Earthworms: Interactions with management; impacting plant growth?

Full text

(1)Earthworms : Interactions with management; impacting plant growth Reidun Pommeresche, A-K.Løes, S.Hansen and H.Riley NJF, 16.3.2012.

(2) Bioforsk = Norwegian Institute for Agricultural and Environmental research. Holt, Tromsø Svanhovd. Bodø. Tjøtta. Bioforsk - Organic Food and Farming, Tingvoll. Fureneset. Bioforsk Grassland and Landscape, Kvithamar Løken Bioforsk Arable Crops, Apelsvoll. Ullensvang. Ås Særheim. Landvik.

(3) • • • •. 20 ha / farm 4 % farmed area 4 % organically managed 2700 organic farms. Cereals and vegetables.

(4) Milk, meat and grass. 4.

(5) • • • • •. Earthworms in Norway Earthworms in different cropping systems Earthworms and green manure management Earthworms and ploughing Nutrients in earthworm casts.

(6) Table 1 Earthworm species found in arable soil in in scientific studies from 1987, sites ranked by increasing latitude. Xb= dominant species by biomass,. Xn= dominant species by number/density, Xbn = dominant species by both biomass and number/density. X without extra letter = second most common species, x = common species, but found in lower amounts than the dominating species, * = less than three individuals found or less than 1 g m-2. Species/Site, year, latitude. A. A. caliginosa rosea. L. rubellus. L. terrestris. A. chlorotica. *. A. long a Xb. Landvik, 1993 58° °20´ ´N. Xn. x. x. X. Landvik, 1996 Landvik, 2000 Voll, Ås, 1993 59° °40´ ´N. Xb Xb Xbn. x * x. X X x. X x x. x x. X * X. Voll, 1996 Voll , 2000 Apelsvoll, 1994 60° °42´ ´N. Xb X Xn. x x x. * X *. X Xb. *. X X. Apelsvoll, 2004. Xn. X. x. x. Møystad, 2006 60° °47´ ´N. Xn. x. x. Xb. Surnadal1987-89 63° °00´ ´N. Xbn. x. X. Skjetlein,1991 63° °20´ ´N. Xbn. x. Kvithamar, 1993 63° °30´ ´N. Xbn. Kvithamar, 1996 Kvithamar, 2000. *. O. cyaneum. D. rubidus. L. castaneus. Sveistrup et al. 1997. *. Bakken et al. 2006 Bakken et al. 2006 Sveistrup et al. 1997. Bakken et al. 2006 Bakken et al. 2006 Engelstad (pers .obs.). x. *. X. *. x. X. *. Xb. x. X. Xb. x. X. *. Pommersche (pers. obs.) Pommeresche (pers. obs.). *. Hansen and Engelstad 1999 Haraldsen et al. 1994. *. *. *. * x. Reference. X. Sveistrup et al. 1997. Bakken et al. 2006 *. *. Bakken et al. 2006.

(7) Common earthworms in Norwegian agricultural soils. Aporrectodea caliginosa = Grey worm (Field worm), found north to Finnmark 71°N Aporrectodea rosea = Rosy-tipped worm, found north to Tromsø 69° N Lumbricus rubellus = Red worm, found north to Finnmark 71°N Lumbricus terrestris = Dew worm, found north to Tromsø 69° N.

(8)

(9) Earthworm distribution • 30- 350 earthworms/m2 • Grey worm and rosy tipped worm are the dominant species in Norwegian agricultural soils (Aporrectodea caliginosa, A.rosea). • We have also found dew worms (Lumbricus terrestris) in arable soils, not only perennial ley/meadows • Grey worm and red worms (L. rubellus) are found north to Finnmark • Dew and rosy-tipped worms are found north to Tromsø 69°N. • Never found compost worms in field soil (Eisenia fetida, E. andrei).

(10) How to measure effects on/of earthworms?. • individuals / m2 • biomass (g) / m2) • number of channels/ m2 • species composition • decomposition rate of straw • nutrient content in earthworm casts.

(11)

(12) Crop rotation and manuring – effects on earthworms Long term cropping system experiment at Bioforsk, Apelsvoll (A) • • • • • •. With/without animal manure Conventional/ Organic Intensity/portion of grass ley in the crop rotation Chemical plant protection and soil tillage Moraine soil (loam) Started 1987. T. K A. Long term fertilization experiments at Møystad (A) • Different mineral fertilizers vs solid cattle manure • Moraine soil (loam) • Started 1922.

(13) Cropping system experiment at Bioforsk, Apelsvoll (A) – the proportion of ley in the crop rotation..

(14) 1994. Biomass of earthworm. 2004 140 a. 120. a. a. g/m2 (0-25 cm). 100 a. A. 80 AB. 60. AB. AB. AB b. 40. b B. 20 0. NS. 1 (con ar). NS. 2 (opt ar). **. 3 (org ar). *. 4 (opt fo). Cropping system. *. NS. 5 (org fo). 6 (org fo).

(15) Results cropping systems. • Inclusion of leys in the crop rotation increased number of channels, earthworm number and their biomass. • Organic arable had higher density and biomass than conventional • Conventional fodder system had highest density, but no difference in biomass and channels.

(16) Møystad long-term fertilisation trials (A). •7 year crop rotation, one crop each year • 2006 4th year ley, sampling earthworms • Last manuring in 2003 • 4 replicates. T. K A.

