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2. Introduction 3. Conventional vs. Conservation agriculture, an environmental overview
4. Comparative economic of conservation vs. conventional agriculture
5. Current world-wide state of conservation agriculture
6. EU agri-environmental policy and conservation agriculture
7. Conclusions and final comments
8. References
Annex 1: Conservation agriculture modalities
Annex 2: Photographs.
There is an obvious interdependence between agriculture and environment. Indeed, in the European Union 50.5% of the total territory is agricultural and is 27.9% wooded land. In the last decade, the EU Common Agriculture Policy (CAP) has promoted the modernisation of agriculture in Europe. However, this modernisation has been accompanied by damaging effects on the environment. In fact, conventional agriculture, mainly characterised by straw burning and/or removing and intensive tilling, is still generally used in Europe and has consistent negative effects on soil, water and air quality, global climate, biodiversity and landscape.
In Europe, soil degradation due to erosion and compaction processes is probably the most important environmental problem caused by conventional agriculture, seriously affecting nearly 157 million hectares (16% of Europe, nearly 3 times as large as France). Average soil erosion rates year in Europe (17 tons per hectare per year) greatly exceed the average rate of soil formation (1 ton per hectare per year). Most EU countries are affected by this problem to some extent. In the Mediterranean area, soil erosion is very severe, moderately to seriously affecting 50% to 70% of agricultural land. Conventional agriculture intensification (increased mechanisation and ploughing) over the past 50 years has contributed substantially to this trend, increasing the risk of desertification in the most vulnerable areas. The erosion problem has a strong economic impact on the affected agricultural land, and off-site on the surrounding civil public infrastructure. Estimates indicate that the erosion increases agricultural production costs by about 25% each year (53 EUR per hectare). Further, if on-site and off-site costs are combined, the total annual cost of erosion from agriculture can be estimated at about 85.5 EUR per hectare. Water quality is seriously impaired by conventional agriculture. Soil sediment from eroded agricultural land is by far the most important contaminant of surface water. Because conservation agricultural systems greatly reduce soil erosion (>90% for direct sowing/ no-till, > 60% for non-inversion tillage), the adoption of these systems significantly improve surface water quality by reducing sediment. Further, these systems also result in a reduction of about 70% in herbicide runoff, > 85% in oxidised nitrogen, > 65% in soluble phosphate, and about 69% less water runoff than mouldboard ploughing, all of which are a real boon to improving water quality.
Conventional agriculture, (i.e. straw burning and/ or mouldboard ploughing produce extra carbon dioxide (CO2) emissions to the atmosphere and reduce the potential CO2 sink effect of the soil, thereby decreasing the organic matter content of the soil and contributing to global warming. Historically, intensive tillage of agricultural soils has led to substantial losses of soil carbon (C), frequently over 50% in the 20-30 years of cultivation. Conversely, the adoption of conservation agriculture practices, such as direct sowing or non-inversion tillage counteract these effects.
Biodiversity is reduced in conventional agriculture since bare soil for a long period of time does not provide food and shelter for wildlife at critical times. In contrast, high-residue crop production systems have been shown repeatedly to be attractive and valuable for helping several forms of wild life to thrive in agricultural areas (birds, small mammals, reptiles and soil invertebrates especially predators of key pests).
Conservation agriculture refers to several practices which permit the management of soil for agrarian uses, altering its composition, structure and natural biodiversity as little as possible and defending it from erosion and degradation. Conservation agriculture includes direct sowing/ no-tillage, reduced tillage/ minimum tillage, non - or surface- incorporation of crop residues and establishment of cover crops in both annual and perennial crops. Generally, with conservation agriculture the soil is protected from rainfall erosion and water runoff; the soil aggregates, organic matter and fertility level naturally increase, and soil deformation under heavy wheel load is reduced. Furthermore, less contamination of the surface water occurs, the emissions of CO2 to the atmosphere are reduced and the biodiversity consistently increases.
The economics of conservation agricultural techniques is another important factor to be considered. In conventional agriculture, tillage operations require considerably higher inputs in machinery investment and maintenance, fossil combustibles, and labour inputs as compared to conservation agriculture (especially when compared to direct sowing/ no-tillage). For example, in a non-tillage olive crop the estimated fuel saving is about 60 to 80 litres per hectare and in annual crops it is 31.5 litres per hectare. Generally, conservation agriculture reduce the energy consumption and work rate of farming operations in the range of 15%-50% and increase the energetic productivity -i.e. the yield output per energy input- by 25%-100%.
