|Main authors:||Luuk Fleskens, Coen Ritsema, Zhanguo Bai, Violette Geissen, Jorge Mendes de Jesus, Vera da Silva, Aleid Teeuwen, Xiaomei Yang|
|iSQAPERiS editor:||Jane Brandt|
|Source document:||Fleskens, L et al. (2020) Tested and validated final version of SQAPP. iSQAPER Project Deliverable 4.2, 143 pp|
Empirical cumulative probability density curves were produced for each soil quality indicator in every pedo-climatic zone. The density curves were based on empirical probability density histograms with 256 bands between the lowest and highest value of each soil quality indicator in every pedo-climatic zone. The cumulative probability (%) corresponding to the actual soil quality indicator value in a given location, was then considered to be the relative performance of that soil quality indicator at that location. The potential improvement of that soil quality indicator at that location was then considered to be the absolute cumulative probability corresponding to the best attainable value minus the relative performance of that indicator (e.g. 7%, Figure 18) of the soil quality indicator (Table 12).
The overall soil quality improvement potential was then considered to be the average improvement potential of all soil quality indicators. The number of soil quality indicators considered was dependant on data availability. Some soil quality indicators, for instance, were only available for countries within the European Union.
Table 12. Soil quality indicators and optimums used to define relative improvement potential.
References: (a) Panagos et al. (2015), (b) Borrelli et al. (2017), (c) Shangguan et al. (2014), (d) Hengl et al. (2017), (e) Lado et al. (2008), (f) Nicholsen & Chambers (2008), (g) Orgiazzi et al. (2016).
Figure 19 provides an overview of the threshold values for soil threat indicators based on »Calculating the soil quality index in SQAPP. For the soil threat of risk of pesticide contamination, two scores were considered (Figure 20):
- of the total number of each type of pesticide ranked from low to high, the PEC score of the 0.25 percentile pesticide was considered the upper boundary for a low risk (green). The 0.75 percentile pesticide constitutes the lower boundary for high risk (red). Intermediate PEC scores are classified as moderate (orange).
- The number of pesticides applied was also considered as a factor influencing pesticide contamination risk, as cocktails of pesticides may present additional threats to the environment. Five pesticides was considered the upper threshold for a low threat (green) and ten pesticides the maximum for a moderate threat (orange). If more than ten pesticides are applied the PEC indicator is classified as high (red).
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