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Data extracted in January 2023
Fiche created in December 2023
Note to the reader: This general fiche summarises all the environmental and climate impacts of WATER-SAVING IRRIGATION PRACTICES IN FLOODED LANDS found in a review of 13 synthesis papers[1]. These papers were selected from an initial number of 658 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 12 to 307. 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:
- Water-saving irrigation practices aim to reduce water use in irrigated fields. In flooded lands, specifically in rice paddy fields, the common feature of water-saving irrigation techniques is to keep the field in a water-free or thin water layer condition at a certain growth stage, by introducing short term drainage of flooding water during the rice cultivation.[2],[3]
- Continuous flooding corresponds to flooding rice paddies throughout the growing season.[4]
- Key descriptors:
- In this review, different water-saving irrigation practices applied in flooded lands are compared to continuous flooding.
- Water-saving irrigation practices in flooded lands in this review include:
- water-saving irrigation practices that vary according to the number of drainages applied during the rice growing season (single or multiple), irrigation water amount, and irrigation schedule (e.g. alternate wet and dry irrigation, intermittent irrigation, mid-season drainage, controlled irrigation, moist irrigation, shallow irrigation and deep storage, thin and wet irrigation),
- drip irrigation,
- dry cultivation,[5]
- and drill seeding methods[6]
- In some studies the effect of water-saving irrigation practice compared to continuous flooding is not provided separately for each water-saving practice.
- Please, note that this is not an exhaustive list of all water-saving irrigation techniques in flooded lands, but of those found in the synthesis papers that meet the requirements to be included in our review.
- Please, note that some water-saving irrigation practices included in this review were not clearly defined by the authors (e.g., moist irrigation, shallow irrigation and deep storage, thin and wet irrigation).
- This review does not present the results of the comparisons between water-saving and non-water saving irrigation practices in non-flooded lands and between no irrigation and non-water saving irrigation practices, as these two types of alternative comparisons are presented in two separate sets of fiches.
- This review does not include irrigation practices applied in non-agricultural land or in non-flooded lands.
2. EFFECTS OF THE FARMING PRACTICE ON CLIMATE AND ENVIRONMENTAL IMPACTS
We reviewed the impacts of water-saving irrigation practices applied in flooded lands (i.e. rice paddies) compared to continuous flooding (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 13 selected synthesis papers, 4 included studies conducted in Europe, and 13 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 | |
Decrease Air pollutants emissions | Ammonia emission | Water-saving irrigation practices in flooded lands | Continuous flooding | 1 | 0 | 1 | 0 |
Increase Carbon sequestration | Soil organic carbon | Water-saving irrigation practices in flooded lands | Continuous flooding | 0 | 1 | 0 | 0 |
Decrease GHG emissions | Carbon dioxide equivalent (CO2eq) emissions | Water-saving irrigation practices in flooded lands | Continuous flooding | 4 | 1 | 0 | 0 |
Carbon dioxide equivalent (CO2eq) emissions - yield scale | Water-saving irrigation practices in flooded lands | Continuous flooding | 3 | 0 | 0 | 0 | |
Methane (CH4) emission | Water-saving irrigation practices in flooded lands | Continuous flooding | 9 | 0 | 0 | 0 | |
Nitrous oxide (N2O) emission | Water-saving irrigation practices in flooded lands | Continuous flooding | 0 | 8 | 2 | 0 | |
