The dynamics of Cirsium arvense and Elytrigia repens in long-termed organic crop rotation experiments

Transcription

1 19 th March 2014 PCWC workshop, Alnarp,17-19 March 2014 The dynamics of Cirsium arvense and Elytrigia repens in long-termed organic crop rotation experiments Ilse A. Rasmussen, Bo Melander & Kristian Kristensen Department of Agroecology Aarhus University Research Centre Flakkebjerg DK-4200 Slagelse p TATI RÆ SEN ON

2 Treatments: Crop rotation Entry point / sequence Manuring Catch crop Various control tactics Results from long-termed organic crop rotation experiments at three locations CropSys 2

3 Organic cropping systems at three locations in DK, Foulum 5 % clay, 950 mm 10 % clay, 700 mm 15 % clay, 600 mm Jyndevad Flakkebjerg 3

4 Major perennial weeds in Danish organic farming Common couch grass (Elytrigia repens) Creeping thistle (Cirsium arvense) Coltsfoot (Tussilago farfara) Sow-thistle (Sonchus arvensis) Docks (Rumex spp.) 4

5 Couch grass Creeping thistle 5

6 Cycles Crop rotation O1 Crop rotation O S. b a rle y:le y S. b a rle y:le y Gra ss-clove r Gra ss-clove r S. whea t W. whea t Lu p in Pea:barley S. b a rle y:le y S. b a rle y:le y Gra ss-clove r Gra ss-clove r S. oa ts W. rye Pea:barley Lupin:bean:barley The cropping systems at Jyndevad, a coarse sand S. b a rle y S. b a rle y:le y Pulse crop Gra ss-clove r Pota to Pota to W. wheat W. wheat ± catch crop s, ± m a nure (slurry) 6

7 Couch grass development in rotation O2 on coarse sand Entry 1 Entry CC 35 +CC Number of spikes (m -2 ) GC WW PB SB GC WR LBB SB GC PO WW SB GC WW PB SB GC WR LBB SB GC PO WW SB 7

8 Multiplicative model for calculating the effects of the experimental factors on E. repens proliferation Y t = α t 3 n jk β i ( k ) γ j( k ) = = 1 j 1 k (1) ln( Y t + 0.5) ln( α) + t k= 1 ln( β t 3 i( k ) ) + n jk ln( γ j( k ) ) k= 1 j + E t (2) Y t is the numb e r of sp ike s in the p lot a t tim e t α is the initia l numb e r of sp ike s in the p lot β ik is the e ffe ct of crop type i for ye a r k γ jk is the e ffe ct of cultiva tion ca te gory j for ye a r k n jk is the numb e r of cultiva tions of ca te g ory j in ye a r k E t is a ra ndom e ffe ct of ye a r t. 8

9 Statistical output Effect Estimate SE DDF t-value Probt. Factor Intercept: a Feff < Meff Seff(-CC) < Seff(+CC) < Fab LupG LupC < LBB < OatG OatC Pea/Sba < SbaB < SbaC < Swh < Wry(-CC) Wry(+CC) WwhG < WwhB FertAll

10 Factors that promoted Couch-grass growth No Factors Effects 1 Pulse:barley mixture +736% 2 Spring wheat +501% 3 Winter wheat / grass-clover as the preceding crop +444% 4 Lupin / grass-clover as the preceding crop +397% 5 Oat / cereals as the preceding crop +203% 7 Lupin / cereals as the preceding crop +195% 8 Oat / grass-clover as the preceding crop +158% 9 Spring barley / no cereals as the preceding crop +154% 10 Spring barley / cereals as the preceding crops +124% 11 Winter wheat / spring barley as the preceding crop +103% 12 Winter rye 0% 13 Potatoes 0% 10

11 Factors that reduced the Couch-grass population No Factors Effects 1 Mini summer fallow -62% 2 Stubble cultivation followed by a catch crop -26% 3 Tine cultivation in spring -20% 4 Fertilisation 5 Stubble cultivation without a subsequent catch crop -18% -14% 11

12 Cycles Crop rotation O2 Crop rotation O S. b a rle y:le y Oat Gra ss-clove r W. whea t W. whea t W. whea t 1 Pea:barley Pea:barley S. b a rle y:le y W. wheat Gra ss-clove r Oat W. whea t S. b a rle y Lupin:b a rle y Lu p in 3 The cropping systems at Flakkebjerg, a sandy loam S. b a rle y:le y S. b a rle y Gra ss-clove r Faba bean Pota to Pota to W. whea t W. whea t ± catch crop s, ± m a nure (slurry) 12

13 Proliferation of perennial weeds at Flakkebjerg, main Creeping thistle, at Flakkebjerg Biomass (g m -2 ) Rotation O2 Rotation O

14 Main factors affecting the growth of creeping thistle Crop rotation Entry point, i.e. the specific crop sequence Catch crop Manure Stubble cultivation 14

15 The importance of entry point / crop sequence Creeping thistle in crop rotation O2 Fresh weight (kg plot -1 ) Entry 2 LB SB Entry 3 SB WW LB GC WW GC Year 15

16 Crop effects on creeping thistle Crop Effects Lu p in 8.9 Lupin:b a rle y 2.6 Winte r wheat 2.0 Spring b a rle y

17 C. arvense fresh biomass versus crop biomass in O2 with grass-clover Fertilizer + Fertilizer - Fertilizer + Fertilizer LOG(PW biomass g m -2 ) LOG(Crop biomass g m -2 ) 17

18 C. arvense fresh biomass versus crop biomass in O Fertilizer + Fertilizer - Fertilizer + Fertilizer LOG(PW biomass g m -2 ) LOG(Crop biomass g m -2 ) 18

19 Rodukrudtsbekæ Perennial mpelse weeds Rasmussen I.A., Melander Bo B & Melander Kristensen m.fl. K. Økologi-kongres 2011 Competitive crops and biomass 24 november 19 th March,

20 Competitive crops and catch crops to suppress C. arvense Cirsium arvense number, weight and length at different times during the experiment Crop 2009 C. arvense, # m -2 C. arvense, g m -2 June 2009 July 2010 Nov July 2010 C. arvense, mean length in cm July 2010 Oilseed 14.5 a 49.0 a 21.8 a a 33.2 a rape Fibre 1.3 b 5.3 b 0 a 61.8 a 17.7 a hemp 1 st year 0.3 b 6.5 b 2.3 a a 32.8 a grassclover 2 nd year grassclover 0.1 b 7.3 b 1.1 a 72.1 a 34.8 a Results within the same column with the same letter are not significantly different at P<

21 Conclusions Species specific dynamics Crop suppression important but different responses to crop attributes Crop sequencing crucial to avoid or minimize weak gaps and make room for mechanical control Fertilization and catch crop 21