Description  

Organic production is an overall system of farm management and food production that combines best environmental and climate action practices, a high level of biodiversity, the preservation of natural resources and the application of high animal welfare standards and high production standards in line with the demand of a growing number of consumers for products produced using natural substances and processes. [2]  

Key descriptors 

• Organic farming systems are production systems which avoid or largely exclude the use of synthetically compounded fertilizers, pesticides, growth regulators and livestock feed additives 3.Unlike the other farming practices, discussed in the other fiches, organic systems do not consist of a single practice, but of a combination of several “elementary” farming practices, which need to be respected together. Organic systems are defined by the REGULATION (EU) 2018/848 [3]. 
• To the maximum extent feasible, organic systems (significantly more frequently than conventional farming according to a recent meta-analysis by Alvarez, 2021 5) rely on crop rotations, multicropping, crop residues retention, no/minimum tillage, animal manures, green manures, off-farm organic wastes and aspects of biological pest control to maintain soil productivity and tilth, to supply plant nutrients and to control insects, weeds and other pests [4].  
• This review compares the impacts of organic and conventional farming systems. The following types of results are included: 

• Results of field experiments designed by researchers, comparing plots under organic and conventional management. 
• Results of field data or farm-scale surveys on organic and conventional systems, designed and managed by farmers. 
• Results of life-cycle assessments, typically considering a cradle-to-farmgate model.  

• Results were grouped into two categories:  

• Organic cropping systems (including all different types of organic systems), excluding results reported specifically on livestock production. 
• Organic livestock systems, reports specific results where livestock production is the focus, including farms with forage/fodder production dedicated to in-farm livestock production and mixed farming systems (co-production of cash crops and forage/fodder/livestock in the same farm). 

• In all reviewed synthesis papers, results are expressed in two different units: 

• per unit of cultivated area (e.g., per ha)  
• per unit of product (e.g., per kg of grain).  

Since organic systems generally result in lower yields than conventional systems, the effects per unit of product may be different to those per unit of area. Consequently, where available, both types of results are reported in the Table 1. 

Impacts per unit of agricultural land 

Impacts per unit of  

product 

Impact 

Metric 

Positive 

Negative 

No effect 

Uncertain 

Positive 

Negative 

No effect 

Uncertain 

Organic cropping systems 

Increase Acidification 

0 

1 (1) 

1 (1) 

1 (1) 

Decrease Air pollutants emissions 

Ammonia emission 

0 

0 

1 (1) 

0 

0 

0 

1 (1) 

0 

Increase Biodiversity 

9 (9) 

1 (1) 

1 (1) 

1 (0) 

Increase Carbon sequestration 

7 (6) 

0 

0 

2 (1) 

Decrease Energy use 

3 (3) 

2 (1) 

2 (1) 

1 (1) 

Decrease Eutrophication 

0 

1 (1) 

2 (2) 

1 (1) 

Decrease GHG emissions 

Aggregated* GHG emissions 

1 (1) 

0 

3 (2) 

1 (1) 

CH4 emission 

1 (1) 

0 

0 

1 (1) 

1 (1) 

0 

0 

1 (1) 

N2O emission 

2 (2) 

0 

0 

1 (1) 

0 

1 (1) 

1 (1) 

1 (1) 

Decrease Nutrient leaching and run-off 

Nitrogen 

2 (2) 

0 

0 

0 

0 

1 (1) 

1 (1) 

0 

Phosphorous 

0 

0 

2 (2) 

0 

Decrease Pests and diseases 

Increase natural enemies of pests 

2 (2) 

0 

0 

0 

Decrease pests per unit of area 

0 

2 (2) 

0 

0 

Improve Soil biological quality 

1 (1) 

0 

0 

1 (0) 

Increase Soil nutrients 

0 

0 

0 

1 (0) 

Increase Crop yield 

Main cash crop yield ** 

0 

9 (9) 

2 (2) 

1 (1) 

Crop yield stability along years 

0 

1 (1) 

2 (2) 

0 

Decrease land use (per unit of product)*** 

0 

3 (3) 

0 

1 (1) 

Organic livestock systems 

Decrease Acidification 

0 

1 (1) 

1 (1) 

1 (1) 

Increase Carbon sequestration 

2 (2) 

0 

1 (1) 

