of polychlorinated biphenyl reached a maximum during the late 1960s and since then there has been a dramatic reduction to concentra- tions similar to those of the early 1940s Alcock et al., 1993. In addition, veterinary medicines end- ing up in animal wastes and sewage sludge are transferred to soil. Long-term monitoring of organic compounds in soil has shown that a small fraction remained undecomposed Calderbank, 1989. One main rea- son is that organic compounds can be sorbed in microsites within the soil matrix not available for microrganisms Bergstro¨m and Stenstro¨m, 1998. The declining availability of organic compounds to soil microorganisms means a decrease of toxic- ity of organic chemicals with time Alexander, 1995. Still, with respect to the enormous amounts of organic chemicals produced, the protection of soils against pollution is of greatest environmental and public interest. 2 . 2 . Protection of other biospheres, the atmosphere and groundwater 2 . 2 . 1 . Use of pesticides Pesticides are a powerful tool and of great importance for agricultural production. Applied on arable land, they are transported through wind drift to adjacent areas, leached to surface- and groundwater Kreuger, 1998 and are distributed over large areas through volatilization followed by deposition Siebers et al., 1994; Lode et al., 1995. Use of pesticides in agriculture will lead to their occurrence in other environments. To guar- antee minimal negative side-effects in ecosystems other than the soil-plant system, pesticides, whether natural or synthetic, should have no or low toxicity, except for the target organisms. There seems to be a great potential to develop microbially-derived pesticides, which are effective, reliable and have a low environmental risk Mar- rone, 1999. In addition, new application tech- niques, for example precision band spraying Giles and Slaughter, 1997, can reduce the dose, which can be a very effective way to minimize transport and emission but also to avoid a build- up of resistance of target organisms Powles et al., 1997. 2 . 2 . 2 . Leaching of plant nutrients Eutrophication of water bodies through nitrate and phosphorus is caused by inflow of nutrient- rich groundwater, surface water and sewage Owen and Ju¨rgens-Geschwind, 1986; Armstrong and Burt, 1993. In particular, the transfer of nitrate from farming systems to groundwater is a major environmental concern on the agricultural agenda Nitrate Directive, 1991; National Re- search Council, 1993. Thus, the maintenance of a high water quality through good agricultural practices is of highest priority. It seems that in German agriculture an excess of farm manure is the main reason for the nitrate problem Van der Ploeg et al., 1997. The same is true for the Netherlands Spiertz, 1991 and prob- ably also in countries with similar conditions. The application rate of manure often exceeds the need of the crop, which is ultimately caused by an unbalanced ratio between the number of livestock on farms and the number of hectares used for production. Furthermore, the nutrient use effi- ciency of animal wastes is lower than from inor- ganic fertilizers Kirchmann, 1985. Primarily, excessive use of plant nutrients must be avoided, which does not mean that no inten- sive agriculture can be practised. A historical per- spective on nitrogen leaching in Swedish agriculture showed that leaching of nitrogen in the middle of the 19th century was approximately the same as today Hoffmann, 1999. The reasons were i large areas of fallow; ii poor nitrogen utilization by crops pests, insects, unfavourable chemical and physical conditions and iii en- hanced mineralization from newly cultivated land. One solution to the groundwater pollution problem is to outline principles in national agri- cultural policies regarding livestock density. In Sweden, regulations concerning livestock density, storage capacity and spreading of animal wastes came into force in 1995 Lantbruksstyreslen, 1990. Furthermore, low-leaching cropping sys- tems are needed to control nutrient concentra- tions in percolating soil water and to limit total outflows from arable land. In tropical low-input agriculture, however, not primarily nutrient man- agement but erosion control is necessary to im- prove surface waters Lal and Stewart, 1994. 2 . 2 . 3 . Emission of climatic trace gases The agricultural contribution to an increase of climatic trace gases in the atmosphere is through emissions of methane from ruminants and rice wetlands, emissions of nitrous oxides during the process of nitrification and denitrification in soil, and production of carbon dioxide through decom- position of soil organic matter. However, the role of agricultural soils to act as a source or sink for climatic trace gases and the impact of agricultural practices as a key to control emissions has so far only been briefly examined concerning methane and nitrous oxides Mosier et al., 1991; Willison et al., 1995; Hu¨tsch, 1998, whereas carbon se- questration in agricultural soils has gained consid- erable interest due to a global political agreement on emissions of carbon dioxide Kyoto protocol. A wanted aim is to decrease emissions of trace gases from agriculture, and furthermore to use agricultural soils as an effective absorber and sink for these gases. 2 . 3 . Conser6ati6e resource practices 2 . 3 . 