Forage mixture productivity and silage quality from a grass/legume intercrop in a semiarid Mediterranean environment

In semiarid environments of the Mediterranean region, intercropping is a sustainable agricultural system of long standing. In this area, the pea (Pisum sativum L.) is one of the most commonly grown legume crops. Little information is available on the quality of silages to be obtained from forage mixtures of pea intercropped with cereals or annual grasses. In this study, two experiments were conducted over the course of two growing seasons in Sicily (Italy) with the aim to determine the biomass production of forage crop mixtures and assess, only in the second experiment, the silage quality of grass and legumes. Four cereals and one annual grass species were grown in pure stand and in mixture with pea, and their main agronomic traits were determined. The land equivalent ratio (LER), competitive ratio, and aggressivity index were also calculated. A number of parameters were considered to assess the quality of silage obtained from fermented biomasses derived from pea–ryegrass (Lolium multiflorum Lam. var. Westerwoldicum) intercropping. In the first experiment, the best performance between the intercrops was recorded for the pea–wheat mixture. The total LER calculated for fodder yields was always greater than 1, indicating crop yield advantages ranging from 2.0% to 47.0%. In the second experiment, the pea–ryegrass mixture appeared to respond well, depending on plant arrangement and seeding ratio factors: the ratios 50:50 and 100:50 showed the greatest crop yield advantages, of 12.0% and 11.0%, respectively. All silages revealed a very good suitability of a pea–ryegrass intercropping system with high-quality silage production in the Southern Mediterranean region

Effects of harvesting methods on seed yield and quality of Scorpiurs muricatus L..

Scorpiurus muricatus L. is an annual legume, widely distributed in Mediterranean pastures, that is appreciated by farmers for its productivity, forage quality, and palatability. It is characterised by long flowering and ripening periods and by pod shedding. These characteristics cause high seed losses, which could reduce its seed harvest efficiency in terms of seed yield and quality. In this study, we investigated the effects on seed yield and quality of different harvesting methods (windrowing at different times with subsequent combining was compared with direct combining). Our results show that direct combining when the pods were fully ripened reduced pod losses compared with swathing methods, producing the highest yield of seed actually harvested. However, in this study, the unique climatic conditions during the pod development stage (extremely high temperatures) accelerated the ripening process, presumably limiting pod shedding

Extracting Touristic Information from Online Image Collections

In this paper, we present a Geographical Information Retrieval system, which aims to automatically extract and analyze touristic information from photos of online image collections (in our case of study Flickr). Our system collect all the photos, and the related information, that are associated to a specific city. We then use Google Maps service to geolocate the retrieved photos, and finally we analyze geo-referenced data to obtain our goals: 1) determining and locating the most interesting places of the city, i.e. the most visited locations, and 2) reconstructing touristic routes of the users visiting the city. Information is filtered by using a set of constraints, which we apply to select only the users that reasonably are tourists visiting the city. Tests were performed on an Italian city, Palermo, that is rich in artistic and touristic attractions, but preliminary tests showed that our technique could successfully be applied to any city in the world with a reasonable number of touristic landmarks

Fault Tolerant Ancillary Function of Power Converters in Distributed Generation Power System within a Microgrid Structure

Distributed generation (DG) is deeply changing the existing distribution networks which become very sophisticated and complex incorporating both active and passive equipment. The simplification of their management can be obtained assuming a structure with small networks, namely, microgrids, reproducing, in a smaller scale, the structure of large networks including production, transmission, and distribution of the electrical energy. Power converters in distributed generation systems carry on some different ancillary functions as, for example, grid synchronization, islanding detection, fault ride through, and so on. In view of an optimal utilization of the generated electrical power, fault tolerant operation is to be considered as a suitable ancillary function for the next future. This paper presents a complete modeling of fault tolerant inverters able to simulate the main fault type occurrence and a control algorithm for fault tolerant converters suitable for microgrids. After the model description, formulated in terms of healthy device and leg binary variables, and the illustration of the fault tolerant control strategy, the paper shows how the control preserves power quality when the converter works in the linear range. The effectiveness of the proposed approach and control is shown through computer simulations and experimental results

Wheat yield and grain quality as affected by tillage, sowing time and nitrogen fertilization under rainfed Mediterranean conditions

