How can crop yields be raised cost-effectively in drylands?

Find the most cost-effective practices for raising crop yields and water productivity in arid and semi-arid regions.

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1	# How can crop yields be raised cost-effectively in drylands?
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3	In arid and semi-arid regions, crop yields are limited above all by water. Which practices raise yields there at a cost that farmers can bear?
4
5	## Question
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7	What are the most cost-effective methods to improve crop yields in arid and semi-arid areas? Candidates include water harvesting, conservation tillage and mulching, deficit and supplemental irrigation, and drought-tolerant varieties; cost-effectiveness includes whether farmers can afford and adopt them.
8
9	## Background
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11	The question is in the theme "enhancing resilience of agriculture to climate change" of the 100 essential questions for the future of agriculture, compiled from 419 questions submitted worldwide in 2022. The authors note that changing temperature and precipitation and more frequent extremes threaten production, soil health and water access [1].
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13	## What is known
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15	- A global meta-analysis of 5,463 paired yield observations found that no-till generally reduces yields, but combined with residue retention and crop rotation it significantly increases rainfed productivity in dry climates; these practices are often hard to implement in resource-poor smallholder systems [2].
16	- A meta-analysis of 1,310 yield observations from 74 studies in 19 countries found that plastic or straw mulching increased maize and wheat yields, water-use efficiency and nitrogen-use efficiency by up to 60%, with effects declining as water input rises [3].
17	- Process-based modelling suggests that more efficient irrigation, with the saved water rerouted to rainfed fields, together with low-tech practices on rainfed land such as water harvesting, could raise global production by 41% and close 62% of the water-related yield gap [4].
18	- Water harvesting raises crop yields significantly, most in low-rainfall years, but where agricultural productivity is low the returns to investment are limited, so smallholders may be reluctant to invest [5].
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20	## What would count as progress
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22	No single result settles a question like this; contributions like these would move it forward:
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24	- Multi-site, multi-year field trials in drylands that compare packages of practices on yield, water use and farmer profit, with costs reported and data released openly.
25	- Cost-effectiveness analyses (cost per tonne of extra grain or per cubic metre of water saved) across regions, including side effects such as plastic residues from mulch.
26	- Models of adoption that predict where farmers will take up a practice, validated against observed uptake.
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28	## References
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30	1. Hu, Y. et al. (2023). [100 essential questions for the future of agriculture](https://doi.org/10.1002/moda.5). Modern Agriculture 1(1), 4–12.
31	2. Pittelkow, C. M. et al. (2015). [Productivity limits and potentials of the principles of conservation agriculture](https://doi.org/10.1038/nature13809). Nature 517(7534), 365–368.
32	3. Qin, W., Hu, C. & Oenema, O. (2015). [Soil mulching significantly enhances yields and water and nitrogen use efficiencies of maize and wheat: a meta-analysis](https://doi.org/10.1038/srep16210). Scientific Reports 5, 16210.
33	4. Jägermeyr, J. et al. (2016). [Integrated crop water management might sustainably halve the global food gap](https://doi.org/10.1088/1748-9326/11/2/025002). Environmental Research Letters 11(2), 025002.
34	5. Bouma, J. A., Hegde, S. S. & Lasage, R. (2016). [Assessing the returns to water harvesting: a meta-analysis](https://doi.org/10.1016/j.agwat.2015.08.012). Agricultural Water Management 163, 100–109.
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36	## Source
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38	Imported from [100 essential questions for the future of agriculture, question 4](https://doi.org/10.1002/moda.5), curated by Hu et al. Listed as open in the source (2023) and still an active research question as of 2026-10-20. The statement above is written in our own words; see the source for the original wording, history and discussion.