Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Farming is driving force drying soil in Northern China

13.07.2015

An important agricultural region in China is drying out, and increased farming may be more to blame than rising temperatures and less rain, according to a study spanning 30 years of data.

A research team led by Purdue University and China Agricultural University analyzed soil moisture during the growing season in Northern China and found that it has decreased by 6 percent since 1983.


This is a map of soil moisture trends in Northern China during the growing seasons from 1983-2012. The shading shows the trend in satellite-observed surface soil moisture, and the circles represent monitoring stations within agricultural plots. A Purdue University-led research team found that farming was more of a driver in the drying of the soil than rising temperatures and declining rainfall. The change in volumetric water content is shown.

Credit: Purdue University image/Yaling Liu

The optimal soil-moisture level for farmland is typically 40 percent to 85 percent of the water holding capacity, and the region's soil is now less than 40 percent and getting drier. If this trend continues, the soil may not be able to support crops by as early as 2090, said study leader Qianlai Zhuang, Purdue's William F. and Patty J. Miller Professor of Earth, Atmospheric and Planetary Sciences and Agronomy.

"The soil moisture declined by 1.5 to 2.5 percent every decade of the study and, while climate change is still a factor, this water depletion appears to be largely driven by human activities," Zhuang said. "A 10 percent decline in soil moisture over the course of a century would have major implications for agriculture and the fresh water supply in this heavily populated area."

Forty percent of the nation's population resides in Northern China, according to the country's population census office. The region also accounts for 65 percent of the nation's cropland, Zhuang said.

"The drying of soil in Northern China has been well documented, but its causes and the impacts of agricultural intensification in general have been understudied," he said.

"This information is critical to improvement of agricultural practices and water resource management. The demand for food and water is increasing, but current practices to meet this demand threaten the future security of water resources. Unfortunately, with the growing world population, more and more regions could face the same circumstances of agricultural intensification for food security."

A paper detailing the results was published July 9 in Nature's Scientific Reports journal and is currently available online.

In addition to Zhuang, co-authors from Purdue include Yaling Liu, a former graduate student in the Department of Earth, Atmospheric and Planetary Sciences who is now a postdoctoral researcher at the Pacific Northwest National Laboratory; Tonglin Zhang, an associate professor of statistics; and Dev Niyogi, a professor of Earth, Atmospheric and Planetary Sciences and Indiana State Climatologist. Additional co-authors include Zhihua Pan, Pingli An, Zhiqiang Dong, Jingtin Zhang, Di He, Liewei Wang and Xuebiao Pan of China Agricultural University in Beijing; Diego G. Miralles, of the University of Ghent in Belgium; and Adriaan J. Teuling, of the Hydrology and Quantitative Water Management Group of Wageningen University in The Netherlands.

The team obtained direct observations recorded at 40 monitoring stations set up by the Chinese government within agricultural plots, and used available data of fertilizer use and crop types since 1983. The team also used satellite remote sensing of water content on the soil's surface and terrestrial water storage, meteorological observations and measurements of river discharge in their analysis.

The team also conducted a long-term study from 1983 to 2009 at two contiguous sites, one a pristine pasture and the other an agricultural site. The results showed a significant drying trend in the soil moisture in the cropland as opposed to a slight increase in the moisture of the pristine pasture soil.

The results showed a consistent trend in the reduction of soil moisture that correlated with increased fertilizer usage and the proliferation of crops with high water demands, like maize.

Fertilizer causes plants to grow larger and increases the number of leaves per plant. This leads to increased transpiration of water through pores on the leaves, called stomata. In addition, fertilizer use may aggravate soil compaction and soil salinity, which reduces the water holding capacity of soil and, consequently, reduces available soil water, Liu said.

"Fertilizer has been overused in China, which accounts for 31.4 percent of the total global consumption," Liu said. "Although the negative effects of using fertilizer in excess of the needs of the crop is recognized in the scientific community, it is difficult to reverse the farming practices."

While the increased use of fertilizer is not the only factor involved, the researchers found that it served as a broad diagnostic of the level of agricultural intensification. Other agricultural practices may also play a part in drying the land. For instance, newly developed crop varieties may demand more water and result in declining soil moisture, and increasing irrigation leads to rising withdrawals of surface freshwater and groundwater, she said.

"The results of this study underscore the importance of developing strategies for sustainable agriculture," Liu said. "Perhaps crops that require less water could be substituted, water-saving technologies like mulching, reduced tillage, drip irrigation and improved soil-crop system management could be employed more broadly and advances in agricultural technology could improve the situation. The Chinese government is very interested in this issue, and this work was an important step in the road to sustainability."

###

The National Basic Research Program of China, National Natural Science Foundation of China, National Science and Technology Support Program of China, National Non-profit Research Foundation for Agriculture of China, NASA Land Use and Land Cover Change program, U.S. Department of Energy and the National Science Foundation funded this research.

Writer: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu

Sources: Qianlai Zhuang, 765-494-9610, qzhuang@purdue.edu

Yaling Liu, 301-314-6724, yaling.liu@pnnl.gov, liu516@purdue.edu

Related websites:

http://www.eaps.purdue.edu/people/faculty-pages/zhuang.html

http://www.pnl.gov/science/staff/staff_info.asp?staff_num=8218

Note to Journalists: A Chinese language version of the news release is available upon request.

ABSTRACT

Agriculture intensifies soil moisture decline in Northern China

Yaling Liu, Zhihua Pan, Qianlai Zhuang, Diego G. Miralles, Adriaan J. Teuling, Tonglin Zhang, Pingli An, Zhiqiang Dong, Jingtin Zhang, Di He, Liwei Wang, Xuebiao Pan, Wei Bai & Dev Niyogi

Northern China is one of the most densely populated regions in the world. Agricultural activities have intensified since the 1980s to provide food security to the country. However, this intensification has likely contributed to an increasing scarcity in water resources, which may in turn be endangering food security. Based on in-situ measurements of soil moisture collected in agricultural plots during 1983-2012, we find that topsoil (0-50 cm) volumetric water content during the growing season has declined significantly (p<0.01), with a trend of -0.011 to -0.015m3m-3 per decade. Observed discharge declines for the three large river basins are consistent with the effects of agricultural intensification, although other factors (e.g. dam constructions) likely have contributed to these trends. Practices like fertilizer application have favored biomass growth and increased transpiration rates, thus reducing available soil water. In addition, the rapid proliferation of water-expensive crops (e.g. maize) and the expansion of the area dedicated to food production have also contributed to soil drying. Adoption of alternative agricultural practices that can meet the immediate food demand without compromising future water resources seem critical for the sustainability of the food production system.

Media Contact

Elizabeth K. Gardner
ekgardner@purdue.edu
765-494-2081

 @PurdueUnivNews

http://www.purdue.edu/ 

Elizabeth K. Gardner | EurekAlert!

More articles from Agricultural and Forestry Science:

nachricht Researchers discover natural product that could lead to new class of commercial herbicide
16.07.2018 | UCLA Samueli School of Engineering

nachricht Advance warning system via cell phone app: Avoiding extreme weather damage in agriculture
12.07.2018 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>