APPLYING BIOSOLIDS: ISSUES FOR VIRGINIA AGRICULTURE

& economics,

& environmental impacts, and

& nuisances.

Prudent consideration of these areas is needed for biosolids applications to be most useful in reducing
costs to everyone (tax payers through their municipal waste water treatment plants, biosolids suppliers,
and farmers). Suppliers must know the regulations governing the use of biosolids and pay careful attention
to the details of each application to safeguard human health and the environment. Productive and
environmentally beneficial use of biosolids requires that farmers know their soils and the nutrient
requirements of the crops they grow. Agricultural application makes productive use of biosolids and is
less costly to society than disposing of them in landfills or through incineration.

Table 1. Land Application of Municipal Biosolids in Virginia

¹ Districts correspond to Virginia Agricultural Statistic Service Crop Reporting
Districts with the exception of “Other.” Other includes data for individual counties
that cannot be identified from the original data because of disclosure problems.

Source: Virginia Department of Health

SOILS

The additional organic matter content from biosolids increases the water holding capacity of the soil.
Such increases in organic matter content are small, but organic matter is so important for soil quality that
even small amounts sometimes make a difference. For example, sufficient amounts of organic matter
may be added through biosolids applications for some soils to have the ability to mitigate the effects of dry
periods during critical growth stages.

Increased organic matter improves soil structure, water infiltration, and water holding capacity. Soil
structure improves because the organic matter causes soil particles to bond together to form loose soil
aggregates. The formation of soil aggregates results in the creation of spaces in the soil. These spaces
allow for more free movement of gases in the soil as well as for more rapid water infiltration. The
combination of soil particle looseness (friability) and space-creating aggregates encourages the creation
of a healthier microenvironment in the soil. As soil quality improves, conditions in the soil profile become
more conducive to the propagation of beneficial worms, predatory insects and spiders, and microorganisms
which further contribute to soil quality. These same features that characterize soil quality and enhance
productivity also decrease surface runoff during and after rainfall, decrease on-site soil erosion and
sediment delivery to receiving water courses and water bodies, and decrease non-point source pollutants
delivered to waterways in general.

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