FEATURE
Biological Soil Quality : Methods of Assessing Soil Quality using Microarthropod Collembola
Initial concepts of soil quality concentrate on the productivity of soils and the properties that contribute towards its productivity ( Carter 1996 ; Bünemann et al . 2018 ). Developing concepts of soil quality has been viewed within a broader understanding of interactions between ecological systems , and how agriculture connects with as well as affects parts of this ecological structure ( Carter 1996 ). Larson and Pierce ( 1994 ) expanded on the concept of soil quality within , as well as beyond agricultural ecosystems , defining it as “ the capacity of a soil to function within its ecosystem boundaries , and interact positively with the environment external to that ecosystem ”.
Edaphic faunae perform a key role in soil ecosystems by their involvement in the regulation of microbial activities , nutrient cycles and most aspects of organic matter decomposition , ultimately influencing soil functioning . Factors which may degrade the nature of soils , such as pollution and land-use intensification , may result in changes in fauna composition and ultimately soil functioning and quality ( Gardi et al 2006 ).
Robyn Nicolay
Current Address : School of Life Sciences , University of KwaZulu-Natal , Pietermaritzburg , South Africa E-mail Address : 220110500 @ stu . ukzn . ac . za
In some cases , specific soil properties are difficult to measure directly , such as soil and ecological processes , and thus indicators , such as indices of edaphic fauna serve as a secondary measure ( Bouma 1989 ). Such indicators should be easily measured , have relatively low sampling error , however showing sensitivity to variation in the management of soils ( Bouma 1989 ). It is , for this reason , biological indicators using soil microarthropods as a benchmark is generally accepted to express the quality of soils that are subject to degradation risk ( Parisi et al . 2005 ).
Methods of evaluating soil quality were developed by Vittorio Parisi and Cristina Menta in the determination of soil quality by means of Qualita Biologica del Suolo ( QBS ) or Biological quality of
Figure 1 : Extracted Collembola specimens exhibiting varying morphological phenology according to their adaptions to the soil environment . Specimen ( a ) indexed as a true Euedaphic type Collembola from the order Poduramorpha , with no discernible ocelli , pigmentation , reduced antenna length , and absent furca . Specimens ( b ) and ( g ) exhibit phenological traits characteristic of hemidaphic type Collembola from the order Poduromorpha , exhibiting prominent pigmentation , ocelli and absent furca . Specimen ( c ) displays phenological type features consistent with epigeic Collembola from the order Symphypleona , displaying clustered ocelli , body segmentation that is not clearly visible and is commonly found in surface soil habitats and leaf litter . Collembolan ( d ) and ( h ) are showing characteristics comparable to order Entomobryomorpha , an epigeic type Collembola with fully developed furca , pigmentation and ocelli . Collembola specimen ( e ), with absent pigmentation , furca , and a present fifth thoracic segment , is consistent with true euedaphic phenology within the order Poduromorpha . Specimen ( f ) shows fully developed furca and obvious pigmentation , phenology consistent with epigeic type Collembola within the order Entomobryomorpha ( Image source : Authors own 2019 ).
11 Grassroots Vol 20 No 4 December 2020