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Data extracted in April 2021
Note to the reader: This general fiche summarises the environmental and climate impacts of FALLOWING found in a systematic review of 4 synthesis research papers [1]. These papers were selected from an initial number of 236 obtained through a systematic literature search strategy, according to the inclusion criteria reported in section 4.
As each synthesis research paper involves a number of primary research papers ranging from 35 to 127, the assessment of impacts relies on a large number of results obtained mainly in field experiments (carried out in situations close to real farming environment), and sometimes in lab experiments or from model simulations.
1. DESCRIPTION OF THE FARMING PRACTICE
Description |
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Key descriptors |
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2. DESCRIPTION OF THE IMPACTS OF THE FARMING PRACTICE ON CLIMATE AND THE ENVIRONMENT
We reviewed the impacts of fallowing (either natural or green fallows) compared to cultivated arable lands. The table below shows the number of synthesis papers reporting positive, negative, no effect, or uncertain effects. The numbers between parenthesis indicate the number of synthesis papers with a quality score of at least 50%. Details on quality criteria can be found in the methodology section of this WIKI.
Out of the 4 synthesis papers selected, 2 reported studies conducted in Europe and the 4 have a quality score higher than 50%. Some synthesis papers reported more than one impact.
Table 1. Impacts of fallowing (natural or green fallows) compared to cultivated arable land.
Impact | Intervention | Comparator | Positive | Negative | No effect | Uncertain |
Increase biodiversity | Natural fallow | Cultivated arable land | 1 (1) | 0 | 1 (1) | 0 |
Increase carbon sequestration | Natural fallow | 0 | 0 | 1 (1) | 0 | |
Increase crop yield | Natural fallow | 1 (1) | 0 | 1 (1) | 0 | |
Green fallow | 1 (1) | 0 | 0 | 0 |
3. DESCRIPTION OF THE KEY FACTORS INFLUENCING THE SIZE OF THE EFFECT
Only the factors explicitly studied in the reviewed synthesis papers with a significant effect are reported below. Details regarding the factors can be found in the Summaries of the meta-analyses.
Impact | Factors |
Increase biodiversity | Fallow area (Ref.5), fallow length (Ref.5) |
Increase crop yield | Fallow length (Ref.4), fertiliser recommended dose in post-fallow cropping season (%) (Ref.4), interaction between fertiliser recommended dose and post-fallow cropping season (Ref.4), post-fallow cropping season (Ref.4), site productivity (Ref.4) |
4.SYSTEMATIC REVIEW SEARCH STRATEGY
Keywords | TS= ((“fallow*” OR “uncrop*” OR “non-crop*” OR “unplant*” OR “unplow*” OR “uncultiv*” OR “non-cultiv*” OR “non-pasture*” OR “ungraz*”) OR ((“non-productive” OR “abandon*” OR “bare*” OR “unmanage*” OR “extensiv*” OR “extensificat*” OR “desintensificat*” OR “rotation” OR “set-aside” OR “set* aside”) NEAR/3 (land* OR crop* OR soil* OR field*))) AND TS= ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis") AND TS= (agricultur*) or TITLE-ABS-KEY ((“fallow*” OR “uncrop*” OR “non-crop*” OR “unplant*” OR “unplow*” OR “uncultiv*” OR “non-cultiv*” OR “non-pasture*” OR “ungraz*”) OR ((“non-productive” OR “abandon*” OR “bare*” OR “unmanage*” OR “extensiv*” OR “extensificat*” OR “desintensificat*” OR “rotation” OR “set-aside” OR “set* aside”) W/3 (land* OR crop* OR soil* OR field*))) AND ("meta-analy*" OR "systematic* review*" OR "evidence map" OR "global synthesis" OR "evidence synthesis" OR "research synthesis") AND (agricultur*) |
Search dates | No time restrictions |
Databases | Web of Science and Scopus, run in February 2021 |
Selection criteria | The main criteria that led to the exclusion of a synthesis paper were if the paper: (1) was out of the scope; (2) the duration of the fallowing was not as defined in the general fiche (we excluded fallow periods shorter than one crop year, or arable land taken out of production for more than 5-6 years); (3) dealt with shifting agriculture (practice usually conducted in tropical forest-agriculture where land is abandoned after cultivation for the regeneration of secondary forests); (4) the effect of fallowing was explored in combination with other practices (e.g. conservation agriculture) and it was not possible to disentangle the sole effect of fallowing; (5) was not a meta-analysis; (6) was not written in English. Synthesis papers that passed the relevance criteria were subject to critical appraisal carried out on paper-by-paper basis. The search returned 236 synthesis papers potentially relevant for the practice object of our fiche. From the 236 potentially relevant synthesis papers, 100 were excluded after reading the title and abstract, and 132 after reading the full text according to the above-mentioned criteria. Finally, 4 synthesis papers were selected for fallowing. |
5.LIST OF SYNTHESIS PAPERS INCLUDED IN THE REVIEW
Ref. Num | Authors | Year | Title | Reference | DOI |
1 | Koshida, C; Katayama, N | 2018 | Meta-analysis of the effects of rice-field abandonment on biodiversity in Japan | CONSERVATION BIOLOGY, 32(6), 1392-1402. | 10.1111/cobi.13156 |
2 | Kaempf, I; Hoelzel, N; Stoerrle, M; Broll, G; Kiehl, K | 2016 | Potential of temperate agricultural soils for carbon sequestration: A meta-analysis of land-use effects | SCIENCE OF THE TOTAL ENVIRONMENT, 566, 428-435. | 10.1016/j.scitotenv.2016.05.067 |
3 | Sileshi, G; Akinnifesi, FK; Ajayi, OC; Place, F | 2008 | Meta-analysis of maize yield response to woody and herbaceous legumes in sub-Saharan Africa | PLANT AND SOIL, 307, 1-19. | 10.1007/s11104-008-9547-y |
4 | Van Buskirk, J; Willi, Y | 2004 | Enhancement of farmland biodiversity within set-aside land | CONSERVATION BIOLOGY, 18(4), 987-994. | 10.1111/j.1523-1739.2004.00359.x |