Anecic earthworms and associated ecosystem services under pressure in a ley-arable crop rotation

Transcription

1 Anecic earthworms and associated ecosystem services under pressure in a ley-arable crop rotation Nick van Eekeren 1, Lydia Bommelé 2, Jan Bokhorst 1, Ton Schouten 3, Dirk Reheul 2 and Lijbert Brussaard 4 1 Louis Bolk Institute, The Netherlands 2 Ghent University, Belgium 3 National Institute for Public Health and the Environment, The Netherlands 4 Wageningen University,The Netherlands

2 Content: Framework research Case study: Ley-arable crop rotation

3 Research part of PhD thesis

4 Main objectives of thesis: 1. To gain insight into the effect of grassland management on soil biota 2. To explore the effect of grassland management on ecosystem services

5 Weight of soil biota under grassland is 5 livestock units

6 Management measures studied: 1.Cropping system (crop rotation) 2.Clover introduction 3.Inorganic and organic fertilizer type 4.N-fertilization level 5.Grass species and species mixture

7 Soil biota studied were: Bacteria Nematodes Micro-athropods Fungi Protozoa EnchytraeidsEarthworms

8 Ecosystem services studied: -Soil structure maintenance -Water regulation -Supply of nutrients -Grassland production

9 Case study: effect of crop rotation on earthworms Experiment established in 1966

10 Four treatments: 1. Permanent grassland since 1966; 2. 3 years temporary grassland in rotation; 3. 3 years temporary arable land in rotation; 4. Permanent arable land since Temporary treatments established by rotavation

11 Parameters measured (amongst others): 1. Earthworms in the autumn 2002, 2003, 2004 (first three years of the 7th rotation); 2. Field water infiltration in autumn 2004.

12 Number of earthworms per m2 Effect on number of earthworms Permanent grassland Temporary grassland Temporary arable Permanent arable

13 Biomass of earthworms (g m -2 ) Effect on earthworm biomass Permanent grass Temporary grass Temporary arable Permanent arable

14 Effect on ecological groups 100% Epigeic 80% 60% Endogeic 40% 20% 0% Permanent grassland Temporary grassland Temporary arable Permanent arable Anecic Endogeic Epigeic Anecic Mechanisme: Stability of feed in permanent grassland

15 mm water h g -1 biomass Especially anecic species increase water 300 infiltration Total Anecic species Earthworm biomass Bouche and Al-Addan, 1997

16 Water infiltration rate (ml water sec -1 ) Effect on water infiltration Permanent grass Temorary grass

17 Conclusions (1) In the grass ley, the abundance of earthworms returned to the level of permanent grassland The anecic species did not recover in the grass ley to the dominance they had in permanent grass. This has consequences for the ecosystem service of water regulation under futures grasslands.

18 Nutrient use efficiency Permanent arable land 200 N 75 N 0 N Temporary arable land 200 N 0 N 75 N

19 Nutrient use efficiency 3 years grass 3 years maize 150 kg N/ha 29 kg N/ha 52 kg N/ha Totally 231 kg N/ha in 3 years Nevens and Reheul, 2002

20 Increase of rainfall in the Netherlands mm of rainfall per year Years Boxel and Cammeraat, 1999

21 Increase number of days with heavy rain Number of days with heavy rain Anonymous, RNMI

22 Conclusions (2) The crop rotation grass maize can be sustainable in terms of efficient nutrient use. However effect of grass maize rotation on anecic earthworms and service of water regulation makes it less sustainable than assumed especially with changing climatic conditions.

23 Future of maize cultivation on dairy farmers Seek for alternative cultivation techniques Possibilities for direct sowing techniques of maize in grassland

24 Effect of direct sowing of maize on earthworms and water infiltration Earthworm biomass g m -2 Epigeic earthworms Endogeic earthworm Anecic earthworm Nicrodrilus Direct sowing Anecic earthworm Lumbricus Rotavation Direct sowing Ploughing Prins et al. 2007

25 Thank you for your attention