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Data extracted in January 2022
Fiche created in February 2024
Note to the reader: This general fiche summarises all the environmental and climate impacts of COVER AND CATCH CROPS found in a review of 40 synthesis papers[1]. These papers were selected from an initial number of 158 obtained through a systematic literature search strategy, according to the inclusion criteria reported in section 4. The impacts reported here are those for which there is scientific evidence available in published synthesis papers, what does not preclude the farming practice to have other impacts on the environment and climate still not covered by primary studies or by synthesis papers.
The synthesis papers review a number of primary studies ranging from 4 to 269. Therefore, the assessment of impacts relies on a large number of results from the primary studies, obtained mainly in field conditions, or sometimes in lab experiments or from model simulations.
1. DESCRIPTION OF THE FARMING PRACTICE
- Description:
- Cover crops are grown to provide vegetative cover between rows of main crops in orchards and vineyards, or in the period between two main arable crops to prevent erosion and minimize the risk of surface runoff by improving the infiltration. They may also function as catch crops, which scavenge the remaining nitrogen after the main crop is harvested, thereby reducing nutrient losses from leaching. They are temporary crops that may be cut and removed or incorporated into the soil. The practice of incorporating crops into the soil to provide nutrient is defined as “green manuring”[2]
- Spontaneous vegetation left growing with the same purpose of cover crops is also included under this practice
- Key descriptors:
- Crops sown on purpose during the fallow season, or undersown to winter/spring main crops, or sown between rows of tree or vineyard crops as mean of soil living cover.
- Spontaneous vegetation left growing with the objective of covering the soil.
- Mono- or multi-species cover/catch crops including legumes (N-fixing species), non-legumes (grass or broadleafs) or mixtures.
- Permanent/annual intercropping in orchards, i.e. refers to the maintenance of a permanent cover crop in the alleys, such as aromatics, while annual intercropping means the presence of cover crops in the alleys that are annually harvested or incorporated into the soil.
- Cover/catch crops are terminated before the main cash crop is harvested, by different strategies: Mechanical, tillage with direct incorporation to soil or herbicide termination.
- Cover/catch crops biomass, after termination, can be either:
- left on soil as mulch or green manure.
- incorporated as green manure.
- harvested and exported from the field.
- Catch/cover crops or spontaneous living soil cover are compared to bare soil during fallow season (e.g. winter) or to uncovered soil/active removal of spontaneous vegetation by tillage.
- NA
2. EFFECTS OF THE FARMING PRACTICE ON CLIMATE AND ENVIRONMENTAL IMPACTS
(table 1)
The table below shows the number of synthesis papers with statistical tests reporting i) a significant difference between the Intervention and the Comparator, that is to say, a significant statistical effect, which can be positive or negative; or ii) a non-statistically significant difference between the Intervention and the Comparator. In addition, we include, if any, the number of synthesis papers reporting relevant results but without statistical test of the effects. Details on the quality assessment of the synthesis papers can be found in the methodology section of this WIKI.
Out of the 40 selected synthesis papers, 32 included studies conducted in Europe, and 39 have a quality score higher than 50%.
Table 1: Summary of effects. Number of synthesis papers reporting positive, negative or non-statistically significant effects on environmental and climate impacts. The number of synthesis papers reporting relevant results but without statistical test of the effects are also provided. When not all the synthesis papers reporting an effect are of high quality, the number of synthesis papers with a quality score of at least 50% is indicated in parentheses. Some synthesis papers may report effects for more than one impact, or more than one effect for the same impact.
