Biosolids have been a very welcome addition to many agricultural areas because it provides the necessary nutrients that are essential in plant growth. It is organic and readily available from wastewater treatment plants which makes biosolids renewable and affordable for farmers to use. There are some drawbacks with biosolids however, in that there is a potential risk of producing excessive nitrates and having phosphorus runoffs which could damage the environment.
A new study by Alan Carpenter and Christian Hanson aims to address this very issue by mixing biosolids with short paper fiber (SPF). Short paper fiber is a by-product of wastewater treatment from paper mills and is composed of wood fiber, clay, and lime. A distinguishing feature of this composition is that it is rich in organic matter such as carbon yet has very low levels of nitrogen and phosphorus content. Because of the low nutrient content, SPF can be applied in large quantities over topsoil to provide increased organic matter without increasing nutrient content. SPF can also increase the water holding capacity of soil tilth even better than biosolids.
SPF, however, has its limitations. Previous studies have discovered that SPF can reduce plant available nitrogen levels in the soil leading to a phenomenon called nitrogen immobilization. This is the result of soil microbes decomposing organic matter in the SPF and consuming plant available nitrogen thereby causing nitrogen deficiencies in the soil. This is the reason why SPF can sometimes be used on agricultural lands with significant nitrate levels to reduce the excessive nitrogen from the soil.
Biosolids, on the other hand, are inherently rich in nitrogen and phosphorus along with some micronutrients. Large volumes of biosolids can cause excessive nitrate levels which may leech into the groundwater affecting its quality. Excessive phosphorus would also cause harm to the environment by inducing algal blooms in bodies of water where the runoff would drain into. It is because of these reasons that biosolids on agricultural lands are not applied in higher volumes.
By combining short paper fiber with biosolids, a good balance can be achieved by taking advantage of the unique characteristics of both materials producing an enhanced organic fertilizer. SPF can be supplied to provide organic material for soil microbes to digest while consuming the rich stores of nitrogen from biosolids to maintain the available nutrient levels needed for plant growth. This avoids contaminating the water supply from excessive levels of nitrogen and phosphorus while also overcoming the problem of nitrogen immobilization that results from using SPF.
A blended topsoil using short paper fiber with biosolids can have a significant effect in boosting soil fertility. This combination is proving to be the best way to revitalize large tracts of agricultural lands without compromising on plant growth and environmental sustainability. It also can also be scaled up in application because it is no longer hobbled by the threats that it may pose to the ecosystem.
If you are a farmer in the Niagara Region and are interested in considering biosolids as a potential application to your fields, please call us on 1 (877) 479-1388. There is no cost for us to apply to the MOE or to spread biosolids on your field. These costs are covered by the Region of Niagara.