Organic agriculture refers to a farming system that enhance\ud soil fertility through maximizing the efficient use of local resources,\ud while foregoing the use of agrochemicals, the use of Genetic Modified Organisms (GMO), as well as that of many synthetic compounds used as food additives. Organic agriculture relies on a\ud number of farming practices based on ecological cycles, and aims\ud at minimizing the environmental impact of the food industry, preserving the long term sustainability of soil and reducing to a minimum the use of non renewable resources. This paper carries out a\ud comparative review of the environmental performances of organic\ud agriculture versus conventional farming, and also discusses the dif-\ud ficulties inherent in this comparison process. The paper first provides an historical background on organic agriculture and briefly\ud reports on some key socioeconomic issues concerning organic farming. It then focuses on how agricultural practices affect soil characteristics: under organic management soil loss is greatly reduced\ud and soil organic matter (SOM) content increases. Soil biochemical\ud and ecological characteristics appear also improved. Furthermore,\ud organically managed soils have a much higher water holding capacity than conventionally managed soils, resulting in much larger\ud yields compared to conventional farming, under conditions of water scarcity. Because of its higher ability to store carbon in the\ud soil, organic agriculture could represent a means to improve CO2\ud abatement if adopted on a large scale. Next, the impact on biodiversity is highlighted: organic farming systems generally harbor\ud a larger floral and faunal biodiversity than conventional systems,\ud although when properly managed also the latter can improve biodiversity. Importantly, the landscape surrounding farmed land also\ud appears to have the potential to enhance biodiversity in agricultural areas. The paper then outlines energy use in different agricultural settings: organic agriculture has higher energy efficiency\ud (input/output) but, on average, exhibits lower yields and hence reduced productivity. Nevertheless, overall, organic agriculture appears to perform better than conventional farming, and provides\ud also other important environmental advantages, such as halting the\ud use of harmful chemicals and their spread in the environment and\ud along the trophic chain, and reducing water use. Looking at the\ud future of organic farming, based on the findings presented in this\ud review, there is clearly a need for more research and investment\ud directed to exploring potential of organic farming for reducing\ud the environmental impact of agricultural practices; however, the\ud implications of reduced productivity for the socioeconomic system\ud should also be considered and suitable agricultural policies should\ud be developed

Soil health, along with water supply, is the most valuable resource for humans, as human life depends on the soil’s generosity. Soil degradation, therefore, poses a threat to food security, as it reduces yield, forces farmers to use more inputs, and may eventually lead to soil abandonment. Unfortunately, the importance of preserving soil health appears to be overlooked by policy makers. In this paper, I first briefly introduce the present situation concerning agricultural production, natural resources, soil degradation, land use and the challenge ahead, to show how these issues are strictly interwoven. Then, I define soil degradation and present a review of its typologies and estimates at a global level. I discuss the importance of preserving soil capital, and its relationship to human civilization and food security. Trends concerning the availability of arable agricultural land, different scenarios, and their limitations, are analyzed and discussed. The possible relation between an increase in a country’s GNP, population and future availability of arable land is also analyzed, using the World Bank’s database. I argue that because of the many sources of uncertainty in the data, and the high risks at stake, a precautionary approach should be adopted when drawing scenarios. The paper ends with a discussion on the key role of preserving soil organic matter, and the need to adopt more sustainable agricultural practices. I also argue that both our relation with nature and natural resources and our lifestyle need to be reconsidered.

In this paper the environmental impact of current agriculture practices is reviewed. Soil loss (along with soil fertility), increasing water demand from agricultural practices and environmental pollution caused by the intensive use of agrochemicals, are among the most pressing issues concerning agriculture sustainability. Biodiversity loss due to land use change and emission of greenhouse gasses from agricultural activities are also causes for concern. A number of alternative agricultural practices are also presented that can help to make agriculture less environmentally damaging by reducing the use of natural resources, limiting inputs and preserving soil fertility and biodiversity. We think that there is room for a different and more ecological agriculture and that research should be implemented in order to better assess the potential and constraints of the different options. However, notwithstanding the great achievements of the “Green Revolution,” the world will need 70 to 100% more food by 2050. So a new challenge lies ahead: how to feed nine billion with less land, water and energy, while at the same time preserving natural resources and soil fertility? Technical advances are important in order to meet the future needs, but addressing key socioeconomic issues, such as the inequality in the access to resources, population growth, and access to education are also a priority if we want to properly deal with sustainability. It may require our society to change some of its paradigms and “values” if we wish to preserve our support system, the soil and its health, for the future generations.

Humanity is facing possibly the greatest challenge in its history. Population is expected to reach 9 billion in 2030. At the same time agricultural land is becoming scarcer and poorer in quality. Furthermore, the environmental impact of intensive agriculture and the effects of climate change are threatening food security in many regions of the globe. Further, shortage of fossil fuels will have dramatic effects on the performance of intensive agriculture. There is an urge to develop more ecological agricultural practices both to meet the need to preserve agroecosystems health and to deal with the reduced availability of “cheap” energy from fossil fuels. This paper reviews a number of studies comparing the performances of conventional and organic agriculture in light of energy use, CO ₂ emission and other environmental issues. Organic agriculture, along with other low input agriculture practices, results in less energy demand compared to intensive agriculture and could represent a means to improve energy savings and CO₂ abatement if adopted on a large scale. At the same time it can provide a number of important environmental and social services, such as preserving and improving soil quality, increasing carbon sink, minimizing water use, preserving biodiversity, halting the use of harmful chemicals, thereby guaranteeing healthy food to consumers. We claim that more work should be done in terms of research and investment to explore the potential of organic farming for reducing environmental impact of agricultural practices. However, in the case of organic agriculture, the implications of a reduced productivity for the socioeconomic system should be considered and suitable agricultural policies worked out.

Organic farming is promoted to reduce environmental impacts of agriculture, but surprisingly little is known about its effects at the farm level, the primary unit of decision making. Here we report the effects of organic farming on species diversity at the field, farm and regional levels by sampling plants, earthworms, spiders and bees in 1470 fields of 205 randomly selected organic and nonorganic farms in twelve European and African regions. Species richness is, on average, 10.5% higher in organic than nonorganic production fields, with highest gains in intensive arable fields (around +45%). Gains to species richness are partly caused by higher organism abundance and are common in plants and bees but intermittent in earthworms and spiders. Average gains are marginal +4.6% at the farm and +3.1% at the regional level, even in intensive arable regions. Additional, targeted measures are therefore needed to fulfil the commitment of organic farming to benefit farmland biodiversity.