Consideration of risk management practices in regulatory risk assessments: evaluation of field trials with micro-dams to reduce pesticide transport via surface runoff and soil erosion

Environmental Sciences Europe

Table 2 Effects of micro-dams in potato cropping and distinct strategies in maize cultivation on runoff quantities, erosion, plant protection product (PPP) loads and curve numbers (CN; means), as means with standard deviations, 10th percentiles, and ranges; n.a.: not applicable

	Potatoes						Maize
	Olivier et al. 29]	Goffart et al. [21]^a,g		Aurbacher et al. [6]^b	Areas [3]^c	Areas [4]	CIPF [7]^d,e	UCL [41]^d,e
	Olivier et al. 29]	2009	2010	Aurbacher et al. [6]^b	Areas [3]^c	Areas [4]	CIPF [7]^d,e	UCL [41]^d,e
Runoff reduction	86% (± 14%) 10th pt.: 82% (47%–100%)	79% (± 19%), 10th pt.: 61% (53%–98%)		98%	81% (69%–93%)	84%	53% (± 24%) 36%, 70%	48% (± 6%) 52%, 44%
Runoff change	− 86% (± 7%), 10th percentile: − 80%						− 51% (± 9%), 10th percentile: − 45%
Erosion reduction	85% (± 35%) 10th pt.: 67% (0%–100%)	88% (± 17%) 10th pt.: 71% (58%–100%)		97%	n.a.	n.a.	67% (± 15%) 57%, 78%	76% (± 2%) 77%, 74%
Erosion change	− 90% (± 6%), 10th percentile: − 86%						− 71% (± 6%), 10th percentile: − 68%
PPP reduction^f	n = 4, 91% (± 5%) 10th pt.: 86% (87%–96%)	n = 5, 84% (± 20%) 10th pt.: 62% (56%–100%)		n.a.	n.a.	n.a.	n = 4.50% (± 17%) 38%, 62%	n = 1.41% (± 7%),36%, 46%
PPP change	− 88% (± 4%), 10th percentile: − 85%						− 46% (± 12%), 10th percentile: − 39%
CN untreated	83	–	–	75	92	95	68	78
CN treated	73	–	–	39	73	78	67/64^d Mean: 65	75/73^d Mean: 74
→CN reduction	10 (12%)	–	–	36 (48%)	19 (21%)	17 (18%)	3 (4%)	4 (5%)
CN change^g	Mean CN untreated/treated: 86/66 (reduction: 21 ± 11; 10th percentile: 12) (− 25% (± 16%), 10th percentile: − 14%)						− 5% (± 0.7%)

^a%-tal reductions in runoff, erosion and PPP reduction given as mean values of 5 trials over the 2 years
^bMean values over the 35 reported trials available only
^cRunoff was generated “delayed” in this trial, both CN and %-tal runoff reduction based on the 2 measurements after 40 mm of artificial rain
^dTwo distinct techniques were applied: disc and drum plough
^eRunoff, erosion, and PPP reduction percentages: all evaluations are given as mean values over the distinct treatments
^fAverage reductions of the sums of PPP solved in runoff water and sorbed to the sediment; over all PPP applied
^gDue to the conceptual difference of one reported value for a complete season, CN from Goffart et al. [21] were not included here (see Additional file 1: Table S3 for details)