Increasing level of liquid pig manure reduces Eisenia andrei and Enchytraeus crypticus reproduction in subtropical soils

Abstract

Wastes generated in pig production are widely used as agricultural fertilizers. nevertheless, such form of disposal supplies large amounts of waste in soils annually and can cause environmental pollution. the ecological risk of this practice to soil organisms has received little attention. ecotoxicological tests are used to evaluate the toxicity of contaminants added to the soil biota. the aimed to evaluate the effect of liquid pig manure (LPM) on the reproduction of Eisenia andrei and Enchytraeus crypticus when applied in natural soils. LPM doses caused effects on earthworm reproduction in both soils, with ec 50 of 112 and 150 m 3 ha −1 in the Entisol and Nitosol, respectively. On enchytraeids, LPM had bigger effects, leading to EC 50 of 17.7 and 45.0 m 3 ha −1 in the entisol and nitosol, respectively. the results emphasize the importance to consider the ecological risks of LPM of conducting studies with natural soils and edaphic fauna as indicators. Brazil occupies the fourth position among the main global pig meat producers 1 and, to achieve such position, it employs a production system with high technological level and high concentration of animals in the production units. In turn, this alternative of production leads to accumulation of large volumes of pig manure per unit of area, which has been used as agricultural fertilizer, since it is an important source of N and P to agricultural soils 2. Soil addition of high amounts of liquid pig manure in producing regions could exceed the support capacity of the soils, which can lead to environmental damages. Prolonged utilization or large volumes of pig manure for fertilization can cause accumulation of nutrients such as P, K, Cu and Zn, especially in the 0-5 cm layer 3 ; however, the norms of application do not consider the possible effects on important groups of soil organisms such as oligochaetes, which perform relevant functions in the soil, for example nutrient cycling. Therefore, the establishment of doses to be applied should also consider the possible deleterious effects on soil biota. The magnitude of LPM application effects on survival and reproduction of edaphic organisms can be measured by ecotoxicological tests which are internationally used to evaluate toxic effects of various substances and compounds on living organisms. These tests can be used as soil quality indicators and present themselves as parameters to ecological risk analyses. Hence, organism's responses to contaminants, obtained in ecotoxicological tests, help in the determination of safe concentrations for their use in the environment. Earthworms (Eisenia andrei-Bouché) and enchytraeids (Enchytraeus crypticus) are good indicator organisms, because they play a key role in the provision of regulatory ecosystem services and are proven to be sensitive to the presence of certain pollutants in the soil. There are many studies in the literature evaluating the magnitude of the effects of metals, drugs, excessive nutrients and other substances on the survival, reproduction, bioaccumulation and pro...

Manure management and soil biodiversity: Towards more sustainable food systems in the EU

“…In France, zinc in manure contributed to 78% of overall zinc contamination in soils (Belon et al, 2012). Testing various doses of pig manure on earthworms (ranging 0 to 300 t ha − 1 ) and enchytraeids (ranging 0 to 100 t ha − 1 ), Segat et al (2020) found increasing doses to reduce juveniles of both groups significantly. Another study tested the effects of a single application of 20, 50 and 150 t ha − 1 of pig manure on soil fauna, whereby the highest amount altered soil fauna composition significantly, increasing insect larvae, dipterans and mites while decreasing ants, collembolans, earthworms and enchytraeids (Segat et al, 2019).…”

“…While heavy metals cannot be removed by treatments, antibiotics (Zhang et al, 2014a), antibiotic-resistant genes (Sengeløv et al, 2003) and hormones (Kjaer et al, 2007) can be reduced via certain treatment. Contaminants in slurry were found toxic to earthworms and enchytraeids (Segat et al, 2019;Segat et al, 2020) and collembolans in subtropical soils (Segat et al, 2020). Walsh et al (2012) found slurry to reduce microbial growth and fungal diversity.…”

Relationships among Physicochemical, Microbiological, and Parasitological Parameters, Ecotoxicity, and Biochemical Methane Potential of Pig Slurry

“…Both seed germination and root elongation and Daphnia magna immobilization toxicity tests were successfully used for evaluating whole effluent toxicity [18,19]. Therefore, the combined use of toxicity tests and physicochemical parameters allows the integral assessment of the raw manure before disposal [19][20][21][22].…”