Is Composting Really Worth It?

Adding compost to your soil can improve soil health and fertility, but too much compost can harm your plants and the environment. Growers have faced problems in recent years due to practices such as deep compost mulch, adding more compost to high tunnels, and growing in raised beds with pure compost. 

According to Natalie Hoidal in, “How to correct problems caused by using too much compost and manure” Hoidal research explains, Agricultural soils with excessive compost applications, particularly manure, tend to develop high levels of nutrients including ammonium, calcium, magnesium, potassium, and sodium. Moreover, these soils can contain high levels of bicarbonates, carbonates, and hydroxyls. Deficiencies can result from too much of any nutrient.

Calcium, magnesium and potassium can be inhibited if the soil becomes too acidic. Soil alkalinity is associated with high calcium, magnesium, and potassium concentrations. High alkaline soils tend to be high in pH, a measure of how acidic or basic the soil is. Many nutrients become less available in highly alkaline soils. As a result plants may exhibit nutrient deficiencies despite having plenty of nutrients in the soil, due to the decreased availability of these nutrients. When growing in a tunnel, soluble salts can build up in the soil, causing salt toxicity. Manure is generally high in salts and ammoniacal nitrogen, and is not recommended for growing in high tunnels.

The FFTC explained, in the article “Benefits and Drawbacks of Composting” that the product is expensive to transport because it is large and heavy. Compost typically cannot quickly cover the nutrient needs of crops due to its low nutrient value compared to chemical fertilizers and sluggish rate of nutrient release, which leads to some nutrient deficit. Comparatively to chemical fertilizers, compost has a much more varied nutrient makeup. Concerns about probable concentrations of heavy metals and other pollutants in compost, especially mixed municipal solid wastes, may exist among agricultural users. When compost is applied on food crops, contamination risk becomes a significant problem. Composts applied to agricultural soils for an extended period of time or in large quantities have been proven to cause salt, nutrient, or heavy metal buildup and may be harmful to plant development, soil organisms, water quality, and animal and human health.

Given the numerous benefits that compost provides to plants and soils, it is difficult to accept that its use can cause plant damage. Although uncommon, it is possible, especially if the compost is not properly prepared or is not suited to the application. If the compost is used at high rates or with sensitive plants, such as seedlings, the risk of damage increases. When compost harms plants, our first instinct is to blame a contaminant, such as a herbicide. Other factors, however, are more likely to be at work.

High salinity may be the most common cause of composting issues. Plants obtain nutrients from soils in the form of dissolved salts, but a concentration that is too high harms plant roots. Harry Hoitink states, in the article, “Can Compost Damage Plants?” “Salt damage causes the plant to wilt quickly and the leaves to yellow.” High salinity weakens plants and frequently causes root rot, particularly from Phytophthora and Pythium. Soybeans, rhododendrons, and a variety of other plants may be harmed. Although some salts are more harmful than others, the total salt concentration is critical. Because the sensitivity of plants to salinity varies greatly. Although ammonia is a source of nitrogen for plants, high concentrations are toxic. If exposed to high levels, affected plants die overnight. Burning on the margins of young leaves is common at lower levels. Root tips on less sensitive plants turn brown. Azaleas are excellent indicator plants. Composts with a high nitrogen content pose the greatest risk of ammonia toxicity, especially if the nitrogen is in an available form.

The main reason for organic farming is to better the environment. Farmers and gardeners use the practice of composting as a huge part in improving the problems farmers and society are affected by. Robert Pavlis, throughout the article, “Does Composting Contribute to Climate Change?” states, “A compost pile will produce CO2, which increases the CO2 in the air, which in turn results in the warming of our planet.” If a compost pile isn’t aerated, it can emit methane, a harmful greenhouse gas. Landfills also emit methane, so they’re not good either. Carbon is an element found in organic matter. When organic matter breaks down, it releases carbon dioxide (CO2). This happens because bacteria break down the organic matter. Bacteria release CO2 as they do this. The amount of CO2 released depends on how fast the bacteria can break down the organic matter and how much oxygen is around.

References

How to correct problems caused by using too much compost and manure. (n.d.). 

Extension.umn.edu. https://extension.umn.edu/nutrient-management- specialty-

crops/correct-too-much-compost-and-manure

Benefits and Drawbacks of Composting. (n.d.). Food and Fertilizer Technology Center. 

  Retrieved November 26, 2022, from https://www.fftc.org.tw/en/publications/

  detail /1431 #:~:text=Long%2Dterm%20and%2For%20heavy

Can Compost Damage Plants? | Whatcom County | Washington State University. 

  (n.d.). Whatcom County. Retrieved November 26, 2022, from 

Can Compost Damage Plants?

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Pavlis, R. (2019, December 11). Does Composting Contribute to Climate Change? 

  Garden Myths. https://www.gardenmyths.com/composting-climate- 

 change/#:~:text=In%20simple%20terms%2C%20a%20compost