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Topic · Civil and Structural Engineering

Soil and Unsaturated Flow

Soil and Unsaturated Flow is a research topic within Civil and Structural Engineering. Science Explorer counts 42k research works in it since 1950. 10.0% of them reached the world's top 10% most cited for their field and year.

This cluster of papers focuses on the mechanics and transport phenomena in unsaturated soils, with an emphasis on soil hydraulic properties, pedotransfer functions, soil water characteristic estimation, hydraulic conductivity, soil water retention, clay minerals behavior, macropore flow, thermal effects on soil, and root water uptake.

  • Unsaturated Soil Mechanics
  • Soil Hydraulic Properties
  • Pedotransfer Functions
  • Soil Water Characteristic
  • Hydraulic Conductivity
  • Soil Water Retention
  • Clay Minerals Behavior
  • Macropore Flow
  • Thermal Effects on Soil
  • Root Water Uptake
Research works
42k
fractional, since 1950
In the world top 10%
4.2k
per year above
Top-10% rate
10.0%
share of its works in the world top 10%
Growth, 2018-21 → 2022-25
+1%
the tick is no change
Largest producer
China
55% of the 10 largest, 2022-now
Soil and Unsaturated Flow

Which countries lead Soil and Unsaturated Flow research?

By volume, China and the United States publish the most (3.2k and 748 works in 2022-now).

By volume, 2022-now

  1. 1 China 3.2k works
  2. 2 United States 748 works
  3. 3 India 485 works
  4. 4 Germany 236 works
  5. 5 France 234 works
  6. 6 Canada 199 works
  7. 7 Japan 195 works
  8. 8 Brazil 180 works
  9. 9 Iran 178 works
  10. 10 United Kingdom 174 works

How concentrated that is

The same countries as shares of everything the list above accounts for. A node where two countries do two thirds of the work and one spread evenly across twelve read alike as a ranking and not at all alike here.

China: 55.1%United States: 12.8%India: 8.3%Germany: 4.0%6 others listed: 19.8%55%largest
China3,220 · 55.1%United States748 · 12.8%India485 · 8.3%Germany236 · 4.0%6 others listed1,160 · 19.8%

Shares of the rows listed above, not of the whole node.

Which institutions lead Soil and Unsaturated Flow research?

By volume in 2022-now, Chinese Academy of Sciences publishes the most Soil and Unsaturated Flow research, followed by Centre National de la Recherche Scientifique and Tongji University.

By volume, 2022-now

  1. 1 Chinese Academy of SciencesChina 285 works
  2. 2 Centre National de la Recherche ScientifiqueFrance 84 works
  3. 3 Tongji UniversityChina 82 works
  4. 4 Hohai UniversityChina 81 works
  5. 5 Chang'an UniversityChina 68 works
  6. 6 University of Chinese Academy of SciencesChina 58 works
  7. 7 Chinese Academy of Agricultural SciencesChina 54 works
  8. 8 Northwest A&F UniversityChina 50 works
  9. 9 Zhejiang UniversityChina 49 works
  10. 10 China University of Mining and TechnologyChina 42 works

Who are the leading researchers in Soil and Unsaturated Flow?

The most-cited researchers publishing on Soil and Unsaturated Flow include George Davey Smith, Jun Wang and Donald B. Rubin.

  1. 1 George Davey Smith United Kingdom 435k citations
  2. 2 Jun Wang China 340k citations
  3. 3 Donald B. Rubin United States 301k citations
  4. 4 Mark A. Bradford United States 268k citations
  5. 5 Philippe Ciais France 237k citations
  6. 6 Kai You Wang China 224k citations
  7. 7 Albert-Ĺaszló Barabási United States 223k citations
  8. 8 Guangming Zeng China 204k citations
  9. 9 Harry Eugene Stanley United States 198k citations
  10. 10 Hua Zhang Singapore 196k citations

Ranked by citations received across their whole record, among researchers with at least three works on this topic.

What are the most cited papers in Soil and Unsaturated Flow?

The most cited paper in Soil and Unsaturated Flow is "A Closed‐form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils" (Martinus Th. van Genuchten, 1980), with 27,905 citations. Next come "Diagnosis and Improvement of Saline and Alkali Soils" (9,313) and "Chloroform fumigation and the release of soil nitrogen: A rapid direct extraction method to measure microbial biomass nitrogen in soil" (5,901).

Most cited papers
#PaperReleasedCitations
1 A Closed‐form Equation for Predicting the Hydraulic Conductivity of Unsaturated Soils Martinus Th. van Genuchten · Soil Science Society of America Journal Sep 1980 27,905
2 Diagnosis and Improvement of Saline and Alkali Soils L. A. Richards · Soil Science Aug 1954 9,313
3 Chloroform fumigation and the release of soil nitrogen: A rapid direct extraction method to measure microbial biomass nitrogen in soil P. C. Brookes, A. Landman, Gordon Pruden et al. · Soil Biology and Biochemistry 1985 5,901
4 A simple hydrologically based model of land surface water and energy fluxes for general circulation models Xu Liang, Dennis P. Lettenmaier, Eric F. Wood et al. · Journal of Geophysical Research Atmospheres 20 Jul 1994 4,252
5 Analysis of Factors Controlling Soil Organic Matter Levels in Great Plains Grasslands W. J. Parton, D. Schimel, C. V. Cole et al. · Soil Science Society of America Journal Sep 1987 3,845
All 100 most cited papers, with filters and sorting

Where is Soil and Unsaturated Flow research done?