1 . Use of water resources Water is one of the basic elements for agricul- ture and a shortage of water decreases plant pro- duction or even makes cultivation impossible. Water shortage is the major reason for desertifica- tion Steen, 1998a. In most arid and semi-arid regions of the world mainly Third World coun- tries, precipitation is too low to produce crops that will provide self-sufficiency for the calculated population of four billion who will be living in these regions within the next 25 years Greenland et al., 1997. Rainfall patterns are characterized by short and intensive downpours followed by long droughts. Under such conditions, methods that make the best use of each rainfall through collection, storage and directing run-off water to agricultural crops are a prerequisite for survival. As every ton of dry plant biomass requires 200 – 500 m 3 of water Marschner, 1995, the use of water in dry areas for production of low-value staple food in the long term is doubtful. Although there is no alternative today, a change is desirable and even necessary: water should preferably be used to support a biomass of high economic value. Low value biomass should be produced where there is plenty of water and high value biomass should consequently increase its role in areas of water scarcity Falkenmark and Lundqvist, 1998; Steen, 1998b. Construction of both small collection units, as well as dams and larger water reservoirs, seems to a prerequisite for agricultural production in these regions. Waster must be pipelined, stored in cisterns and contain- ers or covered smaller dams to be spread with drip irrigation alongside the plant rows with the pipes laying on the ground or laid in the ground Samad et al., 1992; Clemings, 1996. Extensive grazing of dry areas should be abandoned in favour of more stationary feeding systems. 2 . 3 . 2 . Circulation of plant nutrients Animal husbandry and human food consump- tion are accompanied by the production of wastes. It is a challenge to recycle these wastes to arable land in a proper way, both to compensate for the removal of plant nutrients in harvest and to eliminate the risk caused by deposited wastes. However, if large amounts of wastes are applied to soil, this may also cause environmental pollu- tion Juste and Mench, 1992. Intensive livestock farming very often means that feedstuff has to be purchased input to the farm with the consequence of a surplus of animal wastes in relation to the farming area. The imbal- ance between the amount of animal wastes pro- duced and the arable land available for their recirculation results in a highly enriched soil nu- trient concentration Leinweber et al., 1994 and groundwater pollution due to too high application rates on the soil Liebhardt et al., 1979; Evans et al., 1984. This is an environmental hazard and results in wasteful use of plant nutrients Mengel, 1998. As about 80 of the nutrients from fodder end up in animal wastes, a balanced distribution of animal manure on farm areas is the most important step to establish effective circulation of plant nutrients. The presently open plant nutrient cycle between rural and urban areas may become more closed, if plant nutrients of all municipal organic wastes can be used in agricultural production Lammel and Kirchmann, 1995. However, pollution of wastes with heavy metals and a range of organic com- pounds have so far been a main problem Jacobs et al., 1987; Mininni and Santori, 1987; Witter, 1996. Removal of plant nutrients is highest in systems without livestock as no manure is produced on the farm. In systems with livestock, there is nor- mally a recirculation of nutrients through animal wastes but there are also significant losses, first of all of nitrogen, from the waste materials Jarvis, 1993; Bussink and Oenema, 1998. Despite a highly improved recirculation of wastes of agricultural origin, recirculation is not sufficient to maintain soil fertility because of leaching and gaseous emissions of plant nutrients from soil and wastes, removal of nutrients through pet animal wastes, dead pets and removal through dead humans. Thus, cropping systems relying on circulation of wastes of agricultural origin only will result in negative plant nutrient balances. However, an assessment of phosphorus flows in Swedish society indicate that the recycling of P is greater than removal including leaching because both mineral fodder additives containing P end up in animal manure as well as detergents containing P in sewage sludge Kirchmann, 1998. However, soils under pastoral agriculture are an exception and their nitrogen levels can be maintained, if pastures include leguminous crops, which can contribute substantial amounts of N, up to 400 kg ha -1 yr -1 , through biological fixation Ledgard and Steele, 1992. 2 . 3 . 3 . Energy use The energy demand of agricultural production, expressed in relation to the total national energy consumption Stout et al., 1979; Smil, 1992, ranges from 1.8 to 2.8 in developed countries, 5.3 in the Far East and 6.4 in the oil-rich Near East. The energy use for crop production is B 20 of the total energy quantity of the crop, including direct and indirect inputs, and about 80 of the energy in crops is captured solar energy Pimentel, 1992. Jansson and Siman 1978 calculated the approximate energy input as 14.5 GJ ha − 1 in Swedish agriculture and the output through crops as 65 GJ ha − 1 . Feeding reduced the energy in food to 10 GJ ha -1 . Thus, crop production has a positive energy balance, whereas the transformation of crops into animal products results in a net negative energy balance. It is desirable to reduce the demand for energy by increasing the productivity of agriculture and using fuels more efficiently. Analysis of energy flows will help to identify the most energy-de- manding processes on individual farms. Decisions based on such analyses should help to improve the use of energy sources. Biofuels produced in agriculture can reduce the use of fossil fuels to some extent. For example, the agricultural area has to be increased by 25 for biofuels to be able to provide the energy quantity used in agriculture in Sweden Naturva˚rdsverket, 1997. 