Monitoring report on nursery horticultural production

The results clearly showed that in pomegranate cutting, the plant variety influenced the chemico-physical transformation of the substrates, since in presence of Purple Queen cultivar, a greater increase in nutrients and micro and macro elements was generally observed in both sites (mainly in Florence), indicating a higher release from substrates or a lower plant absorption. In all the substrates, a low organic matter mineralization, due to the probable stability of the substrate and a reduction in heavy metals (absorbed by plants), in particular in sediment substrates (TS50-TS100), was found. Also an increase over the time of N-NO3 was generally detected, indicating an improvement of physical characteristics and a better oxygenation of these substrates. On the other hand, the enzyme activities, for their higher environmental sensitivity, showed a similar trend between the pomegranate cutting cultivars, but different in the two sites. In Caliplant trials, all the enzyme activities greatly increased over the time in all the substrates, suggesting an activation of microbial population that could be due to a development of roots. Differently, at -glucosidase and phosphatase, generally remained constant or decrease in T0, probably due to the already availability of nutrients, while remain constant or increased in TS50 and TS100. On the contrary, arylsuphatase increased at the end of the cycle in TS0 and TS50. Regarding the substrates for lettuce seedling, the results clearly showed a higher content in organic substance in the peat used in May, as confirmed by the higher content in organic matter and nutrients both in the total (TN) and soluble (N-NH3, N-NO3 and PO4) forms, and micro and macro elements. However, all the substrates in both experimentations (May and September) showed an appreciable nutrient content and biochemical activities. In conclusion, also for these trials on pomegranate cutting and lettuce seedling, it can be affirmed that the agronomic and functional properties of all the substrates were probably acceptable for plant growth and development also in the substrate prepared just with sediments. Of course, the chemical and biochemical results of the agronomic substrates should be compared and discussed with the results of plant growth and physiology. The possibility to apply treated sediments to the common substrates for lettuce and pomegranate propagation was assessed. Root system of pomegranate cuttings developed well in all sediment based substrates but it showed a different pattern of development, with secondary roots occupying the whole pot volume in coconut fiber commercial substrate, expanding on the wall sides of the pots and developing downwards (sometimes coming out throughout the hole of the pot base) in TS100. Some problems were faced with dredging at the beginning of the trials, but they were solved adjusting the amount of water for irrigation; the use of sediment based substrates also allowed water saving. In general pomegranate saplings cultivation grew according to common quality standards in the substrate containing at least 25-30% of coconut fiber (i.e. in the substrates TS70 - TS75), even if they grew also in TS100. Lettuce saplings are commonly obtained through propagation by seed and this practice requires the use of substrate with a very fine structure; for this reason when the first demonstration was set remediated sediment was used at a lower concentration (TS25 and TS50) and in the second it was sieved to 5 mm to reduce the aggregates in the sediment. So a sediment based substrate for sowing need to be treated differently than for other propagation techniques: first a reduction of the aggregates in the sediment is needed and the use of substrates with no more than 50% of sediment is recommended.