Decrease Nutrient leaching and run-off | Nitrogen leaching loss | Water-saving irrigation practices in flooded lands | Continuous flooding | 1 | 0 | 1 | 0 |
Nitrogen runoff loss | Water-saving irrigation practices in flooded lands | Continuous flooding | 1 | 0 | 1 | 0 | |
Increase Plant nutrient uptake | Nitrogen use efficiency | Water-saving irrigation practices in flooded lands | Continuous flooding | 1 | 0 | 1 | 0 |
Increase Soil nutrients | Soil organic nitrogen | Water-saving irrigation practices in flooded lands | Continuous flooding | 0 | 0 | 1 | 0 |
Decrease Water use | Water supply | Water-saving irrigation practices in flooded lands | Continuous flooding | 3 | 0 | 0 | 0 |
Water use efficiency | Water-saving irrigation practices in flooded lands | Continuous flooding | 2 | 0 | 0 | 0 | |
Increase Crop yield | Crop yield | Water-saving irrigation practices in flooded lands | Continuous flooding | 3 | 7 | 4 | 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 |
Air pollutants emissions | N fertilisation (Ref3) |
Carbon sequestration | Mean annual precipitation (Ref8) |
GHG emissions | GHG emissions (Ref9), N fertilisation (Ref3), Organic fertiliser type (Ref7), Soil organic carbon (Ref7), Timing (Ref6) and Water management (Ref7) |
Nutrient leaching and run-off | N fertilisation (Ref3) |
Plant nutrient uptake | N fertilisation (Ref3) |
Water use | Soil properties * field management (Ref11) |
Crop yield | Degree of soil drying (Ref11), N fertilisation (Ref3), Soil organic carbon (Ref5), Soil pH (Ref11), Soil properties * field management (Ref11), Soil texture and soil type (Ref5), Timing of alternate wet and dry (Ref11), Water management (Ref7) and Water restriction amount (Ref5) |
4. SYSTEMATIC REVIEW SEARCH STRATEGY
Table 3: Systematic review search strategy - methodology and search parameters.
Parameter | Details |
Keywords | WOS: ((TS=((((“sustainab*” OR “improv*” OR “reduc*” OR “limit*” OR “deficit*” OR “efficien*”) NEAR “irrigat*”) OR ((“sustainab*” OR “improv*”) NEAR ((“water” NEAR (“use” OR “reuse”)) OR “water use efficiency” OR “WUE” OR “water productivity” OR “water harvest*” OR “water balance” OR “water quality” OR “water uptake” OR “water holding capacity”)) OR ((“sustainab*” OR “improv*”) NEAR (“water” NEAR (“management” OR “storage” OR “retention” OR “conservation” OR “infiltration”))) OR ((“sustainab*” OR “improv*”) NEAR (“water” NEAR (“blueprint” OR “footprint”)))) )) AND |
Time reference | No time restriction. |
Databases | Web of Science and Scopus: run on 24 January 2023 |
Exclusion criteria | The main criteria that led to the exclusion of a synthesis paper are: 1) The topic of the meta-analysis is out of the scope of this review, 2) The paper is neither a systematic review nor a meta-analysis of primary research, 3) The analysis is not based on pairwise comparisons, 4) The paper is not written in English, 5) The full text is not available and 6) The intervention (water-saving irrigation practice in flooded lands) and/or comparator (non water-saving irrigation practice OR another water-saving irrigation practice in flooded lands) are not clear. The search returned 636 synthesis papers from WOS and SCOPUS on Water-saving irrigation practices in flooded lands plus other 22 retrieved in the search of other farming practices, potentially relevant for the practice object of our fiche. |
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 | Chan, K; Bottomley, C; Saito, K; Lines, J; Tusting, LS | 2022 | The control of malaria vectors in rice fields: a systematic review and meta-analysis | Sci rep 12, 19694 (2022) | 10.1038/s41598-022-24055-2 |
Ref2 | Gu, XY; Weng, SM; Li, YE; Zhou, XQ | 2022 | Effects of Water and Fertilizer Management Practices on Methane Emissions from Paddy Soils: Synthesis and Perspective | Int. J. Environ. Res. Public health 2022, 19(12), 7324 | 10.3390/ijerph19127324 |