2 . 3 . 4 . Biological di6ersity Farmland can be divided into two main types: cultivated fields with arable crops and ‘non-culti- vated’ natural or semi-natural land such as range- land, woodland, peat, islets, hedges, ditches and so on that can harbor a great number of different plant and animal species. The main contribution of agriculture to a high diversity of plant and animal species should be through ‘non-cultivated’ but nevertheless managed farm areas such as meadows and pastures providing habitats for spe- cies of flora and fauna and not by introduction of a variety of species mixed with cultivated crops in the field. Indeed, meadows and pastures are com- posed of such high richness in species that Scandi- navian agroecosystems have a greater diversity than forest ecosystems. Grazing or cutting of these areas with no nutrient input is a prerequisite to maintaining the richness of species. In practice, grazing farm animals are of ultimate importance for their conservation. The genetic resources of cultivated crop species seem to be best protected by systematic collection and storage in gene banks, which is also partly true for the genetic resources of livestock. However, the conservation of biodiversity in ecosystems other than agriculture is an impor- tant task for the sustainability of modern agricul- ture Swanson, 1997. Genetic diversity is a well- recognized factor to enhance agricultural produc- tion. 2 . 4 . High quality of agricultural products Genetic and environmental factors affect the quality of crops Nilsson, 1984. Concerning envi- ronmental factors, soils should enable the produc- tion of nutritious crops that do not contain critical levels of toxic metals or environmental pollutants. Cultivation techniques are needed that minimize plant diseases and the presence of un- wanted fungi and insects as well as pesticide residues. These factors are discussed in other sections. Organic wastes and irrigation water used in plant production must not contain disease-carry- ing bacteria and viruses. Handling of agricultural products must ensure that no unwanted sub- stances, either natural or industrial, can pollute the products. The whole production process must be hygienic and clean. As the handling process includes other factors such as storage, transport and industrial refinement, the topic is not dis- cussed in more detail. 2 . 5 . Attracti6e countryside Agriculture has a great effect on the appearance of the countryside as it keeps the landscape ‘open’. Farms should be tidy and fit into the landscape. The appearance of farms gives the product an image. It may be hard to convince consumers of the quality of a product if the aesthetic of the farm does not support it. Each farm should express robustness, care, attractive- ness and environmental adaptation. 2 . 6 . Ethics 2 . 6 . 1 . Human relationships towards nature Human relationships towards nature are ruled by an ethical code, which has varied throughout history and cultural epochs. The ethical code, however, is deeply conditioned by beliefs about ourselves and our relation to nature. Elmore 1996 summarizes four principally different views on our relationship towards nature. 2 . 6 . 1 . 1 . The geocentric 6iew. Precedence of the ecosystem over human interests: the good of the ecosystem is more important than human life and welfare, people are the problem. 2 . 6 . 1 . 2 . The acentric 6iew. Everything is one and part of the same essence with no major distinction between species and things. Coequality of all cre- ation. This was the view of some American Indi- ans, as manifested in pantheism, New Age philosophy, and often seen in science. 2 . 6 . 1 . 3 . The anthropocentric 6iew. People believe that they are above nature and have no higher authority to hold them accountable for their treatment of the ecosystem. 2 . 6 . 1 . 4 . The theocentric 6iew. Theocentrists believe that a higher authority God than people or the ecosystem exists. He has entrusted man the stew- ardship of his creation Genesis 1:26, 1:28; 2:15. Christianity is theocentric, as are other religions based on the Old Testament. According to Christian ethics, human relations towards nature should consist of three parallel roles – respect, utilization and care even though Christian people have not always acted on these beliefs. 2 . 6 . 2 . Agricultural issues Concerning agriculture, three different ethical issues can be distinguished: i the conditions of the people living and working on the farms; ii the livestock husbandry and iii the impact of cultivation on the environment. The circumstances for earning one’s livelihood from agriculture have to be such that working and social conditions as well as benefits are attrac- tive. Humans are obliged to show kindness and respect to livestock as well as being morally re- sponsible for their health and well-being Hansson, 1996; Nilsson, 1996. Humans should treat their environment in such a way that it is sustainable and can continue to give mankind joy, food and other products.

3. The shortcomings of organic farming