A strong body of scientific and technological research supporting the environmental benefits and agronomic performance of conservation agriculture has been developed world-wide in the past few decades. Furthermore, the widespread adoption of conservation agriculture in the last decade has been consistently increasing in several countries (USA, Canada, Brazil, Argentine, among others) but notably not in Europe. The EU greatly needs to change its agricultural technology from one that destroys its soil (conventional) to one that conserves, and even «regenerates», the soil, water and air resources (conservationist).
The significance of agriculture for the environment in the European Union is illustrated by the fact that of the total territory of the EU 50.5% is agricultural and 27.9% is wooded land. Indeed, there is a significant interdependence between agriculture and environment (24). The Common Agricultural Policy (CAP) has promoted the modernisation of agriculture in Europe. However, this modernisation has been accompanied by damaging effects on the environment (24). Conventional agriculture, still generally used in Europe, has consistently negative effects on the air and the global climate, water (contamination by sediment, nitrates and pesticides), soil (erosion and degradation), landscape, and biodiversity (24). The objective of this report is to briefly outline the important environmental problems caused by conventional agriculture in Europe and to illustrate how they may be overcome through the adoption of the conservation agriculture techniques.
3. Conventional agriculture vs. Conservation agriculture: an environmental overview
Conventional agriculture is generally harmful to the environment. It includes practices such as crop residue burning or deep soil inversion by tilling to control weeds and to prepare the seed bed. As will be indicated later, these techniques considerably increase soil deformation by compaction, erosion and river contamination with sediments, fertilisers and pesticides. In addition, conventional agriculture techniques increase the emission of CO2 into the atmosphere, contributing to global warming and reduce the sustainability of agriculture by lowering soil organic matter and fertility, along with further negative environmental effects (e.g. a decrease in biodiversity).
Conservation agriculture refers to several practices which permit the management of the soil for agrarian uses, altering its composition, structure and natural biodiversity as little as possible and defending it from degradation processes (e.g. soil erosion and compaction). Direct sowing (non-tillage), reduced tillage (minimum tillage), non - or surface- incorporation of crop residues and establishment of cover crops in perennial woody crops (of spontaneous vegetation or by sowing appropriate species) in perennial woody crops or in between successive annual crops, are some of the techniques which constitute conservation agriculture (see Annex 1 for further details). Generally, conservation agriculture includes any practice which reduces, changes or eliminates soil tillage and avoids residues burning to maintain enough surface residue throughout the year. As will be indicated later, the soil is protected from rainfall erosion and water runoff; soil aggregates are stabilised, organic matter and the fertility level naturally increase, and less surface soil compaction occurs. Furthermore, the contamination of surface water and the emissions of CO2 to the atmosphere are reduced, and biodiversity increases.
Soil erosion is a major environmental threat to the sustainability and productive capacity of conventional agriculture world-wide. Indeed, during the last 40 years, nearly one-third of the world´s arable land has been lost to erosion and continues to be lost at a rate of more than 10 million hectares per year (41). In Europe soil erosion is a serious problem in many areas, affecting all countries to some extent (49). About 115 million hectares (12% of the total European land area, over twice the size of France) are suffering from water erosion and 42 million hectares (4% of the total European land area) from wind erosion (39). Around 25 million hectares are seriously threatened by erosion in Western and Central Europe (21). Furthermore, in the Mediterranean area, soil erosion and degradation is even more severe. In this area water erosion can result in the loss of 20 to 40 tons per hectare of soil in a single storm, with more than 100 ton per hectare in extreme events (37). In Spain, over 50% of the agricultural land is classified as having a medium to high risk of erosion (43), and in its Southern region this figure reaches over 70% (19). The average soil erosion rates in Europe (about 17 ton per hectare per year) greatly exceed the average rate of soil formation of about 1 ton per hectare per year (47). Further, soil erosion and degradation in Europe is increasing (6; 21), thereby increasing the risk of desertification in the most vulnerable areas (24). Conventional agricultural intensification (increased mechanisation and ploughing) over the past 50 years has largely contributed to this trend, particularly in Western