(17)

(18) • Positive effect of solid animal manure, even 4 seasons after the last manuring.. ☺.

(19) Green manure management • Effects of different green manure management • Sandy soil (V), clay soil (K). T. K and V A. Værnes aug 2009.

(20) Green manure management.

(21) K, clay soil. Red worm (L. rubellus), living in the upper 5 cm of the soil. Værnes 90. Red worm /m2. 80 70 60 50 40 30 20 10 0. V, sandy soil.

(22) Soil living grey worms (A.caliginosa). Clay soil. Sandy soil.

(23) Soil compaction and tillage, Bioforsk Kvithamar (K) og Apelsvoll (A) • • • •. Ploghing depth (15 vs 25 cm) Tractor weight (2-3 vs 5-7 tonnes) Driving pattern/compaction (3 times normal driving) Nutrient content in earthworm excrements (casts). T. K and V A.

(24) Results • Earthworms were hardly affected • Shallow ploughing (15 cm) was not destructive for the biomass and number of earthworms (grey worms) • More worms when ploughing with a small tractor (5t) than with a heavier one (7t) at Apelsvoll (2006), no effects in the clay soil at Kvithamar.

(25) Lumbricus terrestris (dew worm) eats mostly plant residues, produces nutrient rich manure/cast. Not common in arable soils.. Nutrient content in geophagous earthworm casts in organic cereal production Aporrectodea caliginosa eats mostly soil and dominates the fauna in arable soils. How nutrient rich are their casts?.

(26) Earthworm casts on the soil surface.. How do we collect the casts from field worms that mostly are in the soil?.

(27) Litterbags from two soil types and soil depths • 48 litterbags • 13 cm and 25 cm • May 25, 2005 • Bulk soil • Litterbags up Aug 23 and Oct 18.

(28) Site K, clay soil, 4.9 % SOM. Site A, loamy soil, 3.4 % SOM. K. T A.

(29) Litterbags with barley straw taken up every third week. 2 1.

(30)

(31) Casts and bulk soil • Sorted out cast • 0.5 – 6 g dry weight of casts • Ammoniumacetat-lactate (AL)- extractable nutrients (PAL, KAL, MgAL, NaAL, CaAL) • Tot –N and Tot-C.

(32) Earthworm casts. 20. Soil. mg / 100 g soil (DW). Soil. 15. 2 10. g / 100 g soil (DW). 3. Earthworm casts. 1. 5. 0. 0. P. K. Mg. Na. Ca. Tot-C. Tot-N. Mean of two sites (A, K) and two soil depths (13 and 25 cm).

(33) • The content of tot-N was higher in clay soil (site K) than in loam (site A) = effect of soil type TOT N, 2005 0,40. earthworm casts bulk soil. 0,32. 0,30 0,26. 0,25 0,25 0,22 0,20. 0,21 0,20 0,18 0,16. Not enough casts to analyse. TOT N g /100g soil (DW). 0,35. 0,37. 0,17 0,15. 0,15. 0,10. 0,05. 0,00 0,00. A13cmAUG. A25cmAUG. A13cmOCT. A25cmOCT. site, depth, time. KB13cmOCT. KB25cmOCT.

(34) No effect of soil type on PAL, KAL or MgAL 12,0. earthworm cast. 11,0. bulk soil 9,7. 10,0. P-AL, mg / 100 g SOIL (DW). 9,1 8,2. 8,0. 8,0. 7,6 6,9 6,5 6,1. 6,0. 6,0 5,2. 4,7 4,0. 2,0. 0,0 A13cmAUG. A25cmAUG. A13cmOCT. A25cmOCT. kB13cmOCT. kB25cmOCT.

(35) Dominance of soil eating earthworms • 230 earthworms/m2 (mean three years) • 80 - 85 % (ind.) A.caliginosa, 5 -15 % A. rosea •produce 220 000 kg casts/ha and year (dry w) (0.63 g/day, 153 active days/year, Boström 1988). • 2 290 000 earthworms/ha. 220 t ~ the weight of 32 tractor a 7 tonnes.

(36) Nutrient enrichment = content in cast – content in bulk soil Earthworm casts Soil. 3. 15 2 10. 1. 5. 0. 0. P. K. Mg. Na. Ca. Tot-C. Tot-N. g / 100 g soil (DW). mg / 100 g soil (DW). 20.

(37) Nutrient enrichment in cast (per ha and year) • • • • •. 5.6 kg PAL 8.9 kg KAL 5.3 kg MgAL 144 kg N (tot-N) 2542 kg C (tot- C).

(38) Summing up - casts • The content of “plant available” nutrients and tot-C and tot-N was higher in casts than in bulk soil • No differences between soil depths (13 and 25 cm). • Earthworm casts are valuable sources of plant nutrients • How did the casts got more tot-N? • Earthworm work trough 220 tonnes soil/ha/y.

(39) Acknowledgements:. ☺. • Skilled and enthusiastic Bioforsk colleagues • Funding: Research Council of Norway, The Agricultural Agreement Fund.. Earthworms inside and newly hatched from cocoons (Photo R. Pommeresche).

(40)

Figure

Table 1 Earthworm species found in arable soil in in scientific studies from 1987, sites ranked by increasing latitude

Table 1

Earthworm species found in arable soil in in scientific studies from 1987, sites ranked by increasing latitude p.6

References

Updating...