0 

Decrease Energy use 

1 (1) 

0 

2 (1) 

1 (1) 

Decrease Eutrophication 

0 

1 (1) 

1 (1) 

1 (1) 

Decrease GHG emissions 

Aggregated GHG emissions 

1 (1) 

0 

0 

0 

0 

1 (0) 

3 (2) 

1 (1) 

CH4 emission  

1 (1) 

0 

0 

0 

N2O emission 

1 (1) 

0 

0 

0 

Decrease Nutrients loss 

 Nitrogen 

0 

0 

1 (1) 

0 

Decrease land use (per unit of product)*** 

0 

2 (2) 

0 

1 (1) 

IMPACTS 

FACTORS 

Increase biodiversity  

Landscape structure and heterogeneity (ref 28 ),Taxon (ref 20 ),Pest management strategies (ref 2 ),Herbicide application (ref 2 ),Addition of compost (ref 2 ),Diversity of cover crops (ref 2 ),Experiment scale (ref 14 ),Crop field size (ref 1 ),Organism group (ref 16 ),Proportion of arable land in the surrounding landscape (ref 16 ),Crop type (ref 16 ). 

Increase carbon sequestration  

C input (ref 18 ),Soil disturbance (ref 18 ),Fertilisation intensity (ref 5 ),Climate (ref 5 ),External C input (ref 22 ),Clay concentrations in soils (ref 22 ),Mean annual temperature (ref 22 ),Mean annual precipitation (ref 22 ),External C inputs (ref 22 ),Crop rotation (ref 22 ),External N input (ref 22 ),Legume forages (ref 22 ),Plough depth (ref 27 ),Organic input (ref 27 ),Crop residues incorporation (ref 27 ),Land use type (ref 27 ),Region (or certification guidelines) (ref 4 ),Crop type (ref 4 ),Input of organic matter (ref 24 ),Presence of leys in the rotation (ref 24 ) 

Decrease eutrophication  

Quantity and type of fertilizer (ref1) 

Reduction of energy use  

Type of product (ref 12 ),Cropping pattern (ref 12 ),Data sample size (ref 12 ),Production of mineral fertilisers (ref 24 ) 

Decrease of GHG emissions  

Product/area unit (ref 12 ),Per unit of field area: Positive; Per unit of product: Negative. (ref 15 ) 

Decrease nutrient loss  

Fertilisation regime (ref 27 ),Crop diversification strategies (ref 27 ),C/N ratio of fertilisers (ref 27 ),Livestock density (ref 27 ),Nitrogen input (ref 24 ) 

Decrease pests and diseases 

Pests type (ref 25 ),Crop type (ref 25 7 ),Presence of pest management (ref 25 ),Experiment scale (ref 25 ),Study type (ref 7 ) 

Improve soil biological quality  

Fertilisation (ref 29 ),Diversification strategies (ref 29 ),Pesticides use (ref 29 ),Tillage (ref 29 ) 

Increase crop yield  

Fertilisation regime (ref 6 ),Crop diversification strategies (ref 13 ),Multicropping, crop rotations and the use of cover crops reduce the yield gaps of organic farming. (ref 13 ),Nitrogen input (ref 23 ),Water management (ref 23 ),Type of crop (ref 23 ),Soil pH (ref 23 ),Best practices (ref 23 ),Negative effect (ref 1 ),Fertilisation (ref 30 ) 

Keywords 

1) TOPIC: ("organic farm*" OR "organic agriculture" OR "organic system*" OR "organic product*") AND TOPIC: ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis")

2) TOPIC: ((organic near/4 farm*) OR (organic near/4 agric*) OR (organic near/4 produc*) OR (organic near/3 livestock) OR (organic near/3 animal)) AND TOPIC: ("animal*" OR "livestock" OR "ruminant*" OR "small ruminant*" OR "cattle" OR "dairy cattle" OR "dairy" OR "beef cattle" OR "sheep" OR "ewe*" OR "lamb*" OR "swine" OR "pig*" OR "porcine*" OR "goat*" OR "rabbit*" OR "poultry" OR "chicken*" OR "broiler*" OR "turkey*" OR "hen*" OR "horse*" OR "mule*" OR "milk" OR "egg" OR "beef" OR "cheese" OR "meat" OR (animal near/2 protein*) OR "yogurt" OR "bacon" OR "pork") AND TOPIC: ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis")

or 

1) TI_KEY_ABS: ("organic farm*" OR "organic agriculture" OR "organic system*" OR "organic product*") AND TI_KEY_ABS: ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis")

