EFFECTS OF ORGANIC AND CONVENTIONAL N-FERTILIZATION ON QUALITY TRAITS IN CORIANDER (CORIANDRUM SATIVUM L.)

In organic cropping management of Medicinal and Aromatic Plants, the best quality expression is crucial to gain satisfactory incomes. Coriander (Coriandrum sativum L.) is an annual herbaceous plant with a commercial value due to the typical scent of its fruits (commonly termed “seeds”), rich in a pale yellow oil (1-2% in small-sized types, 0.2-0.5% in large-sized ones). Several studies have been done for determining the composition of volatile fraction of Coriander, which was found to vary also as a consequence of cropping techniques, including nitrogen fertilization. In order to gain useful information about the effects, if present at all, of organic N fertilization on Coriander quality in terms of volatiles composition pattern, a three-year trial (2004-2006) was carried out using different types and rates of organic and conventional N fertilizers. Volatile composition of fruits was obtained by means of GC-MS and data were evaluated by multivariate statistical analysis. The most representative compound are linalool, followed by camphor, geranyl acetate and geraniol. The group partition was mainly due to different quantitative ratio of compounds; the differences in volatile composition, however, followed a scheme more resembling the cropping year than the fertilization management

N USE AND PARTITIONING IN CORIANDER (CORIANDRUM SATIVUM L.) AFTER ORGANIC AND CONVENTIONAL N FERTILIZATION

In coriander, a well known spice herb, many studies concerning the effect of N fertilization have been conducted in special areas where the cultivation of such plant has a major importance, such as India. Limited information is available as concerns the response of coriander to N fertilization under Mediterranean climatic conditions, above all when organic N fertilizers (mandatory when organic cropping management is chosen) are used. This work refers about some observations realised from 2004 to 2006 by an experiment on organic and mineral N fertilization techniques in coriander, carried on in the experimental farm “Sparacia” (Cammarata, AG, Sicily). Similarly to what suggested for other species, each year at harvest time, for each fertilizer treatment, seeds yield and plant biomass were weighed and the respective N content was determined in order to compare N plant uptake with total and mineral N measured in the soil before and after cropping cycle. From such data a few indices were calculated in order to get information about the efficiency of use by plants of the tested N forms. Some differences in N partitioning and use efficiency according to treatment were noticed, suggesting an overall higher efficiency of N chemical fertilizers

LA VALORIZZAZIONE DELLA FLORA SPONTANEA ATTRAVERSO LO STUDIO DI NUOVI BIOPESTICIDI: ARTEMISIA ARBORESCENS L.

Il termine “biopesticidi” identifica un vasto insieme di molecole, sintetizzate naturalmente da piante od altri organismi vegetali, in grado di manifestare un’attività biologica nei confronti di agenti fitopatogeni di diversa origine, quali virus, batteri, funghi, artropodi ed altri. Tale attività può spaziare dalla semplice repressione di un particolare stadio di sviluppo del patogeno (sporulazione, crescita vegetativa, riproduzione) fino alla induzione di reazioni e processi metabolici che ne determinano la morte. Negli ultimi anni sono stati proposti molti nuovi formulati con queste caratteristiche, la cui diffusione, pur se ancora contenuta, si presenta in continua espansione. Verso questi nuovi prodotti si orientano infatti i settori emergenti dell’agricoltura biologica e, più in generale, tutte le tecniche di produzione a basso impatto ambientale. Lo studio di nuovi formulati di derivazione vegetale segue prevalentemente due vie: la prima procede per semplice analogia, esaminando la composizione chimica di estratti ottenuti da specie botanicamente affini ad altre di cui l’azione biocida è già nota; il secondo approccio, più lungo e costoso, procede tramite l’esecuzione su ogni estratto vegetale di screening piuttosto ampi tendenti all’identificazione di eventuali azioni biocide. In questo secondo caso, le specie vegetali da esaminare vengono in genere selezionate nell’ambito della flora spontanea. La biodiversità naturale costituisce quindi un considerevole bacino a cui attingere per l’identificazione di nuove molecole attive. Un esempio abbastanza noto è costituito dal Piretro (Chrisantemum cinerariaefolium L.), studiato come pianta biocida fin dagli inizi del XX secolo ed oggi divenuto uno degli insetticidi commerciali più noti in agricoltura biologica; numerosi studi hanno tuttavia dimostrato l’esistenza di rilevanti attività biocide anche in numerose altre specie. Tra queste, Artemisia arborescens L., un’altra Asteracea spontanea e largamente diffusa nelle aree semiaride mediterranee, la cui attività biocida è stata accertata nei confronti di funghi, batteri e insetti, oltre che verso la capacità germinativa dei semi di alcune specie infestanti. A. arborescens è un arbusto alto fino a 1-2,5 metri, con rami eretti, legnosi e biancastri e foglie bipennate, aromatiche, di colore bianco-argenteo. L’olio essenziale estratto dalle foglie e dai fiori possiede diverse azioni farmacologiche e, grazie al suo alto contenuto di camazulene (11.32%), manifesta anche una spiccata e ben nota attività antinfiammatoria. Esso è risultato poco efficace contro Thrips tabaci, manifestando invece una buona efficacia nei confronti di Aphis gossipy, adulti e neanidi di Bemisia tabaci, adulti di Lymantria dispar e forme giovanili di Aonidiella aurantii. Gli screening svolti sulla specie hanno riguardato anche batteri e funghi, e A. arborescens ha mostrato in numerosi casi un soddisfacente livello di attività, che ne permette l’inserimento a pieno titolo tra le risorse naturali maggiormente meritevoli di approfonditi studi futuri

