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Data extracted in January 2023
Fiche created in November 2023
Note to the reader: This general fiche summarises all the environmental and climate impacts of NO IRRIGATION found in a review of 14 synthesis papers[1]. These papers were selected from an initial number of 660 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 17 to 209. 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:
- No-irrigation corresponds to rainfed (or non-irrigated) agriculture, where the soil water available to plants comes mainly from rainfall.[2]
- Non water-saving irrigation practices are standard techniques of irrigation that supply water to the crop in order to increasing crop productivity, with no intention of minimising water use. They rely on various techniques such as flooding or use of sprinklers.[3]
- Water-saving irrigation practices aim to satisfy crop water requirements while improving the timing and reliability of water deliveries to minimize water use.[4]
- Key descriptors:
- In this review, no irrigation is compared to:
- non water-saving irrigation practices applied in non-flooded lands such as sprinkler irrigation, furrow irrigation, centre pivot irrigation, full or supplemental irrigation.
- non water-saving irrigation practices applied in flooded rice fields, corresponding to a continuous flooding throughout the rice growing season.[5]
- water-saving irrigation practices aiming to improve water use efficiency in non-flooded lands. Those included in this review were techniques based on reduced irrigation amounts or improved irrigation timing (i.e. irrigation in the over-wintering, jointing, and booting stages).
- any type of irrigation. In this review, two studies reported the impact of both non water-saving irrigation (e.g. sprinkler irrigation) and water-saving irrigation (e.g. drip irrigation) practices methods, without distinguishing the effects of each category of practices.
- Note that the list above is not exhaustive, but covers the practices found in the synthesis papers that meet the requirements to be included in our review.
- This review does not present the results of the comparisons between water-saving and non-water saving practices as these comparisons are presented in two separate set of fiches entitled “Water-saving irrigation in flooded lands” and “Water-saving irrigation in non-flooded lands”.
- This review does not include irrigation practices applied in non-agricultural land.
2. EFFECTS OF THE FARMING PRACTICE ON CLIMATE AND ENVIRONMENTAL IMPACTS
We reviewed the impacts of no irrigation, compared to three groups of comparators: non water-saving irrigation practices (Table 1a), water-saving irrigation practices (Table 1b), and any irrigation practices (Table 1c).
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 14 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 | |
Increase Carbon sequestration | Total organic carbon | No irrigation | Any type of irrigation (i.e., non water-saving or water-saving irrigation practices) | 0 | 0 | 0 | 1 |
Decrease GHG emissions | CH4 emission | No irrigation | Continuous long-term flooding | 1 | 0 | 0 | 0 |
Decrease Global warming potential (LCA) | Yield-scaled greenhouse gas emissions | No irrigation | Improved irrigation timing | 1 | 1 | 0 | 0 |
No irrigation | Non water-saving irrigation practices | 1 | 1 | 0 | 0 | ||
No irrigation | Optimised irrigation amount | 1 | 1 | 0 | 0 | ||
Decrease Nutrient leaching and run-off | Nitrate leaching | No irrigation | Non water-saving irrigation practices | 1 (0) | 0 | 0 | 0 |
Increase Plant nutrient uptake | Nutrient use efficiency | No irrigation | Non water-saving irrigation practices | 0 | 2 | 0 | 0 |
Increase Soil water retention | Soil water content | No irrigation | Any type of irrigation (i.e., non water-saving or water-saving irrigation practices) | 0 | 0 | 0 | 1 |
No irrigation | Improved irrigation timing | 0 | 0 | 0 | 1 | ||
No irrigation | Non water-saving irrigation practices | 1 | 1 | 0 | 1 | ||
No irrigation | Optimised irrigation amount | 0 | 0 | 0 | 1 | ||
Decrease Water use | Water use efficiency | No irrigation | Any type of irrigation (i.e., non water-saving or water-saving irrigation practices) | 0 | 1 | 0 | 0 |
No irrigation | Improved irrigation timing | 0 | 0 | 1 | 0 | ||
No irrigation | Non water-saving irrigation practices | 1 | 4 | 3 | 0 | ||
No irrigation | Optimised irrigation amount | 0 | 0 | 1 | 0 | ||
No irrigation | Water-saving irrigation practices | 0 | 1 | 0 | 0 | ||
Increase Crop yield | Crop yield | No irrigation | Any type of irrigation (i.e., non water-saving or water-saving irrigation practices) | 0 | 1 | 0 | 1 |
No irrigation | Continuous long-term flooding | 0 | 1 | 0 | 0 | ||
No irrigation | Improved irrigation timing | 0 | 1 | 1 | 0 | ||
No irrigation | Non water-saving irrigation practices | 0 | 7 | 2 | 0 | ||
No irrigation | Optimised irrigation amount | 0 | 2 | 1 | 0 | ||
No irrigation | Reduced irrigation water amount | 0 | 1 | 1 | 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 |
Global warming potential (LCA) | Type of water used (Ref13) |
Plant nutrient uptake | Annual precipitation (Ref7), Irrigation amount (Ref7), Irrigation times (Ref7), N application rate (Ref7) and Soil total N (Ref7) |
