Minimizing Farming Impacts on Climate Change by Enhancing Carbon and Nitrogen Capture and Storage in Agro-Ecosystems - D1.50.16


Background:

The global climate is changing rapidly, leading to increasingly extreme weather events. A major cause of these events is the rising temperature in the Earth’s atmosphere, driven by increasing emission of greenhouse gases (GHGs) that trap heat in the atmosphere. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are the most important GHGs. Agriculture is generally considered as the victim of climate change; however, agriculture and land use changes contribute about 24% of the total anthropogenic GHGs and they continue to increase due to inappropriate land use changes and agricultural practices, increasing demand of food and animal protein for a growing human population, excessive use of chemical fertilizers, increasing numbers of ruminants and deforestation.

Minimizing farming impacts on climate change by enhancing carbon and nitrogen capture and storage in Agro-Ecosystems Of special importance among these GHGs is N2O which is approximately 300 times more powerful than CO2 in causing global warming and stays in the atmosphere for more than 120 years. N2O is emitted into the atmosphere by several microbial processes converting nitrogen (N) fertilizers and animal manure into N2O and gaseous nitrogen (N2).

To minimize N2O emission from soil, it is crucial to know what microbial processes are involved and how much N2O and N2 gases are emitted from soil after N fertilization or animal manure application. The nitrogen-15 stable isotope technique is currently the only method, to precisely identify these microbial processes of N2O production as well as trace the origin and extent of N2O and N2 gases.

Similarly, with CO2, whose concentration in the atmosphere started to increase at the start of the industrial revolution in the late eighteenth century, and CH4, whose concentration in the atmosphere has increased by more than 150% since 1750. As both gases contain a carbon atom, the movement and sources of these gases in the soil-atmosphere system can be precisely measured by the carbon-13 stable isotope technique and thereby provide information for mitigation of these GHGs.

Minimizing farming impacts on climate change by enhancing carbon and nitrogen capture and storage in Agro-EcosystemsMore efforts will therefore be required to strengthen the capacity of Member States to use nuclear techniques as tools to better understand the GHG emission from soil and to design food production strategies with lower environmental footprints. Only through the use of these stable isotope techniques, is it possible to obtain essential information on the sources and extent of agriculturally derived GHGs, information which is pivotal in global efforts to reduce these gases and develop the sustainable climate-smart agricultural practices that will shape the future.




Objective:

The objective of this CRP is to mitigate N2O emissions and minimize N losses from agricultural systems whilst enhancing agricultural productivity and sequestering C in soil.

Participants:

Ten countries participate in this CRP: seven research contract holders, one each from Brazil, Chile, China, Costa Rica, Ethiopia and Pakistan, two agreement holders from Estonia and Spain, and one technical contractor from Germany.

Activities:

This CRP was formulated on the Member States (MS) request to better understand the emissions of extent of agriculturally derived GHGs to design food production strategies with lower environmental footprints. The CRP proposal was presented to a panel of GHG experts for their feedback, review and suggestions in a meeting held at the IAEA headquarters, Vienna on 7–11 April 2014. After reviewing the CRP proposal by experts, proposals from MS were invited, and evaluated for final selection. The First Research Coordination Meeting (RCM) was held in Vienna, Austria on 3–7 November 2014. After the meeting, all CRP participants established field trials to assess the effects of using best agricultural practices on N2O emission and on C sequestration under different agro-climatic conditions. Measurements of N2O emissions and collection of soil and plant samples for chemical analyses have been conducted since 2015. The Second RCM was held in Justus Liebig University Giessen, Germany on 23–27 May. The third RCM was held in the Technical University, Madrid from 2–6 October 2017 to review project progress and develop work plans for the remaining two years. The mid-term review for the project was completed and approved by the CCRA in December 2017. The CRP is expected to continue for five years (2014–2019).

Key results:

  • The three years field data of Brazil, China, Chile, Iran and Pakistan showed that N2O emissions from different N inputs were reduced by approximately 50% by adopting best soil, nutrient and water management practices.
  • In Ethiopia, the soil C and N stocks decreased by 23% and 40%, respectively, after natural forest was converted to cropping system. However, after 17 years of afforestation, the cropping system showed no change of C or N stocks.
  • The N-15 technique identified 2 more microbial processes of N2O production which include co-denitrification and conversion of organic N to mineral N. This provides us more insights on how to exert more control on N2O production processes to reduce its emission from soil to the atmosphere.
  • Ten research papers on the effects of land use changes and farm management practices on emissions of GHGs and soil quality have been published in refereed scientific journals. Five more manuscripts on the effects of different farm management practices have been submitted to peer review journals.

Project Officer:

Mohammad Zaman and Lee Heng