2) TI_KEY_ABS: ((organic near/4 farm*) OR (organic near/4 agric*) OR (organic near/4 produc*) OR (organic near/3 livestock) OR (organic near/3 animal)) AND TI_KEY_ABS: ("animal*" OR "livestock" OR "ruminant*" OR "small ruminant*" OR "cattle" OR "dairy cattle" OR "dairy" OR "beef cattle" OR "sheep" OR "ewe*" OR "lamb*" OR "swine" OR "pig*" OR "porcine*" OR "goat*" OR "rabbit*" OR "poultry" OR "chicken*" OR "broiler*" OR "turkey*" OR "hen*" OR "horse*" OR "mule*" OR "milk" OR "egg" OR "beef" OR "cheese" OR "meat" OR (animal near/2 protein*) OR "yogurt" OR "bacon" OR "pork") AND TI_KEY_ABS: ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis")

Search dates 

No time restrictions 

Databases 

Web of Science and Scopus, run in September 2021 

Selection criteria 

The main criteria that led to the exclusion of a synthesis paper were when the paper: 1) did not deal with terrestrial grasslands or the effects on grasslands could not be disentangled from other land uses; 2) did not deal with grazing management; 3) was either a non-systematic review, a non-quantitative systematic review, or a meta-regression without mean effect sizes; 4) was not written in English. Due to the high number of potentially valid synthesis papers, we applied additional exclusion criteria: [5]) the paper did not include studies conducted in Europe; 6) the paper only reported impacts on grassland or animal production, but any environmental impacts. Synthesis papers that passed the relevance criteria were subject to critical appraisal carried out on a paper-by-paper basis. 

The search returned 1022 synthesis papers potentially relevant for the practice object of our fiche. From the 1022 potentially relevant synthesis papers, 661 were excluded after reading the title and abstract, and 330 after reading the full text according to the above-mentioned criteria. Finally, 31 synthesis papers were selected for grazing. 

Ref. Num 

Authors 

Year 

Title 

Reference 

DOI 

1 

Crowder, DW; Northfield, TD; Gomulkiewicz, R; Snyder, WE. 

2012 

Conserving and promoting evenness: organic farming and fire-based wildland management as case studies. 

Ecology 93: 2001–2007. 

10.1890/12-0110.1 

2 

Garcia-Palacios, P; Gattinger, A; Bracht-Jorgensen, H; Brussaard, L; Carvalho, F; Castro, H; Clement, JC; De Deyn, G; D'Hertefeldt, T; Foulquier, A; Hedlund, K; Lavorel, S; Legay, N; Lori, M; Mader, P; Martinez-Garcia, LB; da Silva, P; Muller, A; Nascimento, E; Reis, F; Symanczik, S; Sousa, J; Milla, R. 

2018 

Crop traits drive soil carbon sequestration under organic farming 

Journal of Applied Ecology 30, 1–10. 

10.1111/1365-2664.13113 

3 

Gattinger A; Muller A; Haeni M; Skinner C; Fliessbach A; Buchmann N; Mäder P; Stolze M; Smith P; El-Hage Scialabba N; Niggli U. 

2012 

Enhanced top soil carbon stocks under organic farming 

PNAS 109 (44), 18226-18231. 

10.1073/pnas.1209429109 

4 

Katayama, N; Bouam, I; Koshida, C; Baba, YG 

2019 

Biodiversity and yield under different land-use types in orchard/vineyard landscapes: A meta-analysis. 