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| Statistically tested | Non-statistically tested | ||
Impact | Metric | Intervention | Comparator | Significantly positive | Significantly negative | Non-significant | |
Increase Biodiversity | biodiversity | Cover crops | Bare soil | 1 | 0 | 0 | 0 |
Increase Carbon sequestration | SOC | Cover crops | Bare soil | 9 | 0 | 4 | 1 |
Legume cover crops | Bare soil | 3 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 2 | 0 | 0 | 0 | ||
Increase GHG emissions | CH4 emission | Cover crops | Bare soil | 0 | 1 | 0 | 0 |
Increase GHG emissions | N2O emission | Cover crops | Bare soil | 2 | 4 | 4 | 0 |
Decrease GHG emissions | N2O emission | Legume cover crops | Bare soil | 0 | 2 | 0 | 0 |
Non-legume cover crops | Bare soil | 1 | 1 | 2 | 0 | ||
Decrease Nutrient leaching and run-off | N loss | Cover crops | Bare soil | 6 | 0 | 2 | 0 |
Legume cover crops | Bare soil | 2 | 0 | 5 | 0 | ||
Non-legume cover crops | Bare soil | 7 | 0 | 0 | 0 | ||
Decrease Nutrient leaching and run-off | P loss | Cover crops | Bare soil | 1 | 0 | 0 | 0 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Decrease Pests and diseases | Natural enemies | Cover crops | Bare soil | 0 | 0 | 1 | 0 |
Decrease Pests and diseases | Pests | Cover crops | Bare soil | 2 | 0 | 2 | 0 |
Decrease Pests and diseases | Weeds | Cover crops | Bare soil | 5 | 0 | 2 | 0 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Increase Plant nutrient uptake | Nutrient use efficiency | Legume cover crops | Bare soil | 1 | 0 | 0 | 0 |
Non-legume cover crops | Bare soil | 0 | 0 | 1 | 0 | ||
Increase Pollination | Pollination | Cover crops | Bare soil | 0 | 0 | 0 | 1 |
Increase Soil biological quality | Soil biological quality | Cover crops | Bare soil | 7 | 0 | 2 | 0 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 1 | 0 | 1 | 0 | ||
Decrease Soil erosion | Soil erosion | Cover crops | Bare soil | 4 | 0 | 1 | 1 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Increase Soil nutrients | Soil nutrients | Cover crops | Bare soil | 4 | 0 | 4 (3) | 0 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Increase Soil physico-chemical quality | Soil physico-chemical quality | Cover crops | Bare soil | 3 | 0 | 0 | 1 |
Increase Soil water retention | Soil water retention | Cover crops | Bare soil | 2 | 3 | 3 | 1 |
Legume cover crops | Bare soil | 1 | 0 | 0 | 0 | ||
Non-legume cover crops | Bare soil | 0 | 0 | 1 | 0 | ||
Increase Water use | Water use efficiency | Cover crops | Bare soil | 1 | 0 | 0 | 0 |
Increase Crop yield | Cash crop yield | Cover crops | Bare soil | 5 | 1 | 8 | 1 |
Legume cover crops | Bare soil | 7 | 1 | 2 | 0 | ||
Non-legume cover crops | Bare soil | 0 | 3 | 7 | 0 |
3. FACTORS INFLUENCING THE EFFECTS ON CLIMATE AND ENVIRONMENTAL IMPACTS
The factors significantly influencing the size and/or direction of the effects on the impacts, according to the synthesis papers included in this review, are reported below. Details about the factors can be found in the summaries of the meta-analyses available in this WIKI.
Table 2: List of factors reported to significantly affect the size and/or direction of the effects on environmental and climate impacts, according to the synthesis papers reviewed. The reference number of the synthesis papers where those factors are explored is given in parentheses.
