The article presents the results of research consisting of the application of deficit irrigation (DI) criteria, combined with the adoption of micro-irrigation methods, on orange orchards (Citrus sinensis (L.) Osbeck) in Sicily (Italy) during the irrigation season of 2015. Regulated deficit irrigation (RDI, T3) and partial root-zone drying (PRD, T4) strategies were compared with full irrigation (T1) and sustained deficit irrigation (SDI, T2) treatments in terms of physiological, biochemical, and productive crop response. A geophysical survey (electrical resistivity tomography, ERT) was carried out to identify a link between the percentages of drying soil volume in T4 with leaves abscisic acid (ABA) signal. Results highlight that the orange trees physiological response to water stress conditions did not show particular differences among the different irrigation treatments, not inducing detrimental effects on crop production features. ABA levels in leaves were rather constant in all the treatments, except in T4 during late irrigation season. ERT technique identified that prolonged drying cycles during alternate PRD exposed more roots to severe soil drying, thus increasing leaf ABA accumulation.

(1) Background: The commercial sustainability of the citrus nursery industry involves cutting costs by using alternative planting substrates to replace (or partially replace) the conventional black peat. Conifer wood biochar was evaluated as a component of the growth medium in a commercial citrus nursery for Carrizo citrange seedlings. (2) Methods: Seven growth media mixtures (A–G) were tested. Each mixture consisted of 50% sandy volcanic soil with the remaining 50% made up as follows: A = black peat and perlite 1:1; B = biochar 1; C = black peat, perlite, and biochar 0.5:1:0.5; D = black peat and biochar 1:1; E = black peat, compost, and biochar 0.5:0.5:1; F = black peat, perlite, compost, and biochar 0.5:0.5:0.5:0.5; G = black peat and lapillus 1:1, this substrate, previously adopted by the hosting nursery, was the control. (3) Results: The best media for the rootstock studied here were those containing 25% biochar (mixtures D and E). In the deeper layers the substrate was more compact, and the roots were limited to the shallow layers of the pot. (4) Conclusions: Conifer wood biochar can be partly added in place of peat in growth media mixtures, thus reducing costs and ameliorating sustainability.

Citrus is a subtropical fruit tree with high water requirements. This study aimed to determine the effects of water deficit on an orange orchard subjected to different water-saving strategies. The study was realised in an orange orchard in a semiarid area by adopting four different water management techniques: 100% crop evapotranspiration (control); SSDI—subsurface sustained deficit irrigation; RDI—regulated deficit irrigation; PRD—partial rootzone drying treatment during five growing seasons. The experimental design foresaw a randomised block design with six replicates per treatment (24 index plants). The results of the study showed that the water-saving strategies reduced irrigation water consumption by 25% (SSDI), 33% (RDI), and 49% (PRD) compared to the fully irrigated treatment without yield reduction, thus increasing water use efficiency. Mineral nutrition of the trees was slightly affected by irrigation treatments; element concentration in leaves was generally in the optimal range; only potassium showed values below the recommended leaf concentrations. Regarding fruit quality parameters, the vitamin C concentration in RDI showed significant differences with a value of 62.7 mg 100 mL⁻¹ compared to 58.5 mg 100 mL⁻¹ in the control. Plants subjected to SSDI and PRD strategies showed increased levels of pulp colour index with significant values of 10 and 9.90, respectively, compared to the control (8.44). By implementing targeted water management, citrus growers could save water and increase the ascorbic acid and sugar concentration in the fruits; anthocyanins also increased but not significantly. These findings open new market opportunities for citrus growers in marginal areas, where they cannot rely solely on producing citrus fruits to remain competitive.

The effect of basal zone defoliation on vines influences yield and ripening depending on the phenological stage and its intensity. Early basal defoliation (EBD) was carried out at flowering on the autochthonous Vitis vinifera (L.) cultivar ‘Nerello mascalese’ grown on the eastern slopes of Mount Etna, Sicily. The effects were evaluated over a two-year period. In the first year, the canopy retained 67 % of its original leaf area after EBD and in the second year, 58 %. Compared with control vines, mid-day leaf water potentials in the EBD vines enjoyed higher water status throughout the growing seasons in both years. EBD had no significant negative effects on yield but did have significant positive effects on the levels of total polyphenols, total flavonols and total anthocyanins. Yield and its components are conditioned by a number of factors mainly linked to climate and to the vines’ general condition during berry growth and ripening. Even after two consecutive years of treatment, EBD does not have any negative effects on yield. However, EBD does have strong positive effects on berry quality attributes as a consequence of the following: greater exposure of the cluster to sunlight, higher vine water status and avoidance of high temperature stresses in the last phase of ripening during the analysis of anthocyanin.

Bottlenecks occur as the cultivated area increases and the inappropriate mechanization methods hinder the stable supply of seeds for hemp multiplication. Moreover, the seeds ripen scalarly, and a timely stabilization is required to impede a germinability reduction. The study coupled the delayed sowing of a non-specific hemp variety to a harvesting system allowing for the collection of seeds with other threshing fractions. The final goal was the identification of an innovative route integrating agronomic and mechanical aspects for the improvement of the supply chain of seed production. To this aim, harvesting trials were carried out on the variety Futura sowed at the end of June in North Italy and were collected with a combine equipped with a separator developed for the recovery of threshing residues. The shortening of the growth cycle did not affect the plant height (173 cm on average). The effective working time of the combine was 57% of the total working time and the field efficiency was 1.14 ha h⁻¹, a good performance considering that in our work the seeds was threshed simultaneously to the harvest operation. Seed losses were found to be mostly at the expense of the mowing and threshing system (sector B) but remained below 5%. The separation system allowed for the rescue of 492.20 kg ha⁻¹ (DW basis) of high-value threshing residues.

In intensive strawberry production, monoculture is a common practice worldwide; however, prolonged replanting can cause plant disorders and jeopardize profitable cultivation of this highly valuable crop. To mitigate replanting problems, the strawberry industry is still highly dependent on chemical fumigation. Given the increasing regulatory restrictions and concerns about human and environmental risks from fumigants use, there is a growing interest in the adoption of effective, non-chemical alternatives. Two non-chemical soil fumigation practices, i.e., anaerobic soil disinfestation (ASD) and bio-fumigation with biocide plants (BIOFUM), were tested against chemical fumigation by chloropicrin + 1,3-dichloropropene mixture (STANDARD) and untreated (UNTREAT) control in a 2-year trial established in a commercial strawberry farm in Southern Italy (40°25′ N, 16°42′ E). Overall, the alternative practices provided consistently better results than UNTREAT; whereas, compared to STANDARD, their performance was significantly different in the two years: in 2018/19 season the alternative practices registered a 20% (ASD) and 39% (BIOFUM) marketable yield loss compared to STANDARD, while in the 2019/20 season yield differences were not significant. Although both practices appear promising as eco-friendly alternatives to chemical fumigation, in this short-term trial ASD performed better than BIOFUM both in terms of yield and fruit size, resulting in a more advanced stage for practical adoption.