Blas%ng weed compe%%on away! Sam Wortman Assistant Professor Department of Crop Sciences University of Illinois

Transcription

1 Blas%ng weed compe%%on away! Sam Wortman Assistant Professor Department of Crop Sciences University of Illinois

2 Weed management in vegetable crops can be difficult Fewer registered herbicides Herbicide resistance Consumer demand for pes%cide- free and cer%fied organic produce is growing Hand- weeding is expensive and difficult to source

3 There are no silver bullets in non- chemical weed management Need to employ many limle hammers How can we control weeds that escape the crosshairs of cover crops, rota%on, %llage, or even herbicides?

4 Air- propelled abrasive grits, weed blas%ng, may serve as another li#le hammer

5 Results of greenhouse blas%ng project

6 Ini%al studies inspired field- scale weed blaster

7 Designs based on prototypes by Frank Forcella and SDSU Hand- held applicator ~ $3,000 Tractor- mounted 4- row applicator ~$20,000

8 Field trials conducted in 2013 and 2014 at Urbana, IL 2013 fresh market tomato Diversified organic vegetables previous 4 years 2014 green bell pepper Conven%onal corn soy rota%on previous 3 years

9 Abrasive grits applied between 1 and 4x Weeds between VC and V3 stage Grits: corn cob, walnut shells, soybean meal, greensand (2013)

10 Air- propelled abrasive grits applied within crop hole

11 Weed density 37 days aaer 1 st applica%on in tomato 16 Weed density (plants plot -1 ) Broadleaves Grasses No. of applications ü Blas%ng reduced the density of both broadleaf and grass weeds by as much as 83.2 and 60.1%, respec%vely

12 End- of- season weed biomass in tomato Aboveground weed biomass (kg plot -1 ) Weedy check Treated ü Blas%ng, regardless of media or rate, reduced weed biomass by 66% rela%ve to the weedy check

13 Treatment 4x Walnut shells differences were obvious in the field Untreated control

14 Total tomato yield (marketable and non- marketable) 25 Total tomato yield (tons acre -1 ) b a ab a a a 0 Weedy check Weed free check Corn cob grit Greensand Soybean meal Walnut shell grits Abrasive media ü Blas%ng increased total tomato yield by up to 44% ü Ra%o of M:NM not influenced by blas%ng

15 Weed density 25 days aaer 1 st applica%on in pepper 4.0 Weed density (plants plot -1 ) Number of applications ü Regardless of media, blas%ng 1x reduced weed density by 55% and blas%ng 2x reduced weed density by 80%

16 End- of- season weed biomass in pepper 0.6 Weed biomass (kg plot -1 ) Weedy check Treated ü Blas%ng, regardless of media or number of blasts, reduced end of season weed biomass by 97%

17 Total pepper yield (marketable and non- marketable) 14 Total fruit yield (tons acre -1 ) Weedy check Treated Hand-weeded ü Blas%ng increased yields by 29.5% ü Ra%o of M:NM not influenced by blas%ng

18 Crop damage is a concern, but no disease or yield loss observed

19 Early weed growth stage is cri%cal for effec%ve control

20 Ongoing research Improved nozzle design Mechanized vegetable crop applicator Nitrogen mineraliza%on and uptake from organic fer%lizer grits (lab and field) On- farm trials in tomato, pepper, broccoli, and kale (with and without plas%c) Integra%ng abrasive weeding with different mulches and %llage regimes

21 Organic fer%lizers applied as abrasive grits Available NO 3 - (mg kg -1 ) No grit control Corn gluten meal Sustane Soybean meal Walnut shell grit may double Days of incubation available soil nitrogen 2-3 weeks aaer Available NH 4 + (mg kg -1 ) No grit control Corn gluten meal Sustane Soybean meal Walnut shell grit 2 applica%on Days of incubation

22 Available soil N increased by 23% when combined with (bio)plas%c mulch Net available N ( m g N/10 cm 2 ion-membrane/season) Bioplastic Polyethylene Straw mulch Mulch treatment Soybean meal Sustane Weed free (no fertilizer) Bare soil

23 Straw mulch reduced available soil N by 73%- 81% (even when combined with organic fer%lizers)

24 Abrasive weeding increased pepper yield by 20%- 30% rela%ve to weedy check in plas%culture Total pepper yield (g/plot) Bare soil Straw mulch Bioplastic Polyethylene Weedy check Weed free check Walnut shells Soybean meal Sustane Abrasive grit type

25 A new grit applicator for vegetable crops is complete

26 Poten%al uses for new applicator are being explored Bare soil systems: Broccoli and kale: hmps:// v=s1d68uje6ie Plas%culture systems: Tomato and pepper: hmps:// v=0vmgmswzvqe Plas%c film edges: hmps://

27 Ques%ons? hmp://urbanag.cropsci.illinois.edu