Effect of using raw waste water from food industry on soil fertility, cucumber and tomato growth, yield and fruit quality

Abstract Raw waste water (RWW) from food industry is rich of organic matter and mineral nutrients, particularly, K and to lesser extents N then P. Such richness is attributed to the nature of some substrates involved in the food processing e.g. molace of sugar beet or sugar cane. These two crops are known to require high amount of K and, thus, to further enrichment of their derivatives with that nutrient. As cost of K fertilizers is relatively high, this experiment was conducted to study the effect of applying RWW on soil fertility, yield quantity and quality of greenhouse cucumber and tomato. Uniform 30-day old cucumber seedlings and 45-day old tomato seedlings were transplanted to two multi-span greenhouses (1000 m 2 ) on December 12, 2012, at Dair Alla Research Station in Central Jordan Valley (JV). The transplanted seedlings were subjected to 5 RWW treatments of 75% of the traditional amount of K fertilizer farmers of the JV apply during the growing season, 100% of K of the traditional amount of K-fertilizer of which 25% were applied before transplanting and 75% were applied during the growing season, 125% of the traditional amount of K-fertilizer where 25% were added to the soil before transplanting and 100% were added during the growing season, traditional amounts of N, P and K chemical fertilizers, and traditional amounts of N and P chemical fertilizers only. The results showed that RWW can effectively substitute K-chemical fertilizer and can also improve some soil fertility parameters by the end of the growing season. For example, increases in available K and organic matter in the RWW treated cucumber beds were 25–71% and 2–11%, respectively. Similar increases were reported in the case of tomato beds (7–62% and 7–17%). Such increases corresponded to increases in K uptake by cucumber and tomato plants (30 and 37%, respectively). Calcium uptake was also increased to levels as high as 40 and 34% in both crop cases. Results of this study indicated that the application of Raw Waste Water from Food Industry improve cucumber and tomato performance and soil fertility.