Impact | Factors |
Carbon sequestration | Cash crop (Ref11), Climatic conditions (Ref16), Cover crop biomass production (Ref4), Cover crop residue management (Ref22), Cover crop type (Ref22), Crop residue retention (Ref16), Growing window (Ref4), No factor reported (Ref24), Pedo-climatic zone (Ref4), Rotation type (Ref4), Soil depth (Ref11, Ref16), Soil pH (Ref16), Soil texture (Ref4, Ref11), Tillage (Ref4) and Time scale (Ref16) |
GHG emissions | Cover crop residue management (Ref22), Cover crop type (Ref22), N fertilisation rate (Ref33, Ref38), Period (Ref33) and Period of Nitrous Oxide Measurement (Ref38) |
Nutrient leaching and run-off | Cover crop biomass production (Ref28), Cover crop species (Ref28), Mean annual precipitation (Ref3, Ref28), Mean annual temperature (Ref3), N cover crop input to soil (Ref40), No factor reported (Ref38), Planting dates (Ref28), Slope gradient (Ref3) and Soil texture (Ref28) |
Pests and diseases | Cash crop seeding time (Ref23), Cover crop biomass production (Ref14, Ref23), Herbicides use (Ref23), No factor reported (Ref24), Seeding rate (Ref23), Sowing season (Ref23), Ternination period (Ref23), Tillage management (Ref23), Time after cover crop (Ref14) and Type of weed (Ref14) |
Soil biological quality | Annual precipitation (Ref5), Climate (Ref12), Fertilizer rate (Ref12), No factor reported (Ref24), Soil P content (Ref19), Soil pH (Ref5), Soil texture (Ref5), Soil type (Ref12), Termination method (Ref5) and Termination type (Ref12) |
Soil erosion | Slope gradient (Ref3) and Vegetation coverage (Ref3) |
Soil nutrients | Cover crop residue management (Ref22), Cover crop type (Ref22) and Duration (Ref35) |
Soil physico-chemical quality | Associated practices (Ref17), Soil depth (Ref30), Soil texture (Ref17) and Years of treatment (Ref17) |
Soil water retention | Cover crop biomass production (Ref7), Pedo-climatic zone (Ref7), Soil depth (Ref30), Soil type (Ref7) and Termination method (Ref7) |
Water use | Cover crop biomass production (Ref7), Pedo-climatic zone (Ref7), Soil type (Ref7) and Termination method (Ref7) |
Crop yield | Cash crop seeding time (Ref7), Climate (Ref40), Climate zone (Ref2), Cover crop biomass production (Ref7), Cover crop phenology (Ref40), Fruit tree age (Ref2), Mineral fertilisation rate (Ref40), N fertilisation rate (Ref37), Nitrogen fertilisation rates (Ref34), No factor reported (Ref24), Pedo-climatic zone (Ref7), Soil P content (Ref19), Soil type (Ref7, Ref25, Ref37, Ref40), Termination of cover crop before main crop (Ref34), Termination type (Ref25) and Tillage (Ref40) |
4. SYSTEMATIC REVIEW SEARCH STRATEGY
Table 3: Systematic review search strategy - methodology and search parameters.
Parameter | Details |
Keywords | WOS: TS= ("cover* crop*" OR "catch* crop*" OR "winter cover*" OR "soil cover*") AND TS= ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis") |
Time reference | No time restriction. |
Databases | Web of Science and Scopus: run on 01 January 2022 |
Exclusion criteria | The main criteria that led to the exclusion of a synthesis paper are: |
5. SYNTHESIS PAPERS INCLUDED IN THE REVIEW
Table 4: List of synthesis papers included in this review. More details can be found in the summaries of the meta-analyses.
