Laura Bacci

Root Zone Sensors for Irrigation Management in Intensive Agriculture

Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy.

Laboratory and outdoor assessment of UV protection offered by flax and hemp fabrics dyed with natural dyes.

The safest protection from UV radiation (UVR) exposure is offered by clothing and its protectiveness depends on fabric composition (natural, artificial or synthetic fibers), fabric parameters (porosity, weight and thickness) and dyeing (natural or synthetic dyes, dye concentration, UV absorbing properties, etc.). In this study the UV protection properties of two fabrics made of natural fibers (flax and hemp) dyed with some of the most common natural dyes were investigated. UVR transmittance of fabrics was measured by two methods: one based on the utilization of a spectrophotometer equipped with an integrating sphere (in vitro test), and the other based on outdoor measurements taken by a spectroradiometer. Transmittance measurements were used to calculate the ultraviolet protection factor (UPF). Experimental results revealed that natural dyes could confer good UV protection, depending mainly on their different UVR‐absorbing properties, provided that the fabric construction already guaranteed good cover. An increase in cover factor caused by the dyeing process was also detected. Weld‐dyed fabrics gave the highest protection level. The comparison between the two methods applied to measure fabric transmittance pointed out that the UPFs calculated by in vitro measurements were generally lower than those based on outdoor data, indicating an underestimation of the actual protection level of tested fabrics assessed by the in vitro test.

Effect of different extraction methods on fiber quality of nettle (Urtica dioica L.)

Chemical extraction, water retting, microbiological and enzymatic methods were applied on entire nettle stalks and/or unretted decorticated fiber of a selected fiber nettle clone. Morphological and mechanical properties and chemical composition were then determined on fiber samples. The first interesting result concerned the good degree of separation between fibers and shives obtained by mechanical scutching applied on stalks stored for 1 year, probably resulting from natural retting processes occurring during the storage. Microbiological retting (anaerobic plus aerobic bacteria) of entire stalks and/or unretted decorticated fiber produced fibers with a higher quality than water retting. Both enzymes used (Viscozyme ® L and Pectinex® Ultra SP-L), improved fiber quality if EDTA was added. The enzyme vat retting gave good results on both water-retted fibers and unretted decorticated fibers, while the spray enzyme treated fibers usually displayed thicker diameter, lower cellulose content and, for Viscozyme ® L, lower strength values, without differences between the two storage methods used after enzyme application.

Sensory evaluation and instrumental measurements to determine tactile properties of wool fabrics

Fabrics manufactured in Italy with 100% Sardinian sheep breed wool, traditionally named ‘Orbace’, and with local Tuscan wool from 50% Sardinian and 50% Comisana sheep breeds wool (Tuscan Cloth), were subjected to sensory evaluation, through descriptive analysis performed by a trained panel, and to an instrumental evaluation method, through FAST – Fabric Assurance by Simple Testing. The correlation between instrumental data and sensory attributes was investigated. Sensory evaluation indicated that Orbace fabrics, originated from 100% Sardinian wool, had higher grittiness, stiffness, force of compression and hand friction and lower softness and tensile stretch, as compared to the fabrics obtained from mixed wool. Principal component analysis (PCA) indicated a high correlation for grittiness, stiffness and force of compression in one direction, tensile stretch, softness, warmth and fullness in the opposite, clearly discriminating in this dimension Orbaces from Tuscan fabrics. This discrimination appears to be an effect of the wool used for the different fabrics. Differences in key sensory traits were also recorded among fabrics derived from the same raw material, but differing in weave. Thickness, as the key attribute of the second PCA dimension, provided discriminations within groups and is reasonably perceived as an effect of different weaves. Canonical Correlation Analysis indicated that measurements performed with FAST were correlated with a number of basic touch traits, including softness, stiffness, force of compression and tensile stretch. Orbace and Tuscan Cloth handle definition, on the basis of sensory and instrumental measures, will be of use to describe and protect original products.

