Rothamsted Research where knowledge grows Rothamsted Research where knowledge grows

Why the world needs weed biologists

Jonathan Storkey (Rothamsted Research)

Rothamsted Research where knowledge grows Rothamsted Research where knowledge grows

Arable flora

Competition with the crop (weeds)

Support of Ecosystem services

Conservation value

- +

How does non-chemical control impact weeds?

Conventional farmers are being forced to use non-chemical methods (IWM)

Crop yield loss and weed seed return = “what does the label say?” vs. MANAGEMENT X WEED BIOLOGY X ENVIRONMENT

The complexity of IWM

The importance of weed biology

http://web.adas.co.uk/WeedManager/

Wild oats (A.ludoviciana)

Black-grass

“Many little hammers” – black-grass

“Many little hammers” – wild oats

Managing uncropped land in order to enhance biodiversity benefits of the arable farmed landscape.

Introduction to Farm4bio

The primary aim of the Farm4bio project was to determine whether management of un-cropped land for biodiversity

on conventional farms can achieve significant and measurable increases in biodiversity that are at least equivalent to those attained on organic farms with a primarily arable cropping

system.

Greater weed diversity on organic farms

Plant species

richness

Year (2008, 09, 10) Region (SE, SW) Organic (+/-) Project

treatments

Un-cropped

land

* (38.8, 39.2, 43.5)

*** (51.5, 29.5)

NS

NS

Cropped field

** (14.2, 16.7) *** (20.9, 10.0) ** (22.4, 14.3) NS

Greater weed diversity on organic farms

…and greater abundance of some birds

Weeds vary in their biodiversity value

Marshall EJP et al (2003) Weed Research 43:79-89

Weed species No. of insect species Importance in bird diets Wild oats 5 Black-grass 6 Cleavers 30 Charlock 37 ** Scentless mayweed 31 Chickweed 71 *** Annual meadow grass 53 ** Groundsel 46 ** Mouse-ear chickweed 22 ** Field speedwell 1 Field pansy 2 ** Fat hen 31 *** Knotgrass 61 *** Smooth sowthistle 28 * Dock 79 **

This can be captured by grouping weeds

Herbaceousarable plants

LifeformLifeform PerennialsAnnuals

Timing ofgerminationTiming of

germinationAutumn Spring

Maximumheight

Maximumheight

Abovecrop

Abovecrop

Belowcrop

Belowcrop

Floweringtime

Floweringtime

Early Late

Group 3 Group 4

SeedsizeSeedsize>=2.5 mg <2.5 mg

Group 1 Group 2 Group 5 Group 6

Maximumheight

Maximumheight

Group 7

Weeds vary in their biodiversity value

0

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Organic systems tend to select for more ‘beneficial’ weed species.

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Organic Conventional

More broad-leaf, spring and perennial weeds

Michael J. O. Pocock et al. Science 2012;335:973-977

Published by AAAS

Increased organic matter may also lead to increased weed diversity (<competition?)

0

200

400

600

800

1000

1200

1400

Farmyard manure Inorganic fertiliser

Bio

mas

s (m

-2)

Annual meadow grass

Shepherds purse

Venus' looking glass

Creeping thistle

Knotgrass

Parsley piert

Field speedwell

Dock

Vetch

Corn buttercup

Shepherd's needle

Chickweed

Mayweed

Poppy

Black-grass

Wheat