BIOLOGICAL CONSERVATION 229, 125-133 

10.1016/j.biocon.2018.11.020 

5 

Lichtenberg, EM; Kennedy, CM; Kremen, C; Batary, P; Berendse, F; Bommarco, R; Bosque-Perez, NA; Carvalheiro, LG; Snyder, WE; Williams, NM; Winfree, R; Klatt, BK; Astrom, S; Benjamin, F; Brittain, C; Chaplin-Kramer, R; Clough, Y; Danforth, B; Diekotter, T; Eigenbrode, SD; Ekroos, J; Elle, E; Freitas, BM; Fukuda, Y; Gaines-Day, HR; Grab, H; Gratton, C; Holzschuh, A; Isaacs, R; Isaia, M; Jha, S; Jonason, D; Jones, VP; Klein, AM; Krauss, J; Letourneau, DK; Macfadyen, S; Mallinger, RE; Martin, EA; Martinez, E; Memmott, J; Morandin, L; Neame, L; Otieno, M; Park, MG; Pfiffner, L; Pocock, MJO; Ponce, C; Potts, SG; Poveda, K; Ramos, M; Rosenheim, JA; Rundlof, M; Sardinas, H; Saunders, ME; Schon, NL; Sciligo, AR; Sidhu, CS; Steffan-Dewenter, I; Tscharntke, T; Vesely, M; Weisser, WW; Wilson, JK; Crowder, DW. 

2017 

A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes. 

23, 11,  4946-4957. 

10.1111/gcb.13714 

6 

Smith, OM; Cohen, AL; Reganold, JP; Jones, MS; Orpet, RJ; Taylor, JM; Thurman, JH; Cornell, KA; Olsson, RL; Ge, Y; Kennedy, CM; Crowder, DW 

2020 

Landscape context affects the sustainability of organic farming systems 

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 117 6, 2870-2878 

10.1073/pnas.1906909117 

7 

Smith, OM; Cohen, AL; Rieser, CJ; Davis, AG; Taylor, JM; Adesanya, AW; Jones, MS; Meier, AR; Reganold, JP; Orpet, RJ; Northfield, TD; Crowder, DW 

2019 

Organic Farming Provides Reliable Environmental Benefits but Increases Variability in Crop Yields: A Global Meta-Analysis 

FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 3 

10.3389/fsufs.2019.00082 

8 

Tuomisto HL; Hodge ID; Riordana P; Macdonald DW 

2012 

Does organic farming reduce environmental impacts? – A meta-analysis of European research 

Journal of Environmental Management 112, 309-320 

10.1016/j.jenvman.2012.08.018 

9 

Ugarte, CM; Kwon, H; Andrews, SS; Wander, MM. 

2014 

A meta-analysis of soil organic matter response to soil management practices: An approach to evaluate conservation indicators 

Journal of soil and water conservation 69, 422-430 

10.2489/jswc.69.5.422 

10 

Knapp, S; van der Heijden, MGA. 

2018 

A global meta-analysis of yield stability in organic and conservation agriculture. 

NATURE COMMUNICATIONS 9, 3632 

10.1038/s41467-018-05956-1 

11 

Ponisio, LC; M'Gonigle, LK; Mace, KC; Palomino, J; de Valpine, P; Kremen, C 

2015 

Diversification practices reduce organic to conventional yield gap 

Proc. R. Soc. B 282, 20141396 

10.1098/rspb.2014.1396 

12 

Muneret, L; Mitchell, M; Seufert, V; Aviron, S; Djoudi, E; Petillon, J; Plantegenest, M; Thiery, D; Rusch, A. 

2018 

Evidence that organic farming promotes pest control 

Nature Sustainability 1, 361-368 

10.1038/s41893-018-0102-4 

13 

Seufert, V; Ramankutty, N; Foley, JA 

2012 

Comparing the yields of organic and conventional agriculture 

NATURE 485, 229–232. 

10.1038/nature11069 

14 

Wilcox, JC; Barbottin, A; Durant, D; Tichit, M; Makowski, D. 

2013 

Farmland Birds and Arable Farming, a Meta-Analysis. 

Sustainable Agriculture Reviews 13: 35-63. 

10.1007/978-3-319-00915-5_3 

15 

Doring, J; Collins, C; Frisch, M; Kauer, R 

2019 

Organic and Biodynamic Viticulture Affect Biodiversity and Properties of Vine and Wine: A Systematic Quantitative Review 

AMERICAN JOURNAL OF ENOLOGY AND VITICULTURE 70 3, 221-242 

10.5344/ajev.2019.18047 

16 

de Ponti T., Rijk B., van Ittersum M.K. 

2012 

The crop yield gap between organic and conventional agriculture. 