Europe. Crop yields in eroded soils are lower than those in protected soils because erosion reduces soil fertility and water availability. For example, in some locations crop yield on severely eroded soils were 9% to 34% lower than those on slightly eroded soil (38). Water resources also decrease due to erosion. For example, in light textured soils, which exhibit high water infiltration rates, following conventional cultivation an almost universal result is very fine and smooth seedbed surfaces, which are very susceptible to crusting by rain impact. Consequently infiltration rates decrease, runoff occurs for long periods and the water is lost to groundwater recharge (30). The use of large amounts of fertilisers, pesticides and irrigation help to offset the deleterious effects of erosion but in themselves have the potential to create pollution and health problems, destroy natural habitats, and contribute to high energy consumption and unsustainable agricultural systems. In fact, the effect of erosion is to increase agricultural production costs by about 25% each year (41). In contrast, no tillage/ reduced tillage generally increase soil bulk density (3), aggregates stability and the vertical orientation of pores, resulting in lower compaction and higher soil strength and trafficability under wet conditions as compared to conventional tillage (22, 45). The driving forces for erosion in Europe are mainly cropping systems that leave the soil surface bare during the rainy season and the burning of crop residues. Excessive tillage as well as tilling during low soil-moisture conditions results in the deterioration of soil structure and an increasing susceptibility to erosion (24). During the 1950´s and 1960´s terracing and cropping that followed contour lines, although costly and/ or only partly effective, were recommended to reduce erosion. In the last few decades there have been a large number of scientific reports developing and supporting conservation agriculture techniques: simply not burning the straw, not ploughing/ tilling and leaving the straw over the soil. These practices are very effective (>90-95%) at drastically reducing soil erosion (Fig. 1).
Fig. 1. Efficiency (%) of direct sowing/ no tillage in soil erosion reduction as compared to conventional tillage (ploughing) in several years in Indiana (USA) (46).
Soil quality is largely governed by organic matter content, which is dynamic and responds effectively to changes in soil management. Apart from areas with a heavy surplus of animal manure, the organic matter content of many cultivated soils across Europe is diminishing as a result of modern intensive agriculture (24). For example, the Soil Survey and Land Research Centre of the UK has shown that under conventional tillage from 1980 to 1995 there has been a decrease in the number of sites with a high organic content (>4%) and a concomitant decrease in those with organic carbon content of below 4% (Fig. 2). Similar results have been obtained by others research groups; generally, in about 20 years of intense tillage most agricultural soils lose 50% of soil C (Figure 3) (33). A decline in organic matter content will affect soil structure and stability, water retention properties, buffering capacity, Fig. 2. Topsoil organic carbon content (%) of cultivated soil in England and Wales, 1980 and 1995. Data from the Soil Survey and Land Research Centre, MAFF, UK, 1997 (cited in 24).
Fig. 3. Change of soil organic matter content with years of cultivation (33). biological activity and the retention and exchange of nutrients. It may also in the medium and long term, make the soil more vulnerable to erosion, compaction, acidification, salinisation, nutrient deficiency and drought (24). In contrast, it has been widely reported that when changing from conventional (mouldboard tillage) to conservation agriculture (direct sowing/ no-tillage) the soil increases its organic matter content over time (Fig. 4 a & b) (28; 29).
Fig 4. a) Effect of long term (12 years) soil management regimes (direct drilling/ no till, minimum tillage and conventional tillage) on the soil organic matter content (top 50 cm; Carmona, Southern Spain) (28).
Fig 4. b) Organic matter content at two depths after 18 years of various tillage treatments (no-till, chisel, disc and mouldboard ploughing ) of soil growing corn in Ontanio, Canada (29). Soil water content is often a very important limiting factor in agricultural productivity, particularly under dry land condition. It has been reported by many authors that conservation techniques (direct sowing) increase the water content in the soil profile in comparison with conventional techniques (ploughing/ tilling), particularly in dry years (4). The straw over the soil decreases soil water evaporation, while each tillage operation increases it.
Soil sediments. These are by far the most important contaminants of surface water, affectingaquatic ecosystems by reducing sunlight penetration to aquatic plants and fouling the habitats of fish and other organisms (11). According to this source, other water contaminants in decreasing order are nutrients, pathogens, organic matter, metals and pesticides (11) (Fig. 5).