Ref Num | Author(s) | Year | Title | Journal | DOI |
Ref1 | Crystal-Ornelas, R; Thapa, R; Tully, KL | 2021 | Soil organic carbon is affected by organic amendments, conservation tillage, and cover cropping in organic farming systems: A meta-analysis | Agriculture, Ecosystems & Environment 312, 107356 | 10.1016/j.agee.2021.107356 |
Ref2 | Fang, LF; Shi, XJ; Zhang, Y; Yang, YH; Zhang, XL; Wang, XZ; Zhang, YT | 2021 | The effects of ground cover management on fruit yield and quality: a meta-analysis | ARCHIVES OF AGRONOMY AND SOIL SCIENCE | 10.1080/03650340.2021.1937607 |
Ref3 | Liu, R; Thomas, B; Shi, XJ; Zhang, XL; Wang, ZC; Zhang, YT | 2021 | Effects of ground cover management on improving water and soil conservation in tree crop systems: A meta-analysis | CATENA 199, 105085 | 10.1016/j.catena.2020.105085 |
Ref4 | McClelland, SC; Paustian, K; Schipanski, ME | 2021 | Management of cover crops in temperate climates influences soil organic carbon stocks: a meta-analysis | Ecological applications, 31, 3, e02278 | 10.1002/eap.2278 |
Ref5 | Muhammad, I; Wang, J; Sainju, UM; Zhang, SH; Zhao, FZ; Khan, A | 2021 | Cover cropping enhances soil microbial biomass and affects microbial community structure: A meta-analysis | Geoderma 381, 114696 | 10.1016/j.geoderma.2020.114696 |
Ref6 | 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 |
Ref7 | Wang, J; Zhang, SH; Sainju, UM; Ghimire, R; Zhao, FZ | 2021 | A meta-analysis on cover crop impact on soil water storage, succeeding crop yield, and water-use efficiency | Agricultural Water Management, 256, 107085 | 10.1016/j.agwat.2021.107085 |
Ref8 | Bai, XL; Zhang, ZB; Cui, JJ; Liu, ZJ; Chen, ZJ; Zhou, JB | 2020 | Strategies to mitigate nitrate leaching in vegetable production in China: a meta-analysis | Environmental Science and Pollution Research 27, 18382–18391 | 10.1007/s11356-020-08322-1 |
Ref9 | Chen J., Xiao H., Li Z., Liu C., Ning K., Tang C. | 2020 | How effective are soil and water conservation measures (SWCMs) in reducing soil and water losses in the red soil hilly region of China? A meta-analysis of field plot data | Science of The Total Environment 735, 139517 | 10.1016/j.scitotenv.2020.139517 |
Ref10 | Jian, Jinshi; Lester, Brandon J.; Du, Xuan; Reiter, Mark S.; Stewart, Ryan D. | 2020 | A calculator to quantify cover crop effects on soil health and productivity | Soil and Tillage Research 199, 104575 | 10.1016/j.still.2020.104575 |
Ref11 | Jian, Jinshi; Du, Xuan; Reiter, Mark S.; Stewart, Ryan D. | 2020 | A meta-analysis of global cropland soil carbon changes due to cover cropping | Soil Biol. Biochem. 143, 107735 | 10.1016/j.soilbio.2020.107735 |
Ref12 | Kim, N; Zabaloy, MC; Guan, KY; Villamil, MB | 2020 | Do cover crops benefit soil microbiome? A meta-analysis of current research | SOIL BIOLOGY & BIOCHEMISTRY, 142, 107701. | 10.1016/j.soilbio.2019.107701 |
Ref13 | Morugan-Coronado, A; Linares, C; Gomez-Lopez, MD; Faz, A; Zornoza, R | 2020 | The impact of intercropping, tillage and fertilizer type on soil and crop yield in fruit orchards under Mediterranean conditions: A meta-analysis of field studies | Agric. Syst. 178, 102736 | 10.1016/j.agsy.2019.102736 |
Ref14 | Nicholas, V; Martinez-Feria, R; Weisberger, D; Carlson, S; Basso, B; Basche, A | 2020 | Cover crops and weed suppression in the US Midwest: A meta-analysis and modeling study | AGR ENV LETT 2020;5, e20022 | 10.1002/ael2.20022 |
