Lettuce irrigation with wastewater from pistachios processing Efgect on soil properties P. Kostopoulos 1 , A. Papadopoulos 1 , Y . Troyanos 1 , Ch. Kolovos 1 , S. Kosmidis 1 , M. Psychogiou 2 , M.K.Doula 1 1 Benaki Phytopathological Institute 2 Agricultural University of Athens,
Cyprus 2016, Saturday, 25 June
Dehulling pistachio waste So far little is known regarding the fate of pistachio’s waste in Greece and in other Mediterranean countries. It is known, however, that, on average , 2m 3 /h of water are required for dehulling 1tn fresh nuts , while the processing of 1tn of pistachios produces almost 2.5tn of sludge, which consists of hulls, nuts and water. Management practices: ■ Disposal in evaporation ponds ■ Disposal on soils and on water recipients
Wastewater from pistachios dehulling Parameters Value Electrical Conductivity 6,4 (6,08) (mS/cm) pH 5,22 Polyphenols, g L -1 5,5 COD g L -1 12 ΝΗ 4 + mg L -1 9,0 ΝΟ 3 - mg L -1 102 Potassium g L -1 1,0 Calcium (%) (w/v) 0,03 Magnesium (%) (w/v) 0,01 Sodium mg L -1 180 PO 4 3- mg L -1 91 Iron mg L -1 0,51 Copper mg L -1 0,13 Zinc, mg L -1 1,39 Mangannese, mg L -1 0,68 Boron, mg L -1 5,5 Chloride, mg L -1 1000 (2122)
Soil used for the experiment Parameters Value Normal values T exture Sandy Medium coarse Loam Electrical Conductivity 1250 < 2000 (μS/cm) pH 7,39 6,1-7,8 Organic Matter (%) 5,6 > 2,0 T otal Nitrogen (mg/g) 3,4 > 1,5 CaCO 3 (%) 28 0,2-5,0 Exchangeable K (cmoℓ+/kg) 0,80 0,3-1,2 Exchangeable Ca (cmoℓ+/kg) 30 Exchangeable Mg (cmoℓ+/kg) 1,8 0,4-1,5 Available P (mgP/kg) 33 5-20 Available Fe (mg/kg) 8,9 12-50 Available Cu (mg/kg) 1,3 0,9-3,0 Available Zn (mg/kg) 18 3,0-8,0 Available Mn (mg/kg) 4,4 15-50
The 10 weeks greenhouse experiment Lettuce seedings were irrigated with 5 wastewater/water ratios treatments 1:10, 1:6, 1:2, No dilution and fresh water Each treatment 5 replicates in a Latin square experimental design Plants were irrigated twice a week by adding 100ml of liquid while leachates were collected at a weekly basis. The experiment lasted 10 weeks. During the 5 th week the plants were fertilized with KNO3 (13-0-46) by adding 6,2 g per pot Leachates were further analyzed for electrical conductivity, pH, NO 3 - , Cl - , Leachates were further analyzed for electrical conductivity, pH, NO 3 - , Cl - , Na, K, polyphenols, Cu, Zn, Mn, and Fe. After experiment completion, the Na, K, polyphenols, Cu, Zn, Mn, and Fe. After experiment completion, the substrates were collected and analyzed for pH, EC, OM, polyphenols, total substrates were collected and analyzed for pH, EC, OM, polyphenols, total N, available P, exchangeable cations (K, Na, Ca, Mg), B, and available N, available P, exchangeable cations (K, Na, Ca, Mg), B, and available metals in order to assess potential impacts on soil properties after metals in order to assess potential impacts on soil properties after harvesting.
Some important fjndings Polyphenols in leachates mg/l weeks The effect of dilution was recorded in yield parameters. Chlorides in leachates Potassium in leachates mg/l mg/l weeks weeks
And more…. Leachates’ Electrical Conductivity mS/cm weeks
Soils Electrical Conductivity after the end of the experiment 9000 8000 7000 6000 5000 ) m /c 4000 S (μ 3000 C 2000 E 1000 0 Μ 1/10 1/6 1/2 F Treatments Total Nitrogen in soils after the end of the experiment 3,1 3,05 g/g) 3 2,95 otal Nitrogen (m 2,9 2,85 2,8 2,75 2,7 2,65 2,6 Μ 1/10 1/6 1/2 F T Treatments
Available Phosphorus in soils after the end of the experiment 18 16 14 12 ) 10 g k 8 / g Exchangeable Potassium in soils after the end of the experiment m 6 ( s 4 10 u r o 2 9 h p 0 8 s o Μ 1/10 1/6 1/2 F h 7 P ) g 6 v . k Treatments A l/ 5 o m 4 c ( 3 m Organic m atter (%) 2 iu s 1 s a 0 t o Μ 1/10 1/6 1/2 F P . h Treatments c x E Soil Organic Matter after the end of the experiment 7 6 5 4 3 2 1 0 Μ 1/10 1/6 1/2 F T reatments
Considering soil parameters after Exchangeable Magnesium in soils after the end of the experiment experimentation and also soil 3,5 quality thresholds (Doula et al., 3 2013), it can be proposed that 2,5 the use of pistachio wastewater for irrigation after 1:10 (and also 2 ) g k 1:6 after specifjc preconditions) l/ o 1,5 m could provide the anticipated and c ( 1 well known advantages of g M 0,5 wastewater reusing on soils, . h c x while at the same time protects 0 E Μ 1/10 1/6 1/2 F soils from overloading with salts Treatments and nutrients. Polyphenols in soils after the end of the experiment 80,00 70,00 Polyphenols (mg/kg) 60,00 50,00 BUT… 40,00 30,00 20,00 10,00 0,00 Μ 1/10 1/6 1/2 F Treatments
…the obtained yield 29 14 suggests 1:10 dilution as 53 73 % % the optimum one… % % …still we are happy… Change in fresh weight of lettuce …for 10 weeks … Fresh weight (g) 80 • We irrigated 20 times each lettuce 70 • 2lt waste/water added to 60 each lettuce 50 • 200ml waste to each lettuce 40 and 10 lt waste for 50 30 lettuces 20 …and in Greece we produce 10 almost 125.000.000 lettuces/y 0 Fresh water. 1:10. 1:6. 1:2 MΑΡΤΥΡΑΣ 1/10 1/6 1/2 ΠΥΚΝΟ Waste. T reatments
Thank you for your attention Dr. Maria K. Doula Benaki Phytopathological Institute Greece
E le c tr ic a l C o n d u c tiv ity., m 14 Under tree canopy 12 60-90cm 10 8 6 4 2 0 A B Γ E Z K N Ξ Ο Π Σ Τ Y 12 Waste on soil 10 60-90cm 8 6 4 2 0 … A E Z P Σ Y abou t soil
E le c tr ic a l C o n d u c tiv ity, m 12 Under tree canopy 30-60cm 10 8 6 4 2 0 A B Γ E Z K N Ξ Ο Π Σ Τ Y 12 Waste on soil 30-60cm 10 8 6 4 2 0 … A E Z P Σ Y abou t soil
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