AGRICULTURAL SYSTEMS 108, 1–9 

10.1016/j.agsy.2011.12.004 

17 

Kaschuk, G;  Alberton, O;  Hungria, M. 

2010 

Three decades of soil microbial biomass studies in Brazilian ecosystems: Lessons learned about soil quality and indications for improving sustainability. 

Soil Biology & Biochemistry 42: 1–13. 

10.1016/j.soilbio.2009.08.020 

18 

Montañez, MN; Amarillo-Suárez, A. 

2014 

Impact of organic crops on the diversity of insects: a review of recent research. 

Revista Colombiana de Entomología 40: 131 - 142. 

NA 

19 

Aguilera, E; Lassaletta, L; Gattinger, A; Gimeno, BS. 

2013 

Managing soil carbon for climate change mitigation and adaptation in Mediterranean cropping systems: A meta-analysis 

AGRICULTURE ECOSYSTEMS & ENVIRONMENT 168, 25-36. 

10.1016/j.agee.2013.02.003 

20 

Bengtsson, J; Ahnstrom, J; Weibull, AC. 

2005 

The effects of organic agriculture on biodiversity and abundance: a meta-analysis. 

Journal of Applied Ecology 42: 261-269. 

10.1111/j.1365-2664.2005.01005.x 

21 

Garratt, MPD; Wright, DJ; Leather, SR. 

2011 

The effects of farming system and fertilisers on pests and natural enemies: A synthesis of current research 

AGRICULTURE ECOSYSTEMS & ENVIRONMENT 141, 261-270. 

10.1016/j.agee.2011.03.014 

22 

Kopittke, PM; Dalal RC; Finn D; Menzies NW 

2016 

Global changes in soil stocks of carbon, nitrogen, phosphorus, and sulphur as influenced by long‐term agricultural production. 

Global change biology 23, 2509-2519 

10.1111/gcb.13513 

23 

Lee K.S., Choe Y.C., Park S.H. 

2015 

Measuring the environmental effects of organic farming: A meta-analysis of structural variables in empirical research 

JOURNAL OF ENVIRONMENTAL MANAGEMENT 162, 263-274. 

10.1016/j.jenvman.2015.07.021 

24 

Lesur-Dumoulin, C; Malezieux, E; Ben-Ari, T; Langlais, C; Makowski, D. 

2017 

Lower average yields but similar yield variability in organic versus conventional horticulture. A meta-analysis. 

Agronomy for Sustainable Development 37, 45 

10.1007/s13593-017-0455-5 

25 

Mondelaers, K; Aertsens, J; Van Huylenbroeck, G. 

2009 

A meta-analysis of the differences in environmental impacts between organic and conventional farming 

BRITISH FOOD JOURNAL 111 10, 1098-1119 

10.1108/00070700910992925 

26 

Skinner, C; Gattinger, A; Muller, A; Mader, P; Fliessbach, A; Stolze, M; Ruser, R; Niggli, U. 

2014 

Greenhouse gas fluxes from agricultural soils under organic and non-organic management - A global meta-analysis 

Science of the Total Environment 468–469, 553–563 

10.1016/j.scitotenv.2013.08.098 

27 

Tuck, SL; Winqvist, C; Mota, F; Ahnstrom, J; Turnbull, LA; Bengtsson, J. 

2014 

Land-use intensity and the effects of organic farming on biodiversity: a hierarchical meta-analysis. 

Journal of Applied Ecology 51: 746-755. 

10.1111/1365-2664.12219 

28 

Puissant, J; Villenave, C; Chauvin, C; Plassard, C; Blanchart, E; Trap, J 

2021 

Quantification of the global impact of agricultural practices on soil nematodes: A meta-analysis 

SOIL BIOLOGY & BIOCHEMISTRY, 161, 108383 

10.1016/j.soilbio.2021.108383 

29 

Alvarez, R 

2021 

Comparing Productivity of Organic and Conventional Farming Systems: A Quantitative Review 

ARCHIVES OF AGRONOMY AND SOIL SCIENCE 

10.1080/03650340.2021.1946040 

30 

Clark, M; Tilman, D. 

2017 

Comparative analysis of environmental impacts of agricultural production systems, agricultural input efficiency, and food choice. 

ENVIRONMENTAL RESEARCH LETTERS 12 6 

10.1088/1748-9326/aa6cd5