The largest centres of Soil and Unsaturated Flow research in 2022-now are Beijing (China), Nanjing (China), Wuhan (China) and Xi'an (China). Among places with at least 20 works in it, it is an unusually large share of all research in Yangling, Yangling and Champs-sur-Marne.

Largest cities, 2022-now

  1. 1 BeijingChina 659 works
  2. 2 NanjingChina 221 works
  3. 3 WuhanChina 194 works
  4. 4 Xi'anChina 193 works
  5. 5 ShanghaiChina 161 works
  6. 6 LanzhouChina 108 works
  7. 7 HangzhouChina 102 works
  8. 8 ChengduChina 98 works
  9. 9 ChangshaChina 80 works
  10. 10 TehranIran 68 works

Where it is the local speciality

  1. YanglingCN · 28.1 works81×
  2. YanglingCN · 49.7 works17×
  3. Champs-sur-MarneFR · 27.5 works15×
← less than its size predicts1×more →

Location quotient: how much more of its research is in Soil and Unsaturated Flow than the world average.

See Soil and Unsaturated Flow on the map

Where is the best place to study Soil and Unsaturated Flow?

Among universities, judged by research, Chang'an University, Hong Kong University of Science and Technology and China University of Geosciences score highest, combining excellence, specialisation, size, growth and international reach. Research strength is one signal when choosing where to study; it does not measure teaching.

0%10%20%30%mean 17.75%fractional works in this field (log) →share of work in the world top 10% →Hong Kong University…Wuhan UniversityChina University of …Chang'an University
above the meannear itbelow it

One dot per university in the first ten of the table below, at the default weights. The upper left is the interesting corner: small places doing unusually strong work.

Excellenceshare of its work in the world top 10%, 2022-now and all time averaged
40%
Specialisationhow much of its work is in this field, counted up to 10× the world share
10%
Sizeits output in this field, on a log scale
30%
Growthoutput growth, counted from -20% to +20%
10%
Internationalshare of its work with a co-author abroad
10%
Each slider sets a weight; the share it gets of the score is beside it.
#UniversityScoreTop 10%SpecialisationWorksGrowth
1Chang'an UniversityChina 72.718.2%26.6×68 +26.6%
2Hong Kong University of Science and TechnologyChina 70.724.7%8.1×23 +4.5%
3China University of GeosciencesChina 66.119.2%12.5×39 +50.6%
4Wuhan UniversityChina 66.124.3%3.9×38 +40.0%
5Northwest A&F UniversityChina 65.717.7%18.8×50 -0.6%
6Hong Kong Polytechnic UniversityChina 65.717.8%4.7×27 +56.8%
7Hohai UniversityChina 62.512.0%20.3×81 +6.2%
8University of Chinese Academy of SciencesChina 62.316.0%5.2×58 -0.7%
9Tongji UniversityChina 60.65.9%7.8×82 +58.6%
10Nanjing UniversityChina 60.221.7%4.0×25 +19.5%

Universities only. The score blends excellence (40%), size (30%), specialisation (10%), growth (10%), international reach (10%), 2022-now; growth compares 2018-21 with 2022-25 and counts up to +20%, since a jump from a small base is mostly noise.

Every institution in Soil and Unsaturated Flow, country by country

Is Soil and Unsaturated Flow research growing?

Output in 2022-2025 was 1% higher than in 2018-2021, peaking in 2021. The fastest-growing topics are Soil and Unsaturated Flow.

still counting19801990200020102020
grewheldshrank

The same series as a ribbon: one cell per year, darker for more. The line above answers how much; this answers when.

Its share of all research

Growing output can still be a shrinking share: all of science grows. This is Soil and Unsaturated Flow as a percentage of every work published that year, 0.031% in 2024.

still counting0.020%0.040%0.060%Soil and Unsaturated Flow0.029% in 202519801990200020102020

Fractional works of Soil and Unsaturated Flow over all fractional works that year. How the balance of science has shifted.

How much of it reaches the world top 10%

Year by year.

still counting5%10%15%Soil and Unsaturated Flow9.9% in 2025200020102020

Of each year's works in it, the share that reached the world's 10% most cited for their field and year. A field is the world for its own topics, so there is no other line to hold it against.

Which topics inside it are moving

Growth and decline on one axis around a shared zero. Two lists side by side hide the thing that matters: whether the growth dwarfs the decline, or the other way round.

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