Soil Health
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fungi have been found to enhance product yields and nutrient content. Plant
growth promoting bacteria have been added to soil with beneficial results
(Brevik et al., 2020; Pidlisnyuk et al., 2020). Endophytic bacteria and fungi
produce enzymes that improve bioremediation of organic contaminants
(Fagnano et al., 2020). Earthworms and nematodes are examples of macroorganisms that enhance nutrient cycling and diversity in soils. Earthworms
improve soil structure and tilth. They are also impacted by pollutants and
their population size is a measure of soil health.
6.5 Improving Soil Health Using Phytotechnology
Phytotechnology with biomass production can have multiple goals including (i) addressing contamination; (ii) improving soil health; (iii) improving
biomass production of a useful product; (iv) adding soil carbon to improve
soil quality and sequester carbon in the soil. Soil amendments may be added
at contaminated sites because they are beneficial for the phytoremediation;
however, it is desirable in selecting amendments to consider all four of the
above goals. Soil amendments can impact pH, microbial populations, nutrient concentrations of N, P, K, and organic carbon, porosity, texture, salinity,
and trace element concentrations.
A recent review by an international group of authors (Palansooriya et al.,
2020) addressed soil amendments for soils containing potentially toxic elements. The authors present three valuable tables with information on a list
of potentially toxic elements (As, Ba, Cd, Co, Cr, Hg, Ni, Mn, Mo, Pb, Sb,
Se, V) including their chemistry in soils; organic soil amendments (animal
waste, biochar, biosolids, compost, plant residues) that are beneficial in contaminated soils; and inorganic soil amendments (clay minerals, coal fly ash,
industrial waste, liming materials, metal oxides, and phosphates) that have
been used. The review includes information on many projects where soil
amendments have been applied to reduce the availability of toxic elements.
Many organic soil amendments have beneficial value for soil health because
the increase in soil organic matter improves soil structure, water-holding
capacity, and nutrient availability. Biomass production is improved, microbial populations are larger, and the ecosystem functions better. The review
includes a comprehensive discussion of research with biochar amendments
in soils with toxic elements, including some information on 29 field studies
reported by O’Connor et al. (2018). The yield with Miscanthus was increased
using biochar in one of the studies. In general contaminant bioavailability
was reduced by adding biochar, but the magnitude of the effect may decrease
when pH decreases over time. Soil amendments have been reported to be
cost-effective and beneficial to soil health and biomass production. When
selecting amendments, it is important to evaluate their composition because
119
fungi have been found to enhance product yields and nutrient content. Plant
growth promoting bacteria have been added to soil with beneficial results
(Brevik et al., 2020; Pidlisnyuk et al., 2020). Endophytic bacteria and fungi
produce enzymes that improve bioremediation of organic contaminants
(Fagnano et al., 2020). Earthworms and nematodes are examples of macroorganisms that enhance nutrient cycling and diversity in soils. Earthworms
improve soil structure and tilth. They are also impacted by pollutants and
their population size is a measure of soil health.
6.5 Improving Soil Health Using Phytotechnology
Phytotechnology with biomass production can have multiple goals including (i) addressing contamination; (ii) improving soil health; (iii) improving
biomass production of a useful product; (iv) adding soil carbon to improve
soil quality and sequester carbon in the soil. Soil amendments may be added
at contaminated sites because they are beneficial for the phytoremediation;
however, it is desirable in selecting amendments to consider all four of the
above goals. Soil amendments can impact pH, microbial populations, nutrient concentrations of N, P, K, and organic carbon, porosity, texture, salinity,
and trace element concentrations.
A recent review by an international group of authors (Palansooriya et al.,
2020) addressed soil amendments for soils containing potentially toxic elements. The authors present three valuable tables with information on a list
of potentially toxic elements (As, Ba, Cd, Co, Cr, Hg, Ni, Mn, Mo, Pb, Sb,
Se, V) including their chemistry in soils; organic soil amendments (animal
waste, biochar, biosolids, compost, plant residues) that are beneficial in contaminated soils; and inorganic soil amendments (clay minerals, coal fly ash,
industrial waste, liming materials, metal oxides, and phosphates) that have
been used. The review includes information on many projects where soil
amendments have been applied to reduce the availability of toxic elements.
Many organic soil amendments have beneficial value for soil health because
the increase in soil organic matter improves soil structure, water-holding
capacity, and nutrient availability. Biomass production is improved, microbial populations are larger, and the ecosystem functions better. The review
includes a comprehensive discussion of research with biochar amendments
in soils with toxic elements, including some information on 29 field studies
reported by O’Connor et al. (2018). The yield with Miscanthus was increased
using biochar in one of the studies. In general contaminant bioavailability
was reduced by adding biochar, but the magnitude of the effect may decrease
when pH decreases over time. Soil amendments have been reported to be
cost-effective and beneficial to soil health and biomass production. When
selecting amendments, it is important to evaluate their composition because