Nonchemical weeding of medicinal and aromatic plants

Medicinal and aromatic plants are major crops of domestic and industrial interest. Medicinal and aromatic plants are increasingly organically grown to enhance profitability. However, the presence of weeds may lead to a decrease in both yield and quality. Therefore, nonchemical methods of weed control are needed. In this study, mechanical weeding, flaming, stale seedbed, and biodegradable mulch were tested from 2003/2004 to 2006/2007 on coriander, fennel, and psyllium. Biomass and seed yield were measured. The biomass of weeds remaining at harvest was also measured. Results show a high sensitivity of coriander, fennel, and psyllium crops to the presence of weeds. Stale seedbed excessively delayed sowing time, thus inducing negative effects on crop seed yields. As a consequence, seed yield was 40–90 % lower than in the untreated plots. On the other hand, mechanical weeding, flaming, and biodegradable mulch reduced weeds by 50–95 %

Cropping System Stability Drives SOC Sequestration and Increases Saturation Deficit in Hot Arid Durum Wheat Cropping Systems

Stability analysis has been extensively employed in evaluating the genotype x environment interaction, but it can also be conveniently applied to cropping systems. This study applied stability analysis to a long-term experiment (1998–2016) conducted in an experimental farm in southern Italy. The experiment involved two standard semi-arid cropping systems (WW—durum wheat monocropping and WP—durum wheat–field pea rotation), with two nitrogen fertilization levels (60 kg ha−1—N60 and 120 kg ha−1—N120), along with an unfertilized control (N0). Soil organic carbon (SOC) was estimated in all treatments at the end of the experiment to investigate the potential for SOC sequestration and soil C saturation by analyzing the stability of all investigated cropping conditions in relation to SOC sequestration. The study also investigated the relationship between C input and SOC sequestration. SOC sequestration per year was higher in WW than in WP, confirming that including legumes in the rotation did not enhance the SOC content. Similarly, the positive impact of nitrogen application on biomass yield did not affect SOC accumulation. The stability analysis revealed that over the long term, WW exhibited greater stability than WP, suggesting that, in semi-arid environments, a more stable cropping system can enhance soil carbon sequestration, with nitrogen fertilization exerting a scarce influence. Segmented regression analysis identified two distinct patterns of SOC accumulation based on C input, separated by a definite threshold of C input (breakpoint) quantified at 14.7 Mg ha−1. It was found that the steady-state C level, achieved after the accumulation of this C input, was reached much faster in WW than in WP, in which it could only be inferred at 23 years. In conclusion, this study underscores the role of cropping system stability in driving SOC sequestration. Furthermore, it emphasizes the potential of stability analysis in assisting stakeholders in refining their strategies for different cropping conditions in dry and rainy environments

Arbuscular mycorrhizal fungi altered the hypericin, pseudohypericin, and hyperforin content in flowers of Hypericum perforatum grown under contrasting P availability in a highly organic substrate

St. John’s Wort (Hypericum perforatum) is a perennial herb able to produce water-soluble active ingredients (a.i.), mostly in flowers, with a wide range of medicinal and biotechnological uses. However, information about the ability of arbuscular mycorrhizal fungi (AMF) to affect its biomass accumulation, flower production, and concentration of a.i. under contrasting nutrient availability is still scarce. In the present experiment, we evaluated the role of AMF on growth, flower production, and concentration of bioactive secondary metabolites (hypericin, pseudohypericin, and hyperforin) of H. perforatum under contrasting P availability. AMF stimulated the production of aboveground biomass under low P conditions and increased the production of root biomass. AMF almost halved the number of flowers per plant by means of a reduction of the number of flower-bearing stems per plant under high P availability and through a lower number of flowers per stem in the low-P treatment. Flower hyperforin concentration was 17.5% lower in mycorrhizal than in non-mycorrhizal plants. On the contrary, pseudohypericin and hypericin concentrations increased by 166.8 and 279.2%, respectively, with AMF under low P availability, whereas no effect of AMF was found under high P availability. These results have implications for modulating the secondary metabolite production of H. perforatum. However, further studies are needed to evaluate the competition for photosynthates between AMF and flowers at different nutrient availabilities for both plant and AM fungus