Ref15 | Payen FT, Sykes A, Aitkenhead M, Alexander P, Moran D, MacLeod M. | 2020 | Soil organic carbon sequestration rates in vineyard agroecosystems under different soil management practices: A meta-analysis | J. Clean. Prod. Elsevier 125736 | 10.1016/j.jclepro.2020.125736 |
Ref16 | Bai, XX; Huang, YW; Ren, W; Coyne, M; Jacinthe, PA; Tao, B; Hui, DF; Yang, J; Matocha, C | 2019 | Responses of soil carbon sequestration to climate-smart agriculture practices: A meta-analysis | Global Change Biology, 25, 2591-2606 | 10.1111/gcb.14658 |
Ref17 | Basche, AD; DeLonge, MS | 2019 | Comparing infiltration rates in soils managed with conventional and alternative farming methods: A meta-analysis | PloS one, 14 (9): e0215702. | 10.1371/journal.pone.0215702 |
Ref18 | Gu, JX; Nie, HH; Guo, HJ; Xu, HH; Gunnathorn, T | 2019 | Nitrous oxide emissions from fruit orchards: A review | Atmospheric Environment 201, 166-172 | 10.1016/j.atmosenv.2018.12.046 |
Ref19 | Hallama, M; Pekrun, C; Lambers, H; Kandeler, E | 2019 | Hidden miners - the roles of cover crops and soil microorganisms in phosphorus cycling through agroecosystems |
| 10.1007/s11104-018-3810-7 |
Ref20 | Lee, H; Lautenbach, S; Nieto, APG; Bondeau, A; Cramer, W; Geijzendorffer, IR | 2019 | The impact of conservation farming practices on Mediterranean agro-ecosystem services provisioning-a meta-analysis | REG ENVIRON CHANGE | 10.1007/s10113-018-1447-y |
Ref21 | Meyer, N; Bergez, JE; Constantin, J; Justes, E | 2019 | Cover crops reduce water drainage in temperate climates: A meta-analysis | Agronomy for Sustainable Development 39, 3 | 10.1007/s13593-018-0546-y |
Ref22 | Muhammad, I., Sainju, U.M., Zhao, F., (...), Fu, X., Wang, J. | 2019 | Regulation of soil CO2 and N2O emissions by cover crops: A meta-analysis | Soil and Tillage Research 192, pp. 103-112 | 10.1016/j.still.2019.04.020 |
Ref23 | Osipitan OA, Dille JA, Assefa Y, Radicetti E, Ayeni A, Knezevic SZ | 2019 | Impact of cover crop management on level of weed suppression: A meta-analysis | Crop Science 59, 3, 833-842 | 10.2135/cropsci2018.09.0589 |
Ref24 | Shackelford, GE; Kelsey, R; Dicks, LV | 2019 | Effects of cover crops on multiple ecosystem services: Ten meta-analyses of data from arable farmland in California and the Mediterranean | LAND USE POLICY, 88, 104204. | 10.1016/j.landusepol.2019.104204 |
Ref25 | Toler, HD; Auge, RM; Benelli, V; Allen, FL; Ashworth, AJ | 2019 | Global Meta-Analysis of Cotton Yield and Weed Suppression from Cover Crops | Crop science 59, 3, 1248-1261 | 10.2135/cropsci2018.10.0603 |
Ref26 | Mahal, NK; Castellano, MJ; Miguez, FE | 2018 | Conservation Agriculture Practices Increase Potentially Mineralizable Nitrogen: A Meta-Analysis | SOIL SCI SOC AM J, 82, 1270–1278 | 10.2136/sssaj2017.07.0245 |
Ref27 | Osipitan, OA; Dille, JA; Assefa, Y; Knezevic, SZ | 2018 | Cover Crop for Early Season Weed Suppression in Crops: Systematic Review and Meta-Analysis | Agronomy Journal 110, 6, 2211-2221 | 10.2134/agronj2017.12.0752 |
Ref28 | Thapa R, Mirsky SB, Tully KL | 2018 | Cover Crops Reduce Nitrate Leaching in Agroecosystems:A Global Meta-Analysis | Journal of Environmental Quality 47, 6, 1400-1411 | 10.2134/jeq2018.03.0107 |
Ref29 | Winter, S; Bauer, T; Strauss, P; Kratschmer, S; Paredes, D; Popescu, D; Landa, B; Guzman, G; Gomez, JA; Guernion, M; Zaller, JG; Batary, P | 2018 | Effects of vegetation management intensity on biodiversity and ecosystem services in vineyards: A meta-analysis | J APPL ECOL | 10.1111/1365-2664.13124 |
