Dalia Erez-Reifen.1,2, Laor Y.1, Raviv M.1, Rubin B.2 and Eizenberg H.1

1Agricultural Research Organization, Newe Ya'ar Research Center, Ramat-Yishay, Israel. 2Robert H. Smith Faculty of Agriculture, Food and Environment The Hebrew University of Jerusalem, Israel.

Soil application of olive mill wastewater as an ecological approach for weed control in

sustainable agricultural systems

The 2nd International Conference on: Novel and Sustainable Weed Management in Arid and Semi-Arid Agro-Ecosystems

Most olive oil production is concentrated in Mediterranean countries

Products of the oil production process

Olive mill solid waste Olive leaves

Olive mill waste water

Olive oil

Traditional olive mill: discontinuous press extraction

Crushing and malaxing

Extracting oil from paste

Separation

Storage - bottling

Liquid extraction

Transition from traditional to modern extraction techniques

Around the 80’s, most of the small traditional olive mills were replaced by large ones with high capacity of daily

processing .

Continuous plants need higher amount of process water and give rise to the production of huge amounts of OMW – olive mill wastewater.

3.0-5.9 pH

40,000-220,000 COD (mg/L)23,000-100,000 BOD (mg/L)

1-103 Total solids (g/L)1-23 Fats (g/L)

0.002-80 Polyphenols (g/L)0.78-10 Volatile organic acids (g/L)0.3-1.2 Total nitrogen (g/L)

Olive mill wastewater:general characteristics

Much larger than allowed in domestic

sewage

olive mill waste as an environmental contaminant

However, from lack of cost-effective

alternatives un-controlled release into the

environment and contamination of rivers

and water resources are common

regulations: discharging directly to the sewagesystem or to the environment is not allowed

(COD>>>2,000 mg/L).

Controlled land spreading of OMW

exploited as organic fertilizer increase soil organic matter promote microorganism activity Improve soil structure

phytotoxicity and biotoxicity increased salinity ground water contamination

Con

Pro

Solutions

At present:OMW = Environmental problem

Engineered systemsOMW=Unwanted waste

Agricultural reuseOMW=Resource

natural alternative to

synthetic herbicides

Apart from potassium soup (soft soup) and acetic acid (vinegar) – which are expensive

and not very efficient, there are no organically acceptable herbicides

The growing trend of consumers worldwide is to reduce chemical

herbicide application

Reduction in olive yield Reduction of plant vigorIncreased risk of disease

Weeds in olive orchards

Roman Agricultural Writer

Marcus Porcius Cato (234-148 BCE)

Uses for Amurca (omw)Make a threshing floor as

follows: Dig over the site, then drench with

amurca and allow to soak in, then break up the

ground thoroughly. Then level, and pound with a rammer. Finally drench again with amurca and

allow to dry. If you make it in this way, ants will not damage it and weeds

will not grow

The oldest evidence of the herbicidal nature

of olive mill waste

On agriculture - Cato

Research Objectives• Evaluate the efficacy of OMW as a bio-herbicide.

• Optimize modes of application and rates of OMW.

• Evaluate the response of various weed species to OMW applications.

Experimental design

Levels Treatments Factor

3 PPI, PRE, POST Application modes

4 0, 20, 80, 160 (m3/ha) Application levels

3Daucus carota ,Silybum marianum, Phalaris brachystachys

Weed species

5 Replications

Application modes :

POST

PRE

PPI

Data collection:

Seedling, emergence and height were monitored periodically

Final biomass

PRE – seedling emergence

0 m3/ha-1 20 m3/ha-1 80 m3/ha-1 160 m3/ha-1

Emergence time course of Sylibum marinatum – PRE and PPI

PRE

Cum

ulat

ive

emer

genc

e (%

of E

max

)

Time from sowing (days)───── 0 m3/ha───── 20───── 80───── 160

PPI

0 5 10 15 20 25 300

20

40

60

80

100

120

0 5 10 15 200

20

40

60

80

100

120

The influence of PPI OMW application on Phalaris biomass

PPI control

0 2 8 160

4

8

12

16 a

bb

c

a

b

c c

pre ppi

The effect of different levels of OMW application on phalaris DW

OMW dose m3/ha

Dry

wei

ght p

er p

ot (g

)

Heig

ht (c

m)

Time (days)

0 20 40 60 80 1000

10

20

30

40

500 2

8 16

PRE PPI

0 20 40 60 80 1000

10

20

30

40

500 2

8 16

The effect of omw on phalaris brachystachys developement

In conclusion• Omw application at and above 80 m3/ha effectively

inhibits both weed emergence and development.

• POST treatments did not significantly injure weeds.

• PRE treatments severely reduced seedling emergence of dicot species, less reduction was observed in P. brachystachys emergence

• PPI treatments moderately affected weeds emergence, yet they significantly affected weed development and final biomass.

OMW effect under field conditions.

• Three beds were constructed between the rows of olive trees.• 14 "min plots“ 2x4 m randomly divided to:Control -no OMW,

PRE -surface spreading of 80 m3/ha, PPI- surface spreading of 80 m3/ha, incorporated to 10 cm depth, using a rotary tiller. A row of Phalaris seeds were sown in each plot and plant biomass was monitored.

• The upper soil layer was sampled using an auger at three intervals: 0-10, 20-20 and 20-30 cm depth.

• PH, EC, dissolved organic carbon (DOC) and total phenols were analyzed in saturated paste extracts.

.

PRECONTROL

Effect of OMW application on Phalaris DW under field conditions

ba

a

0

0.2

0.4

0.6

0.8

C PPI PRE

b

a

a

Enrichment of the top soil layer with DOC and TP as affected by OMW application

PRE

PPI

In conclusion• Omw application at 80 m3/ha reduced weed

biomass under field conditions but only pre treatment’s effect was statistically significant.

• Both application modes caused a significant increase of Ec, DOC and total phenols as compared with control. This impact was reduced gradually with depth and time.

• Tillage seemed to immobilize OMW constituents within the top soil layer.

EWRS for the scholarship

Newe Ya’ar, the department of Weed Research:Dr. Joseph Hershenhorn, Dr. Radi Ali, Dr. Daniel Joel,

Evgeny Smirnov, Tal Lande, Guy Achdari,

Dr. Evgenya Dor, Dr. Dina Plakhin

The faculty of agriculture,Weed lab

My fellow students

PRECONTROL