How Composting Can Increase Crop Yields and Save Water

Daphna Nissenbaum, CEO, co-founder, TIPA Corp.

The “California Drought” is affecting a lot more than California; it's actually a result of an unprecedented 23-year drought that is slowly but surely drying up the Colorado River, the main water source for the entire Southwest. To preserve water, California and other western US states have instituted restrictions on household and business water use.

But in order to really save water, states like California need to focus on agricultural water use. According to state officials, 80 percent of all water in California is used for agriculture. In addition to affecting the lives of tens of millions, the lack of water is affecting food prices – and supplies, with California alone supplying 15 percent of US agricultural produce. But the heavy use of water by farmers provides a great opportunity to conserve. Even small improvements in agricultural water efficiency can be significant, according to state officials.

One of those small improvements -- that could have far-reaching consequences – entails a greater usage of organic compost in soil. According to experts, a 5 percent increase in organic composting material in soil quadruples its water-holding capacity, meaning less need for irrigation or other external water sources.

Composting is already helping some California farmers survive the drought. But wider application of composting could have a significant effect on extending the water supply. Less water required for farming means less taken out from the rivers and aquifers, improving the water economy throughout the West.

The science on this is solid; organic compost retains water, and if that compost is rototilled into dry ground, it provides a water source for plants and vegetables growing in that ground. Several comprehensive studies on organic waste deposited in different types of soil showed that this compost provided vegetables with as much as two weeks of water even in dry conditions; compost-enhanced soil held nitrates better, even after heavy rains, and yields of crops from such soil were significantly higher than from soil treated with fertilizer.

In addition to saving water, increased use of compost in agriculture, and the composting process itself is important to mitigating climate change, which has led to the increasing severity of droughts, a trend that is expected to worsen. Treating soil with organic waste, which contains high amounts of carbon, also combats climate change by removing planet-warming carbon dioxide from the atmosphere. A 0.4 percent annual increase in the amount of carbon in the world’s soil can stop the rise of  carbon dioxide levels in the atmosphere.

Producing this compost from food scraps, yard waste and some types of compostable packaging, also helps fight climate change by reducing the methane that these organic materials create when disposed of in landfills. This organic matter in landfills in the United States is responsible for 14.5 percent of total human-produced methane emissions, the third largest source after the fossil fuel and animal agriculture sectors. In contrast, composting this waste, an oxygen-rich process, does not produce these emissions. 

If anything is holding California farmers back from wider production and usage of organic compost, it is supply – and state regulation. Both of those issues will hopefully be resolved by the Short-Lived Climate Pollutant Reduction law (SB 1383), which requires jurisdictions to provide facilities for composting of food waste. The law requires that at least 20% of food be “reclaimed” by 2025, while the rest be composted – which will significantly increase the supply of compost available to farmers.

Giving further hope to make this law a real gamechanger, efforts are underway to develop and obtain more funding for food waste collection programs, making sure that food gets to compost facilities, and that local jurisdictions and towns are not overly burned by these expenses. Some of this additional money could also be used to subsidize transportation of compost to farms, as well for education efforts to ensure that farmers take advantage of the compost bounty that will soon be available. As it stands now, the law does not include a provision for transporting that compost to farms – and transportation of compost from the coastal urban centers to the rich farmlands of the Central Valley and other growing areas could make this newly-available compost too expensive for many farmers. 

Those subsidies, if they materialize, will likely make a big difference in how many farmers adopt composting; the more economically feasible, the more farmers will purchase compost in order to help reduce their water usage. With the right policies, California and other western states can significantly use composting to reduce their usage of water – allowing for the repair of the region's water economy, and ensuring the viability of the water infrastructure and supply for many years to come.

Daphna Nissenbaum is the CEO and co-founder of TIPA Corp.

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