Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tillage and reduced-input rotations affect runoff from agricultural fields

12.06.2013
No-till management practices can reduce soil erosion, but evidence suggests they can also lead to increased runoff of dissolved phosphorus from soil surfaces.

Meanwhile, farmers looking to avoid herbicides often have to combat weeds with tillage, which causes erosion. With all of the tradeoffs of different management systems, which one should growers use?

To answer that question, researchers from the USDA Agricultural Research Service compared nutrient and sediment loss from no-till, conventional tillage, and reduced-input rotation watersheds in a study published online today in Soil Science Society of America Journal.

By keeping a protective layer of plant matter on the soil surface, no-till practices reduce the loss of soil and phosphorus (P) attached to soil particles. But no-till requires herbicides to control weeds, and even after adoption of the practice by many farmers, harmful algal blooms were still occurring in surface waters. It looked as if no-till, while decreasing particulate P loss, was leading to increased runoff of dissolved P.

"Normally when you apply P-containing fertilizers, you would incorporate them into the soil," says Martin Shipitalo, lead author of the study. "With no-till, you're just broadcasting it on the soil surface, leading to high P concentrations at the surface. Even if you get less particulate loss, runoff will pick up that dissolved P that's highly concentrated at the soil surface."

Shipitalo and his team decided to look at data from a 16-year experiment to compare soil and nutrient runoff in watersheds managed in three different ways – no-till, conventional tillage (chisel-till), and reduced-input rotations. "The idea with the reduced-input rotation was to have a conservation practice that worked for farmers who do not want to use herbicides or large amounts of mineral fertilizers," explains Shipitalo.

In the current study, researchers provided most of the nutrients to crops in the reduced-input watersheds by planting red clover and spreading manure instead of fertilizers. They minimized the amount of bare soils and used just a shallow disking instead of total inversion tillage to leave some crop residue on the soil surface. While herbicides were used in the experiment, they aren't necessary because the light tilling and in-row cultivation that was done kept weeds under control.

"Reduced-input rotations strike a medium between conventional tillage and no-till," says Shipitalo. "And they could easily be adapted to be organic rotations."

As was expected, the researchers found that soil loss was lowest in no-till watersheds. Reduced-input fields, however, had the highest levels of soil loss. While levels were still below annual soil loss tolerance values, reduced-input practices led to soil loss levels of more than twice those from no-till fields.

To address the concern of dissolved P loss from no-till fields, the researchers compared runoff from conventional tillage and no-till watersheds. While the average loss of total dissolved P from no-till was slightly higher than from conventional tillage, the loss was still quite small. Also, average total P loss from no-till watersheds was actually smaller than that from conventional tillage watersheds.

The lack of large differences in P loss from these two management practices may in part be explained by something unexpected – earthworms. "The biology of the soil changes with long-term no-till," explains Shipitalo. "By leaving residue cover, you increase organic matter, and you increase earthworm populations."

But how are earthworms affecting transport of P? Earthworms can ingest and redistribute soil, and they enhance soil structure creating more stable aggregates and allowing water to move more rapidly into the soil. It is also possible that earthworm activity mixes up soil moving surface-applied P deeper into the soil and away from potential runoff.

So which management practice is best for farmers? No-till practices didn't lead to increased dissolved P runoff in this study, but they require herbicide use. Reduced-input rotations don't require herbicides, but they led to higher levels of soil loss. The authors suggest further work looking at other reduced-input rotations, perhaps some that use less tillage to tease out even more management options.

"It will depend on the situation and the philosophy of the growers," says Shipitalo. "There isn't a one-size-fits-all solution or a certain practice that is best for everyone."

While there may not be one solution, the increased understanding of the different practices and their tradeoffs provide a basis for farmers to choose a crop management system that is best for them, their crops, and their land.

View the abstract at: http://dx.doi.org/doi:10.2136/sssaj2013.01.0045

To obtain a copy of the complete article, please contact Madeline Fisher at 608-268-3973, mfisher@sciencesocieties.org or Caroline Schneider at 608-268-3976, cschneider@sciencesocieties.org.

The corresponding author, Martin Shipitalo, can be contacted at martin.shipitalo@ars.usda.gov.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://dl.sciencesocieties.org/publications/sssaj/

abstracts/0/0/sssaj2013.01.0045.

Soil Science Society of America Journal, http://www.soils.org/publications/sssaj, is a peer-reviewed international journal published six times a year by the Soil Science Society of America. Its contents focus on research relating to physics; chemistry; biology and biochemistry; fertility and plant nutrition; genesis, morphology, and classification; water management and conservation; forest, range, and wildland soils; nutrient management and soil and plant analysis; mineralogy; and wetland soils.

The Soil Science Society of America (SSSA) is a progressive, international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, SSSA is the professional home for 6,000+ members dedicated to advancing the field of soil science. It provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use. SSSA supports its members by providing quality research-based publications, educational programs, certifications, and science policy initiatives via a Washington, DC, office. Founded in 1936, SSSA proudly celebrated its 75th Anniversary in 2011. For more information, visit http://www.soils.org or follow @SSSA_soils on Twitter.

Martin Shipitalo | EurekAlert!
Further information:
http://www.usda.gov
http://www.soils.org

More articles from Agricultural and Forestry Science:

nachricht Energy crop production on conservation lands may not boost greenhouse gases
13.03.2017 | Penn State

nachricht How nature creates forest diversity
07.03.2017 | International Institute for Applied Systems Analysis (IIASA)

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: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Researchers shoot for success with simulations of laser pulse-material interactions

29.03.2017 | Materials Sciences

Igniting a solar flare in the corona with lower-atmosphere kindling

29.03.2017 | Physics and Astronomy

As sea level rises, much of Honolulu and Waikiki vulnerable to groundwater inundation

29.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>