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Becoming the Good Soil: A Theological Understanding

Throughout the bible there is reference to the good (fertile) soil (Ezekiel 17:5) and its importance to both our physical and spiritual well-being (Luke 8:5, Mark 4:26-29). In the parable of the good soil Jesus says ”other seeds fell on good soil (in contrast to thorns and rocks) and brought forth grain, some a hundredfold, some sixty, some thirty. Let anyone with ears listen.”(Matthew 13:5-9). Finally concerning God’s commandment to care for others, Jesus calls us to go and bear fruit, fruit that will last (John 15:16).

In the modern world, it behooves us take a broader and more practical view of God’s commandment to keep the garden. When humankind inherited the garden, the soil was “good” and furthermore, there was a natural process for maintaining the fertility. Now, about 40% of the soil around the world is seriously degraded, and scientists predict we will need to feed 9+ billion people by 2050. So as not to perish, humankind must not only care for the garden but also beyond the garden. We must marshal our resources and develop them effectively with sustainability and resilience in mind.

We are called to this mission by our Presiding Bishop, the Most Rev. Michael B. Curry who encourages us to care for our neighbor and ”to go to Galilee”. As members of Nativity one way we perceive that this call to action is to serve as a catalyst – to start and advance the carbon farming work to a level where others with greater knowledge, expertise, and responsibility can carry it forward. We also believe strongly that because of the covenant we all have with God, the greater faith community has 1) a responsibility to engage in and facilitate this process, and 2) to amplify the moral call to create a better future for all life on Earth. And so, an important aspect of our work is to build support within our own congregation as well as to invite members of other faith communities to participate.

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Becoming the Good Soil: Relationships between Food Production, Climate, and Soil

In the endeavor to produce more nutritious food, one of humanities greatest challenges is that many of the steps that might be taken to increase food productivity will have the opposite effect because of climate change. About 25% of the planet’s greenhouse gas (GHG) emissions result from agriculture and deforestation (1), and as the planet warms, crop yields are decreasing (2). The major sources of the three main biogenic GHGs from agriculture and land-use change are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). To avoid the most serious consequences of climate change, emissions of these gases from burning fossil fuels and engaging in agriculture must be reduced, and in addition, excess carbon needs to be withdrawn from the atmosphere and sequestered into the soil.

1) Paustian, et al. Climate Smart Soils, Nature, 532, 49-57 (2016).
2) Premanandh, J, Factors affecting food security and contribution of modern technologies in food sustainability, J. Sci Food Agric 91:2707-2714 (2011).

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Becoming the Good Soil: To Avoid the Most Serious Consequences of Climate Change We Must Have “Negative Emissions”

The growth rate of climate forcing due to human-caused GHGs increased over 20 % in the past decade mainly due to resurging growth of atmospheric CH4, thus making it increasingly difficult to achieve targets such as limiting global warming to 1.5 °C or reducing atmospheric CO2 below 350 ppm. To achieve such targets now require negative emissions, i.e., extraction of CO2 from the atmosphere. If rapid phasedown of fossil fuel emissions begins soon, most of the necessary CO2 extraction can take place via improved agricultural and forestry practices, including steps to improve soil fertility by increasing its carbon content and reforestation (1).

1) Hansen, J, et al, Young People’s Burden: Requirement of Negative CO2 Emissions, Earth Syst. Dynam. Discuss., submitted for Publication (2016)

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Becoming the Good Soil: Role of Soil in Carbon Sequestration

Soils constitute the largest terrestrial organic C pool (~1,500 petagrams* (Pg, 1015 grams ) C to a depth of 1 m; 2,400 Pg C to 2 m depth), which is three times the amount of CO2 currently in the atmosphere (~830 Pg C) and 240 times the current annual fossil fuel emissions (~10 Pg). Thus, increasing net soil C storage by even a few per cent represents a substantial C sink potential (1).
Soil C sequestration is one of a few strategies that could be applied in large scales and potentially at low cost; as an example, the French government has proposed to increase soil C concentration in a large portion of agricultural soils globally by 0.4% per year in conjunction with the Conference of the Parties to the UN Framework Convention on Climate Change (UNFCCC) negotiations in December 2015. This would produce a C sink increase of 1.2 Pg of C per year (1).

