• Energy Research

Research on the application of innovative biodegradable materials for substrate mulching in greenhouse floricultural cultivation was carried out in Southern Italy. A transparent biodegradable film and a transparent biodegradable spray coating were compared with a commercial transparent low density polyethylene film. The biodegradable film was a starch based extruded material, the sprayed coating was created from a polysaccharide solution. The materials were used to mulch the peat and perlite growing media contained in trays during snapdragon cultivation in order to increase the substrate temperature and hasten early growth. The climate variables inside and outside the greenhouse and the growing medium temperature under the mulching materials were recorded. Biometrical data, such as mean blooming time, plant height and spike length, were collected. The laboratory radiometric tests showed that the biodegradable mulching materials had a lower solar transmissivity in comparison to the low density polyethylene film. The capacity to reduce the long wave infrared thermal losses was higher for the biodegradable mulches: the long wave infrared transmissivity coefficient was 53.9% for the low density polyethylene film, 12.1% for the biodegradable film and 8.2% for the spray coating. The increase of the growing medium temperature allowed the harvest of the snapdragon grown in the mulched trays 7 days before that of the flowers grown in the un-mulched trays. At the end of the crop cycle the disposal of the biodegradable mulching materials was carried out fragmenting and mixing them with plant residue and the growing medium. The residue biodegraded in almost 1 month for the spray coating and in about 12 months for the biodegradable film.

To assess the effect a new animal-derived biostimulant on the growth, root morphology, nitrogen content, leaf gas exchange of greenhouse potted snapdragon, three treatments were compared: (a) three doses of biostimulant (D): 0 (D0 or control), 0.1 (D0.1), and 0.2 g L-1 (D0.2); (b) two biostimulant application methods (M): foliar spray and root drenching; (c) two F1Antirrhinum majus L. hybrids (CV): "Yellow floral showers" and "Red sonnet." The treatments were arranged in a randomized complete-block design with four replicates, with a total of 48 experimental units. Plant height (+11%), number of shoots (+20%), total shoot length (+10%), number of leaves (+33%), total leaf area (+29%), and number of flowers (+59%) and total aboveground dry weight (+13%) were significantly increased by the biostimulant application compared to the control, regardless of the dose. The lowest dose resulted in the best effect on the ground plant dry weight (+38%) and, in order to the root system, on total length (+55%), average diameter (+36%), volume (+66%), tips (+49%), crossings (+88%), forks (+68%), projected (+62%), and total surface area (+28%). Compared to the control, plants treated with the biostimulant significantly enhanced leaf (+16%) and root (+8%) nitrogen content, photosynthetic rate (+52%), transpiration rate (+55%), and stomatal conductance (+81%), although there were no changes in dark-adapted chlorophyll fluorescence. Differences in the application method were not evident in the aboveground morphological traits, except in the plant shoot number (root drenching: +10%). The foliar spray compared to root drenching had a significant effect only on flower dry weight (3.8 vs. 3.0 g plant-1). On the other hand, root drenching had a positive effect on ground dry weight (2.7 vs. 2.3 g plant-1), root morphology, leaf-N and root-N content (+3%), transpiration rate (+21%), stomatal conductance (+40%), concentration of CO2 in intracellular spaces (+11%), as well as on the efficiency of Photosystem II (+11%). A higher pot quality was obtained in "Red sonnet" compared to "Yellow floral shower." Based on our findings, applying the biostimulant to potted snapdragon at the lowest dose, as part of a fertilizing regime, improves the crop quality in an agro-environmental sustainable way.

The problems associated with the salinization of soils and water bodies and the increasing competition for scarce freshwater resources are increasing. Current attempts to adapt to these conditions through sustainable agriculture involves searching for new highly salt-tolerant crops, and wild species that have potential as saline crops are particularly suitable. The common ice plant (Mesembryanthemum crystallinum L.) is an edible halophyte member of the Aizoaceae family, which switches from C3 photosynthesis to crassulacean acid metabolism (CAM) when exposed to salinity or water stress. The aim of this review was to examine the potential of using the ice plant in both the wild and as a crop, and to describe its ecology and morphology, environmental and agronomic requirements, and physiology. The antioxidant properties and mineral composition of the ice plant are also beneficial to human health and have been extensively examined.