Fig. 5. Surface water contaminants in decreasing order (11). Important off-site problems are caused by soil sediments transported in the surface water from eroded agricultural land. These include damage to roadways and sewers, basement siltation, drainage disruption, undermining of foundations and pavements, gullying of roads, earth dam failures, siltation of harbours and channels, loss of reservoir storage, disruption of stream ecology and damage to public health, plus increased water treatment costs. In addition, by raising stream beds and burying streamside wetlands, sediment can increase the probability and severity of floods. Indeed, off-site soil erosion economic damage is nearly 40% of the total cost of the erosion (41). Thus, by implementing conservation agriculture the rest of society would also benefit when the off-site effects of erosion are avoided , up to an estimate of 32 EUR per hectare of agricultural land. If off-site and on-site erosion costs are combined, the total cost of erosion from agriculture in USA were estimated at about 85.5 EUR per hectare of crop land annually (41). Conservation tillage systems greatly reduce soil erosion, with reductions of up to 90 percent or more with direct sowing/ no-tillage (46) and over 60% from non-inversion tillage (9) as compared to conventional tillage. Consequently, the adoption of conservation systems significantly improve surface water quality by reducing sediment.
Use of agrichemicals. Nutrients and pesticides from agricultural land become water quality concerns when they move off target to surface water. Nitrates and pesticides reaching surface water may exceed permissible drinking water standards. At high enough concentrations, pesticides can also be harmful to fish, plants, or other aquatic organisms. Ammonium-nitrogen can be toxic to fish and nitrate-nitrogen and phosphate-phosphorus can increase the growth of aquatic plants and algae, leading to an accelerated eutrophication of lakes. The crop surface residues that characterise conservation agriculture help to intercept nutrients and chemicals and keep them in place until they are used by the crop or degrade into harmless components. Indeed, conservation agriculture also reduces runoff, tightly adsorbed chemicals carried in sediment, such as certain pesticides, ammonium-nitrogen, and sediment-bound phosphate (26). For example, in non-inversion tilled soils, herbicide emissions in drainwater discharges have been substantially reduced, as have total oxidised nitrogen (>85%) and soluble phosphate (> 65%) emissions (32). Further, a comprehensive comparison of tillage systems shows that, on average, conservation agriculture (direct sowing/ no-tillage) resulted in 70% less herbicide runoff, 93% less sediments and 69% less water runoff than mouldboard ploughing- a real boon for improving water quality (9; 26). In conservation agriculture, different methods of chemical applications are required, leading in many cases to overall reduced use. For example, fertilisers instead of being broadcast on the soil and tilled under, are placed in a band at a specific distance from the crop seed, or injected directly into the soil, thus minimising the risk that they may be dispersed from the site by rain or wind. Weed control under conservation agriculture may not require a larger quantity of herbicide than conventional tillage. In addition, the shorter-lived non-soil active agricultural chemicals, exhibiting an extremely low ecotoxicology, normally applied to weeds post-emergence, are the most appropriate. Other management methods, such as narrower rows, or cover crops where possible, enhance weed control technology (8).
3.d. CO2 emissions and global warming European annual mean air temperatures have increased by 0.3-0.6 C since 1990, and climate models predict further increases (24). It is well documented that fossil-fuel burning, because of the CO2 emissions, is the dominant driving force in enhancing global warming. Generally, the critical problem is stabilisation of CO2 concentrations. The agriculture sector world-wide accounts for about one fifth of the annual anthropogenic increase in greenhouse forcing, producing about 50 to 75% of anthropogenic methane and nitrous oxide emissions and about 5% of anthropogenic CO2 emissions (12). Deforestation, biomass burning and other land use changes account for an additional 14%. Conventional agriculture is one of the main drivers of climate change. Ploughing or soil inversion is a principal cause of CO2 emission from cropland (35). There is scientific evidence that soil tillage has been a significant component of the increase in atmospheric CO2 which has occurred in the last few decades (35). Historically, intensive tillage of agricultural soils has led to substantial losses of soil C that range from 30% to 50% (20). These CO2 losses are related to soil fracturing which facilitate the movement of CO2 out of the soil and oxygen into it. Conventional agriculture operations (mouldboard ploughing) bury nearly all the residue and leave the soil in a rough, loose, and open condition resulting in maximum CO2 losses and a consistent reduction of the CO2 sink effect of the soil. Further, agricultural intensification is also an important factor influencing the greenhouse gas (CHG) emissions, about 20% of the greenhouse effect is related to agricultural activities (13). All this contributes to global warming. Conversely, under conservation agriculture (direct sowing/ no-tillage) the C soil content increases annually at a rate of 1.0 tonne per hectare or higher (2). The 17 million hectares under the Conservation Reserve Program in the USA (land with a high risk of erosion being placed into permanent/ no-tilled pasture) will counteract around 45% of the CO2 emitted to the atmosphere from the American agriculture (27). In consequence, based on solid research findings, there is strong current opinion in favour of adopting conservation techniques to prevent losses of C soil content and extra CO2 emission to atmosphere from the soil; and, simultaneously, to increase C soil content (35; 40; 42). The less we till, the more carbon we capture, store or sequester to build up organic matter and long-term productivity and, at the same time, the lesser the carbon dioxide that is released into the atmosphere. Soils high in organic matter protect productivity and reduce water pollution by resisting erosion, absorbing and partitioning rainfall, and degrading or immobilising agricultural chemicals, wastes or other pollutants. Calculations suggest that 100% conversion to no-till agriculture in Europe could mitigate all fossil fuel-carbon emissions from agriculture in Europe, this is equivalent to only about 4.1% of total anthropogenic CO2-carbon produced annually in Europe and to 0.8% of global annual anthropogenic CO2-carbon emissions (44).
