Ottawa, 25 August, 2015. A recent research article published by a team of scientists lead by a CFFN scientist reports that utilization of farm yard manure (FYM) and cropping fodder grasses help reduce greenhouse gas (GHG) emissions from agricultural fields. Dr. Bharat Shrestha, an environmental researcher affiliated to CFFN, and his team evaluated the soil organic matter (SOM) quantity and quality in a long-term experimental farm in southern Norway. The experimental farm has been operational since 1953 with 6-year crop rotation cycles testing different crop combinations and different rate of nutrient applications. Another tillage experiment was started in 1983 with no-tillage and conventional tillage in the same experimental farm. They collected soil samples in summer of 2009. Soils were evaluated for physical and chemical soil parameters focusing mainly on different carbon species. They quantified the abundance of labile and recalcitrant carbon species in soil samples utilizing an advanced technology called nuclear magnetic resonance (NMR) spectroscopy in an Italian university.
Labile carbon is easily decomposed by micro-biota but recalcitrant carbon stays longer in the soil in normal climatic conditions. When these organic soils decompose, the carbon is released into the atmosphere in the form of CO2. With climate warming, the rate of decomposition increases rapidly for all types of carbon, thus producing more GHG emissions. A 10 ºC increase in temperature leads to 100% and 170% increase in decomposition rates of labile and recalcitrant carbon respectively. Researchers, Shrestha and others found that crop rotations and nutrient application rate did not show any difference in soil organic carbon stock even after 56 years while no-tillage system showed significantly higher amount of SOC after 26 years. However in terms of quality, SOM was found to differ by crop rotations, fertilizer application rate and by tillage systems. No-tillage systems showed an evidence of higher amount of labile carbon while conventional tillage showed abundance of recalcitrant carbon. Their long-term experiment found that adopting no-tillage system, including grass in crop rotation cycles, and applying FYM may help preserve soil fertility and mitigate climate change.
The research finding is interesting in Canadian and Nepalese contexts as well. Canada has adopted no-tillage systems since long ago and practices crop rotations. However, the application of chemical fertilizer has been increasing rapidly in the current decades. Applying FYM as a source of nutrient supply will reduce the crop production cost and GHG emissions from the field. In Nepalese mountain areas, FYM application is the traditional method of supplying nutrients to agricultural field. However, there has been increasing trend of chemical fertilizer application especially in commercial vegetable production. If they stick to FYM application and include fodder grass in their field in the crop rotation, it will be a win-win situation for farmer’s livelihood and economy, and for the environment. Public will get organic vegetable while mitigating effects of climate change.
The research article is published by British Society of Soil Science in their reputed journal Soil Use and Management. It is available here.