Ref3 | Qiu, HN; Yang, SH; Jiang, ZW; Xu, Y; Jiao, XY | 2022 | Effect of Irrigation and Fertilizer Management on Rice Yield and Nitrogen Loss: A Meta-Analysis | Plants 2022, 11(13), 1690 | 10.3390/plants11131690 |
Ref4 | Shang, ZY; Abdalla, M; Xia, LL; Zhou, F; Sun, WJ; Smith, P | 2021 | Can cropland management practices lower net greenhouse emissions without compromising yield? | Global change biology, 27, 4657–4670 | 10.1111/gcb.15796 |
Ref5 | He, G; Wang, ZH; Cui, ZL | 2020 | Managing irrigation water for sustainable rice production in China | Journal of cleaner production 245: 118928 | 10.1016/j.jclepro.2019.118928 |
Ref6 | Yagi, K; Sriphirom, P; Cha-un, N; Fusuwankaya, K; Chidthaisong, A; Damen, B; Towprayoon, S | 2020 | Potential and promisingness of technical options for mitigating greenhouse gas emissions from rice cultivation in Southeast Asian countries | Soil Science and Plant Nutrition, 66:1, 37-49 | 10.1080/00380768.2019.1683890 |
Ref7 | Jiang Y., Carrijo D., Huang S., Chen J., Balaine N., Zhang W., van Groenigen K.J., Linquist B. | 2019 | Water management to mitigate the global warming potential of rice systems: A global meta-analysis | Field crops research 2019, 234, 47-54 | 10.1016/j.fcr.2019.02.010 |
Ref8 | Livsey, J; Katterer, T; Vico, G; Lyon, SW; Lindborg, R; Scaini, A; Da, CT; Manzoni, S | 2019 | Do alternative irrigation strategies for rice cultivation decrease water footprints at the cost of long-term soil health? | Environ. Res. Lett. 14 074011 | 10.1088/1748-9326/ab2108 |
Ref9 | Zhao, X; Pu, C; Ma, ST; Liu, SL; Xue, JF; Wang, X; Wang, YQ; Li, SS; Lal, R; Chen, F; Zhang, HL | 2019 | Management-induced greenhouse gases emission mitigation in global rice production | Science of the total environment 2019, 649, 1299-1306 | 10.1016/j.scitotenv.2018.08.392 |
Ref10 | Linquist B.A., Marcos M., Arlene Adviento-Borbe M., Anders M., Harrell D., Linscombe S., Reba M.L., Runkle B.R.K., Tarpley L., Thomson A. | 2018 | Greenhouse gas emissions and management practices that affect emissions in US rice systems | Journal of Environmental Quality 2018, 47, 3, 395-409 | 10.2134/jeq2017.11.0445 |
Ref11 | Carrijo, DR; Lundy, ME; Linquist, BA | 2017 | Rice yields and water use under alternate wet and dry irrigation: A meta-analysis | Field crops research 2017, 203, 173-180 | 10.1016/j.fcr.2016.12.002 |
Ref12 | Nayak, D; Saetnan, E; Cheng, K; Wang, W; Koslowski, F; Cheng, YF; Zhu, WY; Wang, JK; Liu, JX; Moran, D; Yan, XY; Cardenas, L; Newbold, J; Pan, GX; Lui, YL; Smith, P | 2015 | Management opportunities to mitigate greenhouse gas emissions from Chinese agriculture | Agriculture ecosystems & environment 2015, 209, 108-124 | 10.1016/j.agee.2015.04.035 |
Ref13 | Feng, JF; Chen, CQ; Zhang, Y; Song, ZW; Deng, AX; Zheng, CY; Zhang, WJ | 2013 | Impacts of cropping practices on yield-scaled greenhouse gas emissions from rice fields in China: A meta-analysis | Agriculture ecosystems & environment 2013, 164, 220-228 | 10.1016/j.agee.2012.10.009 |
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 and WIKI.
[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] Qiu et al., 2022. Effect of Irrigation and Fertilizer Management on Rice Yield and Nitrogen Loss: A Meta-Analysis. Plants, 11(13), 1690; https://doi.org/10.3390/plants11131690
[3] Yagi et al., 2019. Potential and promisingness of technical options for mitigating greenhouse gas emissions from rice cultivation in Southeast Asian countries. SOIL SCIENCE AND PLANT NUTRITION, 66 (1), 37-49; https://doi.org/10.1080/00380768.2019.1683890
[4] Climate and Clean Air Coalition, 2014. https://www.ccacoalition.org/en/activity/paddy-rice-production
[5] Non-flooded rice but might be irrigated.
[6] Rice is continuously flooded from the 3–6 leaf stage to final drain for harvest.