SUSTAINABLE PRODUCTION OF FENNEL AND DILL BY INTERCROPPING

Intercropping is claimed to be one of the most significant cropping techniques in sustainable agriculture, and much research and many reviews attribute to its utilization a number of environmental benefits, from promoting land biodiversity to diversifying agricultural outcome. In this sense, intercropping is thought to be a useful means of minimizing the risks of agricultural production in many environments, including those typical of under-developed or marginal areas. In order to validate this hypothesis in a representative area of the semiarid Mediterranean environment, we evaluated the possibility of growing dill and fennel, both belonging to the family Apiaceae, in temporary intercropping. Our trial was performed in Sicily in 2000–01 and 2001–02; in the first year, fennel and dill were cultivated in a mixture using a substitution scheme, whereas in 2001–02 we evaluated the bio-agronomical and chemical features of fennel alone. The biological efficiency of the intercropping system was evaluated by using the Land Equivalent Ratio and the Competitive Ratio, and an estimate of the interaction effects of both crops was performed by analyzing the major vegetative and yield traits of plants, along with the chemical profile of volatiles of the fruits. Both in grain yield and in biomass yield, the most efficient cropping system was the intercropping ratio with a higher proportion of fennel, in which the competitive ratio values calculated for dill reached 1.90 for grain and 2.59 for biomass. Our results also indicate that the presence of dill exerted a clear stabilizing effect on fennel seed yield of the following year: whereas no difference in fennel seed yield was detected from one year to the following on the previously intercropped plots, in the repeated pure stand a 50% yield reduction was recorded. In the trial environment, the technique showed a good potential to improve the efficiency of resource utilization; further long-term experiments will be necessary in order to demonstrate the application of such a technique to other medicinal and aromatic plant mixtures

Crop rotation, nitrogen fertilization and genotype effects on durum wheat productive characteristics

A field trial was performed in 2000/01 and 2001/02 in the experimental farm “Sparacia” (Cammarata – AG – Sicily) in order to evaluate the qualitative and quantitative response of four varieties of durum wheat when grown after a legume crop (field pea) or in rotation with itself and when submitted to different N-fertilization levels: no fertilization (N0, control), 60 kg ha-1 (N 60, rate advised by the EC n. 2078/92 for the Sicilian territory) and 120 kg ha-1 (N 120, fertilization rate commonly used under the “traditional” cropping technique). In the first trial year, the fertilized trial expressed a better yield performance than the control, but in 2001/02, characterized by severe and prolonged dry periods, the effect of crop rotation and variety was shown to be more important

Quality Characteristics of Wholemeal Flour and Bread from Durum Wheat (Triticum turgidum L subsp. durum Desf.) after Field Treatment with Plant Water Extracts

The use of selected plant water extracts to control pests and weeds is gaining growing attention in organic and sustainable agriculture, but the effects that such extracts may exert on the quality aspects of durum wheat are still unexplored. In 2014, 5 plant water extracts (Artemisia arborescens, Euphorbia characias, Rhus coriaria, Thymus vulgaris, Lantana camara) were prepared and distributed on durum wheat cv Valbelice to evaluate their potential herbicidal effects. After crop harvesting, the major physicochemical and technological parameters of wholemeal flours obtained from each treatment were measured and compared with those from chemical weeding and untreated controls. A baking test was also performed to evaluate the breadmaking quality. In wholemeal flours obtained after the treatment with plant extracts protein and dry gluten content were higher than in control and chemical weeding. Wholemeal flours obtained after chemical weeding reached the highest Mixograph parameters, and that from durum wheat treated with R. coriaria extract demonstrated a very high α-amylase activity. We concluded that the treatments with plant water extracts may influence many quality traits of durum wheat. This occurrence must be taken into account in overall decisions concerning the use of plant extracts in pest and weed management practice

Long-Term Field Evaluation of Conventional vs. Micropropagated Plants of Chrysanthemum cinerariifolium

Pyrethrum is a perennial herbaceous plant endemic to the eastern coast of the Adriatic Sea, and introduced in large areas of nearly all continents, where it is cultivated for the industrial extraction of pyrethrins. Pyrethrins are a group of six closely related monoterpene esters, widely used as natural insecticides. The world production of natural pyrethrins is lower than the market demand, and a wider introduction of this crop within the Mediterranean agrosystems could be an appealing opportunity for farmers and manufacturers. The availability of adequate amounts of selected plant material to bring into cultivation is, however, one of the major issues. Therefore, the in vitro propagation of elite pyrethrum genotypes could be a suitable alternative to conventional propagation methods. In this paper, we present the results of a 9-year field comparison between pyrethrum plants coming from an in vitro propagation protocol and plants obtained by cutting from the same mother plants. Furthermore, since plantlets derived from in vitro regeneration may experience ploidy changes, we evaluated the stability of the ploidy level of pyrethrum micropropagated plants by flow cytometry (FCM) analysis. FCM screening revealed no differences among the morphotypes and between them and the mother plant. Likewise, the field evaluation of plants gave no significant differences between flower yields in both groups. Hence, micropropagation was confirmed as an easy, efficient and reproducible method to obtain large quantities of selected pyrethrum genotypes