More wildlife. Conventional agriculture leaves the soil bare for long periods of time. Lack of quality habitat and sparse nesting cover are a problem for many bird species. In contrast, high-residue crop production systems can provide food and shelter for wildlife at critical times. That is why conservation agriculture, which provides a high level of crop residues, is attractive and valuable for helping several forms of wild life (birds, small mammals, reptiles) to thrive in agricultural areas. Several studies have shown that no-till fields have higher densities of birds (and nests) and are used by a greater variety of bird species during the breeding season than tilled fields (5). Indeed, conservation agriculture provides better feeding (micro arthropods, wild plant seeds) for birds over a longer period of time, generally resulting in a more diverse and greater population of birds (48).
Soil fauna. This is comprised of numerous and diverse organisms, from microscopic bacteria numbering up to 3 billion per gram of soil to earthworms up to 20 cm in length and numbering up to 9.5 million per hectare (41). The vast majority are beneficial to plant productivity through their effects on soil formation, nutrient availability and biological control of pest organisms. Conservation agriculture systems permit the development of a more stratified soil structure that supports a greater abundance and diversity of soil organisms such as microorganisms, nematodes, earthworms and microarthropods (36; 50).
4. Comparative economics of conservation vs. conventional agriculture
In conventional agriculture, tillage operations require considerably higher inputs in machinery investment and maintenance, fossil combustibles and labour inputs as compared to conservation agriculture, especially direct sowing/ no-tillage. For example, in no-till olive crops a saving of about 60 to 80 litres of fuel and 3 to 5 hours of labour per hectare annually is estimated as compared to conventional tillage (10). Generally, conservation agriculture reduce the energy consumption of farming operations and increases energy productivity -this is the yield output per energy input- in the range of 15%-50% and 25%-100%, respectively (31). Direct drilling/ no-tillage requires as little as one pass for planting compared to two or more tillage operations plus planting for conventional tillage. Fewer passes save an estimated 97 EUR per hectare on machinery depreciation and maintenance costs (41). That is, about 1950 EUR savings on a 200 hectares farm. Direct sowing/ no-tillage also permits a fuel saving of an average of 31.5 litres per hectare annually compared to conventional tillage systems (41). These savings normally compensate for or exceed the extra costs of conservation tillage (application of herbicides and direct sowing machinery). The annual cost reduction in direct sowing of annual crops compared to conventional tillage ranges between 40 and 60 EUR per hectare in Southern Europe conditions (1). Therefore, in some areas farmers who adopt conservation techniques are strongly motivated by cost-savings. This is clearly the case of geographical regions where crop land is not highly erodible and/ or of countries where agriculture is not subsidised by the government, such as Argentina and Brazil. In other situations, the direct benefit from the adoption of conservation techniques in the form of machinery, fuel and labour costs are intertwined with the conservation ethic and the concept of land stewardship (7).
5. Current world-wide state of conservation agriculture
On a world-wide basis, the diverse modalities of conservation agriculture have grown dramatically in the past 15 years (Fig. 6). With regard to annual crops, they were practised on 1996 in 78 million hectares, and this has continuous to grow. Direct sowing/ non-tillage has advanced in the past ten years from 6 to 47.5 million hectares, world -wide.