Water use | Annual precipitation (Ref3, Ref8, Ref10), Annual temperature (Ref3), Crop type (Ref8), Experimental duration (Ref3), Humidity (Ref4), Irrigation amount (Ref3, Ref4, Ref8, Ref10), Irrigation frequency and duration (Ref1), Irrigation method (Ref1, Ref4), Irrigation timing (Ref3), Mean annual temperature (Ref1), Mineral N fertiliser amount applied (Ref8), N application rate (Ref10), N fertilization (Ref3), Planting time (Ref8), Soil bulk density (Ref10), Soil characteristics (Ref3), Soil organic matter (Ref10), Soil type (Ref1, Ref8) and Year of study (Ref8) |
Crop yield | Annual precipitation (Ref10, Ref13), Annual temperature (Ref10), Humidity (Ref4), Irrigation amount (Ref4, Ref10), Irrigation method (Ref4), N application rate (Ref10, Ref13), Productivity (Ref11), Soil bulk density (Ref10), Soil organic matter (Ref10) and Soil texture (Ref13) |
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: |
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 | Zhang, GX; Zhang, Y; Zhao, DH; Liu, SJ; Wen, XX; Han, J; Liao, YC | 2023 | Quantifying the impacts of agricultural management practices on the water use efficiency for sustainable production in the Loess Plateau region: A meta-analysis | Field Crops Research, 291: 108787 | 10.1016/j.fcr.2022.108787 |
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 | Liu, BY; Liu, WS; Lin, BJ; Liu, WX; Han, SW; Zhao, X; Zhang, HL | 2022 | Sustainable management practices to improve the water use efficiency of winter wheat in the North China Plain: a meta-analysis | Agronomy for Sustainable Development 2022, 42 (2), pp.33. | 10.1007/s13593-022-00766-8 |
Ref4 | Yang, ZH; Hu, Y; Zhang, S; Raza, S; Wei, XR; Zhao, XN | 2022 | The Thresholds and Management of Irrigation and Fertilization Earning Yields and Water Use Efficiency in Maize, Wheat, and Rice in China: A Meta-Analysis (1990-2020) | Agronomy 2022, 12(3), 709 | 10.3390/agronomy12030709 |
Ref5 | Liu B.-Y., Lin B.-J., Li X.-X., Virk A.L., N'dri Yves B., Zhao X., Dang Y.P., Zhang H.-L. | 2021 | Appropriate farming practices of summer maize in the North China Plain: Reducing nitrogen use to promote sustainable agricultural development | Resources, Conservation and Recycling 175,105889 | 10.1016/j.resconrec.2021.105889 |
Ref6 | Jing, BH; Wang, C; Khan, S; Yuan, YC; Yang, WD; Feng, MC | 2020 | Yield response of winter wheat (Triticum aestivum l.) to water stress in northern China: A meta-analysis | Applied Ecology and Environmental Research 18(1): 433-446. | 10.15666/aeer/1801_433446 |
Ref7 | Liu, BY; Zhao, X; Li, SS; Zhang, XZ; Virk, AL; Qi, JY; Kan, ZR; Wang, X; Ma, ST; Zhang, HL | 2020 | Meta-analysis of management-induced changes in nitrogen use efficiency of winter wheat in the North China Plain | Journal of Cleaner Production 251: 119632. | 10.1016/j.jclepro.2019.119632 |
Ref8 | Mitchell-McCallister, D; Cano, A; West, C | 2020 | Meta-analysis of crop water use efficiency by irrigation system in the Texas High Plains | Irrigation Science 38: 535-546. | 10.1007/s00271-020-00696-x |
Ref9 | Lee H., Lautenbach S., Nieto A.P.G., Bondeau A., Cramer W., Geijzendorffer I.R. | 2019 | The impact of conservation farming practices on Mediterranean agro-ecosystem services provisioning—a meta-analysis | Regional Environmental Change 2019, 19, 2187–2202 | 10.1007/s10113-018-1447-y |
Ref10 | Zheng, HF; Ying, H; Yin, YL; Wang, YC; He, G; Bian, QQ; Cui, ZL; Yang, QH | 2019 | Irrigation leads to greater maize yield at higher water productivity and lower environmental costs: a global meta-analysis | Agriculture, Ecosystems & Environment 2019, 273, 62-69 | 10.1016/j.agee.2018.12.009 |
Ref11 | Magombeyi M.S., Taigbenu A.E., Barron J. | 2018 | Effectiveness of agricultural water management technologies on rainfed cereals crop yield and runoff in semi-arid catchment: a meta-analysis | International Journal of Agricultural Sustainability 2018, 16:4-5, 418-441 | 10.1080/14735903.2018.1523828 |
Ref12 | Daryanto S., Wang L., Jacinthe P.-A. | 2017 | Can ridge-furrow plastic mulching replace irrigation in dryland wheat and maize cropping systems? | Agricultural Water Management 2017, 190, 1-5. | 10.1016/j.agwat.2017.05.005 |
Ref13 | He, G; Cui, ZL; Ying, H; Zheng, HF; Wang, ZH; Zhang, FS | 2017 | Managing the trade-offs among yield increase, water resources inputs and greenhouse gas emissions in irrigated wheat production systems | Journal of Cleaner Production 2017, 164, 567-574 | 10.1016/j.jclepro.2017.06.085 |
Ref14 | Sharma S., Chaubey I. | 2017 | Surface and subsurface transport of nitrate loss from the selected bioenergy crop fields: Systematic review, analysis and future directions | Agriculture 2017, 7(3), 27 | 10.3390/agriculture7030027 |
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] Molden et al., 2007. Water for Food, Water for Life, Chapter 1, Setting the scene. ed. David Molden, Earthscan, London and International Water Management Colombo: Institute. Available at: https://www.iwmi.cgiar.org/assessment/Water%20for%20Food%20Water%20for%20Life/Chapters/Chapter%201%20Setting%20the%20Scene.pdf
[3] European Parliamentary Research Service, 2019. Irrigation in EU agriculture. Available at: https://www.europarl.europa.eu/RegData/etudes/BRIE/2019/644216/EPRS_BRI(2019)644216_EN.pdf
[4] FAO, 2017. Does improved irrigation technology save water? Available at: https://www.fao.org/3/I7090EN/i7090en.pdf
[5] Climate and Clean Air Coalition, 2014. https://www.ccacoalition.org/en/activity/paddy-rice-production