1) Paustian, et al. Climate Smart Soils, Nature, 532, 49-57 (2016).

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Becoming the Good Soil: Soil Carbon Sequestration Potential of US Croplands and Grasslands

The first comprehensive assessments of potential soil C sequestration on managed lands for the United States were led by researchers from USDA’s Natural Resources Conservation Service (NRCS) and Agricultural Research Service (ARS) and the Carbon Management and Sequestration Center of The Ohio State University. These syntheses focused on the potential of US soils to sequester carbon with adoption of best management practices under different land uses. Subsequently, more detailed assessments of the technical potential for carbon sequestration at global (1) and US scales generally support these earlier estimates of a significant soil C sink potential, on the order of hundreds of teragrams (1 Tg, equals 1012 (one trillion) grams or 1 million metric tonnes) per year in the United States (45 to 98 Tg for cropland and 13 to 70 Tg for grazing land) and roughly an order of magnitude higher globally (2).

1) Intergovernment Panel on Climate change, Third Assessment Report, 2001.
2) Chambers, A, et al, Soil carbon sequestration potential of US croplands and grasslands: Implementing the 4 per Thousand Initiative, J Soil and Water Conservation, 71, 68A-74A (2016).

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Becoming the Good Soil: Increasing Soil Carbon Will Increase Crop Yields

Increasing soil carbon will increase total soil organic matter (SOM), which is the very foundation for healthy and productive soils (1). Organic farmers often judge and monitor soil health based on the amount of organic matter in each farm field. Active soil organic matter refers to a diverse mix of living and dead organic materials near the soil surface that turn over or recycle every one to two years. Active organic matter serves as a biological pool of the major plant nutrients. The balance between the decay and renewal processes in this biological pool is very complex and sensitive. The populations of microorganisms that make up the biological pool are the driving forces in soil nutrient dynamics. Together they also play a key role in building a soil structure that both retains and freely exchanges nutrients and water—a soil where plant roots thrive (2). Maintaining the concentration of SOM above a threshold level is essential for maintaining soil health, productivity, and sustainability. Loss of SOM leads to degradation of soil structure, reduction in soil water-holding capacity, and exacerbates climatic extremes. Thus, judicious management of the soil carbon pool is necessary (1).

1) Magdoff, F and Van ES, H, Building Soils for Better Crops, Sustainable Soil Management, SARE Outreach Publications, Brentwood, Md, 2009.
2) Keith R. Baldwin, Crop Rotations on Organic Farms, North Carolina Cooperative Extension Service (2006), www.cefs.ncsu.edu.

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Becoming the Good Soil: Supplementation of Cropland with Compost Increases Productivity

A review of the use of organic supplements to cropland indicated that application of long-lasting organic amendments increased organic carbon by up to 90% versus unfertilized soil, and up to 100% versus chemical fertilizer treatments. Furthermore, regular addition of organic residues, particularly composted ones, increased soil physical fertility, mainly by improving aggregate stability and decreasing soil bulk density. The best agronomic performance was obtained with the highest rates and frequency of applications. Crop yields increased by up to 250% after long-term applications of high rates of municipal solid waste compost (1).
Compost is the end of product of a controlled aerobic decomposition of organic wastes (such as yard waste, food waste, animal manures, and other materials that come from recently living organisms). Compost has readily available and other slow-releasing plant nutrients, as well as a high organic matter content, which helps to feed the microbes in charge of creating a well-rounded environment for life to flourish.
The reason that compost is so effective in increasing crop yields is that compost is more slowly decomposed compared to fresh plant residues, with composts typically having mean residence times several times greater than un-composted organic matter (2).
A single application of composted green waste to California rangeland significantly increased forage production from 40 to 70% over three years (3).
Compost has also been shown to increase yields for field crops. In a six year field experiment studying the effect of farm compost amendment on a crop rotation of potato, fodder beet, forage maize, and Brussels sprouts demonstrated that farm compost increased soil quality and crop yields establishing a causal relationship between soil quality and crop production (4).
Finally, it has been estimated that an increase in the SOC pool within the root zone by 1 t C/ha/year could enhance food production in developing countries by 30 to 50 Mt/year including 24 to 40 Mt/year of cereal and legumes, and 6 to 10 Mt/ year of roots and tubers (4).