Fig. 6. Direct sowing in annual crops world-wide. 1997 (Total=47,5 million hectares). The USA has been the pioneer country and is still today the leader in conservation agriculture (called there conservation tillage with reference only to annual crops) (Fig.7). The strong support of subsequent USA administrations for conservation tillage through the implementation of the Farm Bills of 1985, 1990 and 1996 Farm Bills is worthy of noting. In 1997, in 37% of the 120 million hectares were cultivated using these techniques, maintaining over 30% of the soil covered with stubble whilst conventional tillage (under 15% of residue coverage) diminished by up to 36.5%. There were over 18 million hectares of direct sowing/ no tillage.
Fig. 7. Evolution of conservation agriculture in USA [direct sowing (== ), conservation tillage (___)]. (18) Other pioneer countries in conservation agriculture are Australia, Canada, Brazil and Argentina. It should be pointed out that in the latter two countries, where agriculture is not subsidised by the government, direct drilling has increased from only a few thousand hectares in 1992 to over 12 and 7 million hectares in 1998. Unfortunately, agricultural conservation in Europe is at the moment very little developed (estimated at <1%-2% of its agricultural land), far behind the countries previously mentioned. Currently, France and Spain are the two countries in Europe where these techniques are practised the most, with about 1 and 0.6 million hectares of annual crops under conservation techniques in 1998. However, the validity of these methods has already been demonstrated in most European agricultural situations.
6. EU agri-environmental policy and conservation agriculture
Many relevant EU documents clearly state the environmental problems caused by agriculture and the need to look for solutions. We briefly mention statements from some of them, as follows: 6.a. Agriculture and Environment, Directorate General VI (DGVI), EU Commission (16) «Farmers stand to gain from protecting the environment because it is in their fundamental economic interest to conserve natural resources for the future. It makes more economic sense to take account of nature conservation from the outset than to have to repair damage after it has done- and this may in any case not even be possible». «Environmental protection and nature conservation create extra work and cost for the farmers, but in no other sector can so much be achieved for the environment for so little input. We must no longer take for granted the contribution made to society by farmers through environment measures but must compensate them appropriately».
6.b. Fifth European Commission (EC) Environmental Action Programme (15) Conservation agriculture fully meets the Fifth EC Environmental Action Programme «Towards Sustainability» (15), since it covers one of the five target sectors (agriculture) of the strategy of this Programme and gives solutions to three of the main seven «themes of targets»: climate change, management of water resources and protection of nature and bio-diversity. Also, in the progress report on implementation of this Programme approved on 19th January 1996 one of the conclusions in the Agriculture sector is that «public authorities in Member States together with farmers´ organisations, the pesticides industry and non-government organisations (NGOs) should promote awareness and develop training on extensive methods and sustainable farming technologies; these actions should be supported at EU level».
6.c. Agenda 2000: Common Agricultural Policy vs. Agri-Environmental instruments (25) At this time «Aid for putting into practice Community regulations in environmental matters» are on the way to being implemented. On 15 July 1997 the Commission adopted a package of measures called «Agenda 2000» (25). This is a key strategy document in which the Commission sets out its view on how the European Union should develop its common policies beyond the year 2000. Among its measures, it outlines the future reform of the Common Agricultural Policy. It reflects that in the coming years, a prominent role will be given to agri-environmental instruments to support a sustainable development of rural areas and respond to society's increasing demand for environmental services. The measures aimed at maintaining and enhancing the quality of the environment will be reinforced and extended. With respect to better integrating the environment into the Common Market Organisations, the Commission will make a proposal enabling Member States to make direct payments conditioned to the respect for environmental provisions. Moreover, targeted agri-environmental measures would be reinforced and encouraged through increased budgetary resources and, where necessary, higher co-financing rates.
6.d. COM (98)353 (14) & Kyoto Protocol (34) As stated in the communication COM (98)353 from the Commission, «CO2 is by far the most important greenhouse gas. Emissions of this gas account for approximately 80% of the impact when the gases in the basket are weighed according to their Global Warming Potential (GWP)». Conservation agriculture can help to put into practice the communication COM (98)353 from the Commission for the development of an effective climate change strategy, taking into account the Kyoto Protocol which specifies «that sinks including forests and agricultural soils can count towards meeting the target».