Ref30 | Alvarez, Roberto; Steinbach, Haydee S.; De Paepe, Josefina L. | 2017 | Cover crop effects on soils and subsequent crops in the pampas: A meta-analysis | Soil and Tillage Research 170, 53-65 | 10.1016/j.still.2017.03.005 |
Ref31 | Basche, AD; DeLonge, MS | 2017 | The Impact of Continuous Living Cover on Soil Hydrologic Properties: A Meta-Analysis | SOIL SCI SOC AM J, 81, 5, 1179-1190 | 10.2136/sssaj2017.03.0077 |
Ref32 | Bowles, TM; Jackson, LE; Loeher, M; Cavagnaro, TR | 2017 | Ecological intensification and arbuscular mycorrhizas: a meta-analysis of tillage and cover crop effects | Journal of applied ecology 54, 6, 1785-1793 | 10.1111/1365-2664.12815 |
Ref33 | Han, Z; Walter, MT; Drinkwater, LE | 2017 | N2O emissions from grain cropping systems: a meta-analysis of the impacts of fertilizer-based and ecologically-based nutrient management strategies | NUTRIENT CYCLING IN AGROECOSYSTEMS, 107, 335-355. | 10.1007/s10705-017-9836-z |
Ref34 | Marcillo GS, Miguez FE | 2017 | Corn yield response to winter cover crops: An updated meta-analysis | JOURNAL OF SOIL AND WATER CONSERVATION 72, 3, 226 -239 | 10.2489/jswc.72.3.226 |
Ref35 | Pecio A., Jarosz Z. | 2016 | Long-term effects of soil management practices on selected indicators of chemical soil quality [Wpływ wieloletniego stosowania zabiegów agrotechnicznych na wybrane właściwości chemiczne gleb] | Acta Agrobotanica 69, 2 | 10.5586/aa.1662 |
Ref36 | Wortman, Sam E. | 2016 | Weedy fallow as an alternative strategy for reducing nitrogen loss from annual cropping systems | Agronomy for Sustainable Development 61 | 10.1007/s13593-016-0397-3 |
Ref37 | Valkama E, Lemola R, Känkänen H, Turtola E | 2015 | Meta-analysis of the effects of undersown catch crops on nitrogen leaching loss and grain yields in the Nordic countries | Agriculture, Ecosystems & Environment 203, 93-101 | 10.1016/j.agee.2015.01.023 |
Ref38 | Basche, AD; Miguez, FE; Kaspar, TC; Castellano, MJ; | 2014 | Do cover crops increase or decrease nitrous oxide emissions? A meta-analysis | JOURNAL OF SOIL AND WATER CONSERVATION, 69, 471-482. | 10.2489/jswc.69.6.471 |
Ref39 | Quemada, M.; Baranski, M.; Nobel-de Lange, M. N. J.; Vallejo, A.; Cooper, J. M. | 2013 | Meta-analysis of strategies to control nitrate leaching in irrigated agricultural systems and their effects on crop yield | AGRICULTURE ECOSYSTEMS & ENVIRONMENT | 10.1016/j.agee.2013.04.018 |
Ref40 | Tonitto, C; David, MB; Drinkwater, LE | 2006 | Replacing bare fallows with cover crops in fertilizer-intensive cropping systems: A meta-analysis of crop yield and N dynamics | AGRICULTURE ECOSYSTEMS & ENVIRONMENT, 112, 58–72. | 10.1016/j.agee.2005.07.003 |
Disclaimer: These fiches present a large amount of scientific knowledge synthesised to assess farming practices impacts on the environment, climate and productivity. The European Commission maintains this WIKI to enhance public access to information about its initiatives. Our goal is to keep this information timely and accurate. If errors are brought to our attention, we will try to correct them. However, the Commission accepts no responsibility or liability whatsoever with regard to the information on these fiches
[1] Synthesis research papers include either meta-analysis or systematic reviews with quantitative results. Details can be found in the methodology section of the WIKI.
[2] Inglett, P.W., Reddy, K.R., Corstanje, R., 2005. Encyclopedia of Soils in the Environment | ScienceDirect.