Effect of leguminous cover crops on soil biological activity in pots of Citrus unshiu Marcovitch

Little is known about the effects of cover crops on soil properties in citrus orchards. To fill this gap, this work was aimed to determine the effects of leguminous cover crops on the chemical and biological properties of the soil and on the structure of the microbial community in pots of Citrus unshiu (Marcovitch). After amendment with cover crops, an increase in total organic C (TOC), total extractable C (TEC), and total N (TN) contents were observed irrespective of the type of soil. Substrate induced respiration (SIR), and potentially mineralisable nitrogen (PMN), tested three times in one year, were higher in soils with leguminous cover crops while no significant differences were observed in protease and deaminase activity. The effect on the chemical and biochemical properties of the soil was more evident in plots containing Trifolium subterraneum. No changes were observed in the microbial communities studied (_-proteobacteria, _-proteobacteria, nitrogen-fixing, and ammonia oxidizers) irrespective of the kind of cover crop or type of soil, neither were variations noted during the trial

Produzione, qualità e analisi della filiera produttiva del lino da fibra in Italia

Fibre flax (Linum usitatissimum L.) is disappeared from the ltalian crop systems, while the textile industry has reached a leading position. The reintroduction of the crop is than potentially promising but the crop techniques and the production processes have to be set up. In 12 environments: crop development and growth, cultivar response, straw, fibre and seed yields, and fibre quality were analysed in the 1992-98 period. The data pointed out crop cycles of 176 and 110 d for the autumn and the spring sowing time respectively, corresponding to 1125 and 990°C d cumulated growing degree. Straw yield at pulling was on average of 6.3 t ha-1, with relevant differences among years and environrnents. Early maturity cultivar yielded more in the less favourable sites. N fertilization was occasionally relevant, and a generally distributions of 60 kg N ha-1 was the more effective. In the Mediterranean environments, with the autumn, sowing flax was more productive and the yield steady. The long fibre ratio was often low (10-13%) and the quality uneven because of the insufficient cleanliness due to retting difficulties. Occasionally, the value of the fibre was affected by the insufficient stem length. In the less dense crop, the seed yield was on average 0.9 t ha-1. Such productions were similar to those assessed for the more dense crop. In conclusion: because of the complexity of the interactions among the crop growth, the yield, the retting process and the fibre quality flax reintroduction is doubtful. In the production processes retting seems to be the crucial phase. Il lino da fibra (Linum usitatissimum L.) è da tempo assente negli ordinamenti colturali italiani, mentre è assai importante l'industria di filatura. La reintroduzione della coltura appare quindi potenzialmente promettente, ma richiede la messa a punto dell'agrotecnica e della filiera produttiva. Nel periodo 1992-1998 in 12 ambienti sono stati esaminati: lo sviluppo e la crescita della coltura, l'adattamento di cultivar, la produzione di paglia, fibra e seme, la resa alla stigliatura, la qualità della fibra. I dati raccolti evidenziano cicli colturali in media di 176 e 110 d rispettivamente per le semine autunnali (ambienti del centro-sud) e vemino-primaverili; corrispondenti a somme termiche di 1125 e 990°C d. La produzione di paglia alla estirpatura è stata in media di 6.3 t ha-1 con valori assai variabili tra annate e ambienti. Le varietà a ciclo corto sono apparse migliori nelle condizioni difficili. L'effetto della concimazione azotata è apparsa talvolta rilevante e comunque con dosi ottimali prossime a 60 kg ha-1 di N. Negli ambienti del centro-sud le semine autunnali si sono dimostrate spesso le più interessanti e sicure. La resa in fibra lunga è stata bassa (10-13%) e la qualità variabile per la scarsa pulizia dovuta alle difficoltà di macerazione. La modesta lunghezza tecnica dello stelo sovente riduce il valore del prodotto. In coltura rada, la produzione di seme è variata da 0.5 a 1.5 t ha-1; tali valori non si sono discostati in modo apprezzabile da quelli ottenuti in coltura fitta. In conclusione, la diffusione del lino appare problematica per le complesse interazioni tra la produzione, il processo di macerazione e la qualità della fibra. Soprattutto la macerazione appare il passaggio chiave

Tissue engineering for the development of threedimensional in vitro models of human mucosae

The recent progress in the biomaterials field and the need for novel 3D cell culture models has led us to develop a new model, the 3D mucosal outgrowth, with advanced characteristics: the simultaneous presence of two differentiated cytotypes (a polarized epithelium above a fibroblastic layer), a complex extracellular matrix (ECM) and the possibility for long-term exposures. This model can be used to grow different human mucosae in vitro, with two types of support scaffolds, a porous polyethylene terephthalate (PET) membrane, for which the model was initially developed, and a poly-L-lactide (PLLA) membrane that was later adapted to the model due to its biodegradability. A fragment of the tissue of interest is placed on the membrane and embedded within a synthetic extra cellular matrix; during the culture period, cells start to grow outwards from the central biopsy and form a new mucosa. Outgrowths grown on PET and PLLA were characterised morphologically by electron microscopy, and immunotyped by immunofluorescence and immunohistochemistry. When grown on PET, all tested mucosae (bronchial, oral and colorectal) showed good differentiation of the relevant cytotypes and proper organization of the ECM. For this reason, they were used for functional studies. Outgrowths developed on PLLA instead, showed a lower degree of cell differentiation and a tendency to form tubular growths that stained positively for endothelial markers. Further evaluations are needed to verify the possibility to use PLLA as a support scaffold for this model

