Soil health and carbon sequestration: the beginning of carbon footprint in products

For the man in the street, the rise in atmospheric greenhouse gases (GHG) concentration linking it to global warming and increased climate variability means little, and lesser still the small increases in soil carbon (C) over large areas of forests and plantation tree forests inclusive of oil palm, rubber and cocoa can contribute significantly by their effects of sequestrating C in plant biomass and soils to the mitigation of Malaysian GHG emissions. The increase in soil organic matter (SOM) wrhich has always been recognised as an important technique in global warming solution, improvement in soil health, fertility and resilience to withstand variation of seasonal changes in crop productivity is not felt by the public. Therefore this needs to change as any inclusion of the soil C arising from the overall effect of C sequestration in capturing and securing C storage by biotic means such as photosynthesis and abiotic processes through injecting CO₂ into geological strata or ocean will be given greater emphasis. However several barriers need to be overcome before such C offsets can be recognised and used in an emission trading scheme. To date there is no agreement to the land use approach. The four major barriers discussed are: Credibility, cost effective and acceptable methods of estimating soil C change, an effective system for assessing compliances and mechanisms to deal with non-permanence. By increasing CO₂ fixation through photosynthesis and its distribution of assimilates to the above-and below-ground biomass and root and subsequently through the root decay and litter fall, the soil C sequestered which invariably improves soil health and soil organic matter will enable trees and agricultural soils to decrease the net GHG emissions to the atmosphere. High CO₂ concentrations in the biomass and soils will also raise the long-term productivity of crops. The role of plant breeding in providing a wide variety of genotypes for crops and ground covers will remain valuable under future climatic scenarios and their likely impacts along spatial, temporal and biological scales. Thus the role of soil C sequestration to reduce GHG emissions which has always been achieved through the use of best practice benchmarks that are based on regional and sectoral 'best practice' for emissions intensity level reductions is one way that the agriculture sector could contribute to society by generating C credits. Best practices such as zero burn, no-tillage, biological nitrogen fixation by legume species, enhancing riparian strips along the edges of waterways, conservation terraces and prevention of soil erosion, recycling of organic amendments like empty fruit bunches, land application of palm oil mill effluent, long term storage of C in wood products practices and more recently of using biochar, all have been found to mitigate GHG emissions. For the plantations, the science to support these best practices is well advanced and many are already implemented but yet further research is required to improve this capacity. Understanding that the C cycle, simplified into five reservoirs of atmosphere, soils, vegetation, ocean and sediments which include fossil fuels, can provide a clearer picture of how plant growth processes and decay characteristics can contribute to the long-term storage of C in plants and soils. With improved understanding at the process level, land-based GHG mitigation policies will be better informed and the development and application of good management practices will take greater cognisance of the movement of C from one reservoir to another. With this any response to implement different best practices both in the past and into the future will require us to understand how much the various chemical, physical, geological and biological processes will interplay. Therefore prioritising research efforts towards alternative mitigation options should be stepped up and be based on the analysis of the potential mitigation that can be achieved through these measures. Potential mitigation will be influenced by the magnitude of the emissions attributable to that source and the technical and economic capacity to achieve reduction in emissions from that source. Hence the assessment should consider: The whole farm system which may include a variety of land use e.g. oil palm, rubber, cocoa, livestock, etc: The full life cycle including direct as well as indirect emissions e.g. those associated with manufacture and mining of fertilisers for use in oil palm , rubber and cocoa. Off-site impacts e.g. land use change at one location can have positive or negative impacts elsewhere e.g. fertiliser application followed by heavy rain carry nutrients at one location to another and may affect eutrophication downstream. Next we need to look at the probable impacts of climate change on viability of any option which must consider the rigorous life cycle analysis (LCA). The net GHG reduction from the different options must be quantified. Thus, as an example, the environmental impact of agriculture on food production and its consequence on food services providers on C emissions has to take a long-term view on process of soil and biomass C sequestration. A greater awareness of the importance of the LCA approach on this subject is stressed since the net C in sinks is one of the more important resources that is dedicated to global warming solution. The need to look at the overall soil health with emphasis on soil C sequestration is to develop a GHG emissions inventory tool that will improve the quantification of the GHG removal from the atmosphere from food production and food procurement. Two aspects to be emphasised are: Understanding C sequestration and emissions to get the net C impact higher has other benefits. Soil C is vital for retaining water and nutrients. The amount of C stored in the soil is influenced by past and present management practices and by climate. Climate affects C sequestration by modifying the length of time it takes to mineralise soil organic C into CO₂. Understanding soil and climatic conditions provide a better opportunity for plantation companies to sequester a larger amount of soil C. As a consequence, sequestering soil C via best agricultural practices is therefore gaining popularity and has even generated worldwide interest and research effort due to the potential benefits of improving both agricultural productivity and reducing atmospheric CO2 concentration simultaneously. For soil C sequestration to be quantified, the net GHG emissions from the soils over the life cycle of the agricultural production of food should be extended with boundary setting to cover the GHG emitted by the eventual preparation of the food grown and produced, and prepared as cooked food on the table. The latter is looked upon as a major component of the efforts to reduce the anthropogenic environmental impacts of agriculture and food production on the C footprint. For this to happen, the practical collection of data according to the inventory of the GHG emissions will pave way later for the ordinary household and food service providers to do their part to reduce the GHG emission via food procurement practices. Currently, there are no direct applications of life cycle assessment (LCA) of the GHG inventory for use by the food producers and food service providers. The need to devise some guidance for them based on LCA approach for measuring the net environmental impacts of preparing a meal (activity) from a product cover the following: Firstly, develop process LCA (PLCA) to estimate the impacts of a food product based on a system linking good agricultural practices such as notillage, food processing, transportation, cooking etc, and secondly, develop the economic input-output LCA (EIOLCA) to calculate the monetary spending on a particular product or service that reduces emissions associated with the preparation of a meal. Given the relative lack of LCA data on C sequestration or emission on food production and food service provision, the development of a national data-base will likely present the greatest challenge, both in terms of time and resource investment as well as handling potentially inaccurate data as a consequence of data gap. Additional considerations include: Firstly, there are varying calculations of the emissions from production, processing, delivery over the supply chain, on-site storage, preparation, consumption and disposal of food. Secondly, different levels of product aggregation and geographic relevance in food LCA calculation must ideally be specific to the method of production and relevant to a location; but due to data gap, opportunities are abound for soil scientists to help food producers and food service providers to make approximate comparison between procurement methods to reduce their carbon footprint over time. Thirdly, impact reporting of the magnitude of environmental damage will need careful interpretation of results to be expressed in standardised metrics such as global warming potential (GWP). The paper may be seen as an advance report to the producers and service providers of food on the C footprint. Driven by social responsibility to make changes in food production and procurement, the paper takes soil science used in food production to expand its horizon into playing its anchor role in mitigation GHG emission reduction through soil C sequestration. Some guidance is provided to allow the ordinary citizens to start their own effort to reduce food-related GHG emissions and other impacts thereby contributing their part to slow down global warming and climate change. Though results are preliminary, the encouraging environmentally responsible dietary decision made by the ordinary man in the street to move away from C intensive food production and food service provision will give the country a powerful and new broad-reach tool to complement the purchasing power on their hands to further stimulate efforts to reduce from the food system the GHG emissions and other environmental impacts.