1. Dalia Erez-Reifen. 1,2, Laor Y. 1, Raviv M. 1, Rubin B. 2 and Eizenberg H. 1 1 Agricultural Research Organization, Newe Ya'ar Research Center, Ramat-Yishay, Israel. 2 Robert 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 2 nd International Conference on: Novel and Sustainable Weed Management in Arid and Semi-Arid Agro-Ecosystems

2. Most olive oil production is concentrated in Mediterranean countries

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

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

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 of OMW – olive mill wastewater.

6. 3.0-5.9pH 40,000-220,000COD (mg/L) 23,000-100,000BOD (mg/L) 1-103Total solids (g/L) 1-23Fats (g/L) 0.002-80Polyphenols (g/L) 0.78-10Volatile organic acids (g/L) 0.3-1.2Total nitrogen (g/L) Olive mill wastewater: general characteristics Much larger than allowed in domestic sewage

7. 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 sewage system or to the environment is not allowed (COD>>>2,000 mg/L).

8. 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

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

10. 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 vigor Increased risk of disease Weeds in olive orchards

11. 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

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 LevelsTreatmentsFactor 3PPI, PRE, POST Application modes 40, 20, 80, 160 (m 3 /ha) Application levels 3 Daucus carota, Silybum marianum, Phalaris brachystachys Weed species 5 Replications

14. Application modes: POST PRE PPI

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

16. PRE – seedling emergence 0 m 3 /ha -1 20 m 3 /ha -1 80 m 3 /ha-1160 m 3 /ha -1

18. Emergence time course of Sylibum marinatum – PRE and PPI PRE Cumulative emergence (% of E max ) Time from sowing (days) ───── 0 m 3 /ha ───── 20 ───── 80 ───── 160 PPI

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

20. The effect of different levels of OMW application on phalaris DW OMW dose m 3 /ha Dry weight per pot (g)

21. Height (cm) Time (days) PREPPI The effect of omw on phalaris brachystachys developement

22. In conclusion Omw application at and above 80 m 3 /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. PRECONTROL

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

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 m 3 /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. 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