6.e. Europe´s Environment: The Second Assessment (24) This publication devotes considerable attention to agri-environmental problems, and a specific chapter to «Soil Degradation». However, the European Environment Agency clearly recognises that: «soil degradation is a key environmental problem in Europe in which little development of policies or an unfavourable development of the state of the environment have occurred in the past years» (p. 16), and that «soil erosion/ degradation .... remain serious problems in many areas particularly around the Mediterranean». Little progress has been achieved in soil conservation, another area given particular attention in the EPE (Environmental Program for Europe, key recommendations, p. 20). Furthermore, it is stated that «the most obvious progress in reducing pressure on the environment has been made in those areas where an efficient international framework for action has been established. The absence of any such pan-European framework, for example for soil degradation, has delayed progress, even for the assessment of such problems. (p. 7)». Unfortunately, in the referred chapter dedicated to soil degradation no clear open statements were made on the conservation agriculture techniques, which could be the real answer to the problem.
6.f. Directions towards sustainable agriculture 1999) (15, 17) In this very recent document the «approach taken by the Commission to the integration of environment in agriculture in its Agenda 2000 proposals» is mentioned. Indeed, «sustainable agriculture was made an objective of the EU in the Amsterdam treaty». Further, Commissioners of Agriculture and of Environment, jointly, stated that the «.. (E.U) need to redefine the relationship between agriculture and environment to move towards sustainable agriculture ...» . Specific analysis/ comments on environment problems derived from current agricultural practices are made on water quality (nitrates and phosphates), land use and soil (erosion and degradation, «lack of effective erosion control measures in production systems», «burning of crop residues», .....), among many other statements.
7. Conclusions and final comments
Soil erosion and degradation and related environmental problems of agricultural land are very important in Europe. Up to now the Common Agricultural Policy has not really supported sound environment friendly agricultural practices. In the light of present technology, conservation agriculture can efficiently contribute to the solution of environmental problems across Europe's agricultural land base. These problems are basically the erosion and the loss of the production capacity of soils, the pollution of surface water, the emission of CO2 and other greenhouse gases, and the progressive global warming of the atmosphere, and the loss of biodiversity. Furthermore, conservation agricultural techniques can fit into the «continuum» of different farming systems that are appropriate within the EU. However, it should be pointed out that if farming practices are to consistently change from conventional agriculture towards conservation agriculture farmers need to be convinced that a new way of farming (conservation) is needed, which is quite different to the traditional/ conventional one that they have used for decades. For instances, new techniques for weed management and direct sowing need to be learnt and farm equipment has to be adapted and/ or reorganised to correctly implement conservation techniques. Therefore, a tremendous effort at the administrative and technology transfer level is needed. Agenda 2000 must become the turning point for integrating good environmental and agricultural practices into the Common Agricultural Policy, and, although it is not an easy task, this must include implementation of conservation agriculture practices in order for the reform to be effective in meeting both the economic and the environmental need of European agriculture.
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Annex 1. Modalities of conservation agriculture Direct sowing/ direct drilling/ No-tillage: the soil is left undisturbed from harvest to planting except for nutrient injection. Planting or drilling is accomplished in a narrow seedbed or slot created by coulters, row cleaners, disk openers, in-row chisels or roto-tillers. Weed control is accomplished primarily with herbicides with little environmental impact. Cultivation may be used for emergency weed control. This modality is the best option for the environment for annual crops.
Ridge-till.- The soil is left undisturbed from harvest to planting except for nutrient injection. Planting is completed in a seedbed prepared on ridges with sweeps, disk openers, coulters, or row cleaners. Residue is left on the surface between ridges. Weed control is accomplished with herbicides with little environmental impact and/or cultivation. Ridges are rebuilt during cultivation.
Mulch till/ reduce tillage/ minimum tillage.- The soil is disturbed prior to planting. Tillage tools such as chisels, field cultivators, disks, sweeps or blades are used. Weed control is accomplished with herbicides with little environmental impact and/ or cultivation. In the «non-inversion tillage» soil is disturbed (but not inverted) immediately after harvest to partially incorporate crop residues and promote weed seed/ volunteer germination to provide soil cover during the intercrop period; this is chemically destroyed (with herbicides with a minimum environmental impact) and incorporated at sowing, in one pass, with non-inversion drills.
Cover crops.- Sowing of appropriate species, or growing spontaneous vegetation, in between rows of trees, or in the period of time in between successive annual crops, as a measure to prevent soil erosion and to control weeds. Cover crops are generally managed with herbicides with a minimum environmental impact.
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