3.2. Crop performance indicators
Statistical analysis showed that cucumber plant height of treatment 4 increased significantly as compared with other treatments
except for treatments 2 and 3 (Table 5), However, leaf area were not
significantly affected by the RWW treatments. Tomato plant height
was not affected by treatments, while plant leaf area improved
significantly by treatment 3 followed by treatments 2 and 4.
Cucumber stem and root dry weights were not significantly different with the RWW treatments but significant increase in leaf dry
weight was observed with the application of chemical-fertilizers
treatments as shown in Table 5. Tomato stem and leaf dry weights
were not significantly affected by the RWW application. The lowest
root dry weight was observed in treatment 1. Organic carbon might
have had indirect effect on plant growth. For example, Thurman
(1985) showed that dissolved organic carbon was an important factor in soil ecosystem as it was capable of adjusting soil pH, microbial
activity, and nutrient bioavailability and mobility.
Table 5 showed that cucumber plant vegetative growth was significantly affected by the treatments; these Tables also indicate
that the application of RWW was sufficient to produce vegetative growth parameters matching those produced when complete
chemical fertilizers were applied. However, treatments 2–4, in case
of tomato, resulted in increase in tomato vegetative growth as
evidenced by leaf area. This could be attributed to the relatively
higher salt tolerance of tomato as compared to cucumber. Cucumber plants is considered salt-sensitive crop (Jones et al., 1989;
Chartzoulakis, 1994). To the contrary, Maas and Hoffman (1977)
classified both crops as moderately sensitive to salt stress but the
percent reduction per unit increase in salinity beyond the threshold value of 2.5 dSm
−1
was 13% for cucumber as compared to 9.9%
for tomato. The results of Table 8 show relatively high soil salinity
at the beginning and end of the experiment. The highest cucumber
fruit yield and average fruit weight were observed from treatment
3 as contrasted by the lowest yield and fruit weight of treatment
5 (Table 6). Tomato fruit yield and average fruit weight was not
significantly affected by RWW treatments (Table 6). However, the
highest tomato yield was that of treatment 4. In this regard, AlLahham et al. (2003) reported an increase in tomato fruit size and
weight when irrigated with reclaimed domestic wastewater. Subsequently, these authors suggested that the reclaimed wastewater
can replace fresh water in irrigation of tomatoes eaten after cooking provided that the effluent quality is continuously monitored
to avoid microbial contamination. In general, our results indicated
that using RWW had the capacity to produce cucumber and tomato
fruit yield not significantly different from these produced when
the crops were provided by their K-nutritional requirement in the
form of chemical fertilizers. Additional improvements in soil physical and biochemical edaphic properties were reported. This can be
attributed to the extra application of RWW-micronutrients and to
the ameliorative effect of that organic solutes-rich water