1) Diacono M, and Montemurro, F, Long-term effects of organic amendments on soil fertility. A review, Agron. Sustain. Dev. 30, 401–422 (2010).
2) Paustian, et al. Climate Smart Soils, Nature, 532, 49-57 (2016).
3) Ryals, R., and W. L. Silver. 2013. Effects of organic matter amendments on net primary productivity and greenhouse gas emissions in annual grassland ecosystems. Ecological Applications 23:46-59.
4) D’Hose, et al. The positive relationship between soil quality and crop production, Applied Soil Ecology 75, 189– 198 (2014).

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Becoming the Good Soil: Other Ways That Compost Helps Mitigate Climate Change

To make compost, organic materials are necessary, like yard waste, food waste, wastewater treatment plant residuals, animal manures, or others. Currently, some organic wastes are finding their way to the landfill, where they decompose anaerobically (without oxygen) and methane is emitted—a greenhouse gas contributing to climate change. Landfills contribute 20% of the total methane emissions generated in the US (https://www.epa.gov/ghgemissions/overview-greenhouse-gases). The EPA estimated that in 2014 the trash contained approximately 22% food by weight (https://www.epa.gov/smm/advancing-sustainable-materials-management-facts-and-figures-report ). In North Carolina alone, it is estimated that just over 8% of the excess food generated is recovered from the landfill through composting, anaerobic digestion, food donations, and animal feeding (NCDEQ 2012 and 2016 reports — http://deq.nc.gov/conservation/recycling/composting/composting-resources). Composting itself produces carbon dioxide as a byproduct of the respiration of the composting microorganisms, and it could produce methane and nitrous oxide if the pile is not managed correctly; however, when compared to the traditional method of organic waste disposal—landfilling—composting is regarded as a way to avoid the generation of methane (http://faculty.washington.edu/slb/docs/CCAR_Composting_issue_paper.pdf). Therefore, just the act of diverting organic waste from the landfill can prevent significant quantities of methane from being generated, helping to mitigate climate change in its own way.

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Caring for Our Common Home: Composting (updated blog from December 28, 2015)

By composting at home and the church, we can: 1) reduce the amount of garbage we generate, 2) create valuable compost for home and church gardens, and 3) decrease our carbon footprints by sequestering carbon in the soil.
As part of our goal to achieve “zero waste” on our church campus, Nativity uses a composting service, Food FWD (http://foodfwdnc.com/), which distributes sustainable and compostable single-use items like cups and plates, utensils, take out boxes, and other products for people looking to use earth-friendly items. FWD has provided the church with two collection bins, which they pick up weekly.
Also on our church campus, we have two compost bins just inside the fence of the Nativity Community Garden (NCG). The finished compost is used in the garden. Parishioners are welcome to add compostable materials from their homes to the bins in the NCG). Please only add new raw material to the right hand bin. For what to compost and what not to compost, see lists below.
Another option to keep compostable material out of the landfill is to sign up for a household composting service like CompostNow (http://compostnow.org/).

What to Compost:
Kitchen greens, fruit scraps, chewing gum, vegetable scraps, house plant trimmings, coffee grounds, rice, pasta, eggshells, tea bags, fresh flowers (not woody), plant trimmings (not woody), leaves (not as thick matt), coffee filters, stale bread, paper napkins, paper towels, dryer lint (not containing synthetic fibers), hair, fur from brushed animals.

What not to Compost:
Meat, fish, bones, dairy products, oils and fats, sauces, ashes, pet waste, diseased plants, weeds (especially with seeds), grass clippings.