Ecological properties of earthworm burrows in an organically managed grass-clover system

Transcription

1 AARHUS UNIVERSITY, FACULTY OF SCIENCE AND TECHNOLOGY Ecologicl properties of erthworm burrows in n orgniclly mnged grss-clover system Pul Henning Krogh 1, Mthieu Lmndé 2, Jørgen Eriksen 2, Mrtin Holmstrup 1 phk@dmu.dk 1 DEPARTMENT OF BIOSCIENCE 2 DEPARTMENT OF AGROECOLOGY

2 Digging whole

3 Vcuum clening the surfce

4 Delineting burrows

5 Burrow distribution redy for imge nlysis

6 Totl erthworm bundnce nd biomss bc 1. yer cutting Abundnce, m -2 b 3. yer grzing + cttle slurry 3. yer cutting3. yer cutting cttle slurry Biomss, W.W. m -2 Wet weight, m -2 c Winter rye 250 g erthworm biomss m -2 = 2500 kg h b 500 kg yer cutting 3. yer grzing 3. yer cutting 3. yer cutting cttle slurry Winter rye

7 Biomss of two life-forms b A. tubercult yer cutting b 1. yer cutting c 3. yer grzing 3. yer grzing bc 3. yer cutting A. long 3. yer cutting bc 3. yer cutting cttle slurry 3. yer cutting cttle slurry Winter rye b Winter rye

8 Influence of gronomic elements of clover-grss cropping Species Slurry Clovergrss ge Grzing Annuls A. tubercult 0 + Endogeic A. rose 0 + Anecic L. terrestris A. long + + 0

9 Burrow dimeter size distribution Grzing reduces mcropore density t 40 cm Few lrge (<<10) mcropores t 1 m in nnul crops But even few could provide high wter-flow

10 Correltions between burrows nd erthworm species - summry Anecic species nd A. rose re significntly positively correlted with burrows The endogeic A. tubercult ws consequently negtively correlted to mcropores No correltion between smll mcropores, 1 mm Ø, nd erthworms

11 Addition of bromide to the soil simultion of hevy rinfll Irrigtion for one hour of 18.5 mm bromide solution (moderte-hevy rinfll) Bromide is nlysed down the soil profile fter 24 hours Lmndé et l. (2010). "Cttle trmpling reduces the risk of nitrte leching in orgnic diry rottions." ICROFS news 2010(2): 5-7.

12 Lmndé et l. (2010). "Cttle trmpling reduces the risk of nitrte leching in orgnic diry rottions." ICROFS news 2010(2): 5-7. Wter flow through the soil

13 Burrow sptil distribution s mde by endogeic nd necic erthworms Lmndé et l. (2010). "Cttle trmpling reduces the risk of nitrte leching in orgnic diry rottions." ICROFS news 2010(2): 5-7.

14 Schemtic presenttion of wter flow when cttle trmpling hs reduced top soil porosity Lmndé et l. (2010). "Cttle trmpling reduces the risk of nitrte leching in orgnic diry rottions." ICROFS news 2010(2): 5-7.

15 Results of bromide ppliction Wter velocity ws higher with grzing Suggestion: due to less number of mcropores wter ws flowing to the lrge mcropores leding to higher velocity Lmndé et l. (2010). "Cttle trmpling reduces the risk of nitrte leching in orgnic diry rottions." ICROFS news 2010(2): 5-7.

16 Conclusions All min element of clover-grss cropping ffects erthworm communities s demonstrted just by our study: Fertiliztion Crop ge Grzing Agroecologicl consequences of erthworm burrows: Leching depends on the mcropore density nd size distribution Wter cn by-pss the bulk soil through lrge mcropores nd void leching of nitrte

17 New reserch ctivities EcoFINDERS - EU FP7 Including erthworm ecology nd burrow distributions in the JULES (Joint UK Lnd Environment Simultor) hydrologicl model including runoff nd infiltrtion dynmics PESTPORE - Dnish EPA The occurrence nd influence of deep biopores on pesticide leching from lnd surfce to chemiclly reduced ground wter in glcil clyey till