Industrial orange waste as organic fertilizer in durum wheat

Nowadays agro-industrial waste induces increasing problems due to the high economic cost and heavy environmental impact of disposal. By contrast, its potential re-use as organic fertilizer could represent a sustainable approach to recycling nutrients and reintegrating organic matter into soil. Such recycling should be particularly beneficial in Mediterranean areas because there is a progressive loss of soil fertility. To assess the possible re-use of industrial citrus waste as organic fertilizer, a two-year research project was carried out to study the effects of dried orange waste on the growth and production of durum wheat (Triticum durum Desf.). Two dried orange waste doses of 4 and 8 kg/m$^{2}$ were compared with conventional mineral fertilization, of 80 kg/ha$^{2}$ of nitrogen, and with a control without fertilization in the first year. During the second year, the residual effects of the past year's fertilization and two-year application of the orange waste doses and mineral fertilization on duration of biological cycle, grain yield, leaf area index, above-ground biomass and crop growth rate were studied. Our results show that organic fertilization gave similar wheat yields to the mineral fertilization, averaging at 3.63 t/ha. Organic fertilization promoted crop growth much more than mineral fertilization, by up to +400%. However, at the highest dose repeated organic fertilization induced a severe depressive effect on crop establishment. It indeed gave the lowest values for leaf area index of 0.6, biomass of 222 g/m$^{2}$ dry weight and crop growth rate of 2.5 g m$^{-2}$ d$^{-1}$ at the heading stage, and a 50% decrease in wheat grain yield. In both years, the lowest dose of orange waste produced maximum agronomic efficiency. We conclude that an appropriate use of dried orange waste as fertilizer can partially solve environmental problems related to the citrus fruit processing industry, and represents a low cost organic matter source for Mediterranean soil with poor fertility

Lupin Seed for the Crop-Livestock Food Chain

The ban on animal protein supplements in animal nutrition and, particularly, the increase in the demand for alternative protein sources to replace soybean meal in organic farming has stimulated research on GM-free feeds and renewed interest in grain legumes. Of these lupin appears to be one of the more interesting and promising crops for ruminant diets, due to its key role in low-input cropping systems and its high protein content. The aim of this study was to evaluate the productive and nutritional characteristics of several sweet varieties of lupin seeds cultivated in the Mediterranean region. The trial was carried out during the years 2007/08 on a volcanic soil in East Sicily, employing 8 sweet cultivars belonging to Lupinus albus, L. angustifolius and L. luteus species. Yield and its components (pod plant-1, seed pod-1, 1000 seed weight) were evaluated. Crude protein, fibre fractions and alkaloid content were also determined. L. albus exhibited the highest yields (2.2 t ha-1), with an intermediate value of pod x plant (15.4). L. luteus yielded 1.5 t ha-1 and L. angustifolius 0.5 t ha-1. L. luteus showed higher levels of crude protein (34.2%) although the greatest protein yield per hectare was recorded in L. albus (0.7 t ha-1). L. angustifolius showed the highest mean values of NDF (28.1%) and ADF (25%), whereas L. luteus the lowest mean values of ADL (1.75%). Six alkaloids were detected and quantified, among which, the Iso-lupanine always was the most abundant (1.5 mg 100g-1, on average). Lower concentrations of quinolizidine were observed in L. luteus (0.9 – 1.4 mg 100g-1) as compared with L. angustifolius (1.5 – 5.5 mg 100g-1) and L. albus (3.8 – 7.5 mg 100g-1). Alkaloid content was always lower than the safe limit of toxicity (< 0.20‰) indicated for human and animal consumption

The effect of fire on the dormancy break of annual legume seeds

Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm) and subjected to fires at two different intensities (high and low). As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C) for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50%) remained non-germinated in the soil

The effect of fire on the dormancy break of three annual legume seeds

Fire is a common phenomenon in the Mediterranean environment and strongly influences vegetal population dynamics through its impact on vegetation and the soil seed bank. Fire is able to break down the seed coat of hard-seeded legumes within the soil and trigger germination. To evaluate the effect of fire on the dormancy break in Medicago ciliaris, Medicago rugosa and Scorpiurus muricatus subsp. subvillosus, the seeds were placed at three different depths (surface, 25 mm and 50 mm) and subjected to fires at two different intensities (high and low). As a control sample, a batch of seeds was buried at 25 mm for the duration of the trial and not subjected to fire. Soil temperatures during the fire were compared directly to stubble quantity and indirectly related to soil depth. The two Medicago species survived exposure to 90°C for a few minutes and displayed a significant increase in germination with exposure to high temperatures (over 70°C) for several minutes. On the other hand, no germination occurred in Scorpiurus, irrespective of treatment. In conclusion, fire had a significant and positive effect in triggering germination of the Medicago species, but the dispersal strategies of these hard-seeded legumes are only partially interrupted by fire as a large number of seeds (>50%) remained non-germinated in the soil