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

1. The 2nd International Conference on: Novel and Sustainable Weed Management in Arid and Semi-Arid Agro-Ecosystems Soil application of olive mill wastewater as an ecological approach for weed control in sustainable agricultural systems 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.

2. Most olive oil production is concentrated in Mediterranean countries

3. Products of the oil production process Olive oil Olive mill waste water Olive leaves Olive mill solid waste

4. Traditional olive mill: discontinuous press extraction Extracting oil from paste Crushing and malaxing Liquid extraction Storage - bottling Separation

5. 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 ofOMW – olive mill wastewater.

6. Olive mill wastewater: general characteristics Much larger than allowed in domestic sewage

7. olive mill waste as an environmental contaminant regulations: discharging directly to the sewage system or to the environment is not allowed (COD>>>2,000 mg/L). However, from lack of cost-effective alternatives un-controlled release into the environment and contamination of rivers and water resources are common

8. Controlled land spreading of OMW Pro • exploited as organic fertilizer • increase soil organic matter • promote microorganism activity • Improve soil structure Con • phytotoxicity and biotoxicity • increased salinity • ground water contamination

9. At present: OMW = Environmental problem Solutions natural alternative to synthetic herbicides Engineered systems OMW=Unwanted waste Agricultural reuse OMW=Resource

10. Weeds in olive orchards The growing trend of consumers worldwide is to reduce chemical herbicide application Apart from potassium soup (soft soup) and acetic acid (vinegar) – which are expensive and not very efficient, there are no organically acceptable herbicides Reduction in olive yield Reduction of plant vigor Increased risk of disease

11. The oldest evidence of the herbicidal nature of olive mill waste Roman Agricultural Writer 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 andweeds will not grow On agriculture - Cato Marcus Porcius Cato (234-148 BCE)

12. 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.

13. Experimental design

14. Application modes: POST PRE PPI

15. Data collection: Seedling, emergence and height were monitored periodically Final biomass

16. 0 m3/ha-1 20 m3/ha-1 80 m3/ha-1 160 m3/ha-1 PRE – seedling emergence

18. Emergence time course of Sylibummarinatum – PRE and PPI PRE PPI Cumulative emergence (% of Emax) Time from sowing (days) ───── 0 m3/ha ───── 20 ───── 80 ───── 160

19. The influence of PPI OMW application on Phalaris biomass control PPI

20. The effect of different levels of OMW application on phalaris DW Dry weight per pot (g) OMW dose m3/ha

21. The effect of omw on phalarisbrachystachysdevelopement PRE PPI Height (cm) Time (days)

22. 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.

23. 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. .

26. CONTROL PRE

27. Effect of OMW application on Phalaris DW under field conditions a a a a b b

28. Enrichment of the top soil layer with DOC and TP as affected by OMW application PRE PPI

29. 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.

30. CONTROL PRE THANKS • EWRS for the scholarship • NeweYa’ar, the department of Weed Research: • Dr. Joseph Hershenhorn, Dr. Radi Ali, Dr. Daniel Joel, • Evgeny Smirnov, Tal Lande, Guy Achdari, • Dr. EvgenyaDor, Dr. Dina Plakhin • The faculty of agriculture, • Weed lab • My fellow students