The research was carried out in 9 sites (5 in 1999-00 and 4 in 2000-01) of inner area of Sicily different for soil type, slope, exposure and preceding crop. The following treatments were studied: (i) conventional tillage and sowing at conventional time (CT); (ii) no tillage and sowing at conventional time (NTc); and (iii) no tillage and early sowing (NTe). In 2000-01 the effect of three nitrogen fertilization treatment (single application at planting, P, and split dressing at two different rates, S and S+) were also evaluated. No tillage systems (NTc and NTe) significantly increased grain yield compared to CT treatment; no differences were observed between the two sowing dates. The productive benefits of no tillage were associated with a decrease of grain protein content that was heavier with early sowing. Regarding N fertilization treatments, S compared with P allowed a significant yield increase; no interaction with tillage technique was found. At the lowest fertilizer rates, split fertilization allowed a significant increase of grain protein content only in NTe

Scorpiurus muricatus L.: an interesting legume species for Mediterranean forage systems

Scorpiurus muricatus L. (prickly scorpion’s tail) is a legume species widely distributed as a spontaneous plant in Mediterranean pastures. In Sicily, farmers ascribe to this species a very high palatability and galactogogue effect, so that its abundance increases the value of the pasture. However, despite its worthy traits, the use of S. muricatus as a forage within cropping systems has not been well investigated. A field experiment was performed during two growing seasons in a semiarid Mediterranean environment to acquire information on the productivity of S. muricatus in comparison with other forage species grown in Mediterranean areas (e.g. berseem clover, burr medic, subterranean clover) and on its response to different cutting managements (cuts made in different phenological stages). Results showed that S. muricatus can provide biomass yield similar to, and in some cases higher than, that of the other forage legumes evaluated, differing from these species in its temporal distribution of the biomass accumulation. The findings contribute to define the role that S. muricatus could play in improving the productivity sustainability of the Mediterranean forage systems

Milk production and physiological traits of ewes and goats housed indoor or grazing at different daily timing in summer

During a 6 week trial in summer, 3 homogeneous groups, each consisting of 5 Comisana ewes and 5 Rossa Mediterranea goats, grazed watered forage resources during day (D) or night (N), or were housed indoor and supplied with mowed herbage(H). Maximum THI peaked at 94 at the end of July, and was almost constantly higher of 80. Milk yield was higher in N than in D and H goats, whereas N ewes produced more milk than H group, but their milk yield was higher than D ewes only in the period with the highest THI values. The lower urea in N goat milk, and the higher casein in N ewe milk, seem to indicate a better efficiency in dietary nitrogen utilization of night grazing animals. N ewes showed lower SCC in milk, and higher incidence of clotting milk samples, in comparison to other ewes. N goats and ewes showed lower rectal temperature and pulse rate in the afternoon and, among metabolic parameters, higher hematic level of sodium. Night grazing was confirmed to be a management practice for increasing heat tolerance, to which goats appeared to be more sensitive in terms of milk yield

Comprehensive Modeling and Experimental Testing of Fault Detection and Management of a Nonredundant Fault-Tolerant VSI

This paper presents an investigation and a comprehensive analysis on fault operations in a conventional three-phase voltage source inverter. After an introductory section dealing with power converter reliability and fault analysis issues in power electronics, a generalized switching function accounting for both healthy and faulty conditions and an easy and feasible method to embed fault diagnosis and reconfiguration within the control algorithm are introduced. The proposed system has simple and compact implementation. Experimental results operating both at open- and closed-loop current control, obtained using a test bench realized using a dSPACE system and the fault-tolerant inverter prototype demonstrate that the proposed solution is effective and feasible and makes all faults easily managed by the controller itself

An IPMSM torque/weight and torque/moment of inertia ratio optimization

In this paper, a torque/weight and torque/moment of inertia ratio optimization procedure for interior permanent magnet syncronous motors (IPMSMs) is presented. More in detail, a performance comparison between several IPMSM rotor structures has been carried out in order to determine the optimum geometry that can maximize the torque/weight and torque/moment of inertia ratios. A commercial motor, with known electrical and mechanical characteristics, has been taken as reference. Its rotor structure has been modified several times, obtaining different rotor geometries and, therefore, many IPMSM models with different electrical and mechanical characteristics. The finite element method (FEM) analysis of each IPMSMs has been performed using the software FEMM, allowing to determine the related torque/load-angle characteristics. From the comparison between the torque/load-angle characteristics of the different IPMSM structures, it can be stated that significant performance improvements can be obtained in dependence not only of the type of permanent magnets and their direction of magnetization, but also of the PM displacement within the rotor