Effects of sowing date and nitrogen fertilization on growth, development and yield of a short day cultivar of millet (Pennisetum glaucum L.) in Mali

The effects of different nitrogen supplies on the performance of the short-day cultivar M9D3 of pearl millet (Pennisetum glaucum L. R.Br.) and their interaction with sowing time were analysed in a two-year experiment in Mali. The first sowing dates coincided with the beginning of the rainy season. The second sowings were 20 days later. The sowing date affected only the emergence-earing duration independently of nitrogen application. The linear reduction in straw yield, caused by the shortening of the cycle, was not combined with a reduction in grain yield. The application of even low levels of nitrogen to millet crops always increased the grain yield, as a consequence of a higher number of productive panicles, while the straw production was positively affected only when the rainy season started early. The non-agreement between the high productive potential of the first sowing crops and their grain yield, in comparison with the plants of the second sowing date, could be ascribed, first of all, to the more marked asynchrony between the time corresponding to LAImax and the grain filling phase, characterised by the maximum sink demand and, second, to a longer time interval during which stem growth and panicle growth are in direct competition.

Evaluation and adaptation of TOMGRO model to Italian tomato protected crops

Abstract A simplified version of TOMGRO, a well-known model for tomato growth simulation, was delivered by its authors in 1999, with the aim to adapt the program to operational exigencies. This model version was chosen to integrate the functions of a decision support tool, oriented to support Italian tomato growers in soilless crop fertigation management. During the preliminary evaluation phase, its application on data collected in three greenhouse experiments conducted on tomato cv. Jama in Pisa (central Italy) in 2004 and 2005, showed an insufficient accuracy in the Leaf Area Index (LAI) estimation of tomato crops. Consequently, node number and LAI computational algorithms were modified. This paper discusses model modifications, analysing their effects on tomato growth simulation. In comparison with the observed data, the modified model showed a good enhancement of estimation accuracy of node and LAI, with significantly positive effects also on plant and fruit biomass estimation.

A Preliminary Characterization of Wools from Italian Native Sheep Breeds: Opportunities for New Productions and the Development of Rural Areas

Italian sheep breeds, either local or native, produce about 14,000 tons of greasy wool per year included in the range of moderate to poor quality wools. In order to exploit neglected local textile resources, this study focused on a preliminary descriptive analysis of wools from some Italian native sheep breeds by measuring diameter and length of wool fibers. Variability emerging from data was described using multivariate techniques. A graphic description of different wools was provided by applying cluster analysis in order to distinguish wool characters by sheep breeds and clearly identify wool groups according to fiber variables.

Neglected Wools: Fundamental Steps to Counteract the Loss of Potentially Valuable Materials Derived from Native Sheep Breeds

In order to enhance the textile value of Italian native and local wools, research projects were carried out by starting mapping wools from some Italian sheep breeds through a preliminary morphological characterization of wool fibres. Furthermore, textile processing procedures differing from the commonly used woolling techniques have been set up. The results have shown that, at national level, native and local wools, beyond being more widely employed in the carpets production, could be also used in the higher added value sector of clothing and fashion.

An electronic instrument for the measurement and recording of leaf angles

Abstract Research in the last decades has shown the importance of the geometry of vegetation in defining the radiative regime within a crop canopy. Accordingly we have devised an electronic instrument to allow fast and accurate measurement of the angles of elevation, midrib azimuth and twist of leaves and branches. The measurement range of the instrument is 180° for elevation, 360° for azimuth and 120° for twist, with an accuracy of 2° and 1° for the last measurements, respectively. The accuracy of elevation measurements is 1° in the - 45°/+45° range and 3° in the remaining intervals. The stored data can be transferred to a personal computer using specially developed software that allows either the construction of numerical files in standard ASCII format or an initial processing into angular classes of variable width. The instrument is relatively inexpensive and provides acceptable accuracy and rapid execution, allowing the collection of the large data sets necessary for an exact description of the geometry of a crop.

Modelling Evapotranspiration of Container Crops for Irrigation Scheduling

Irrigation is now recognized as an important component in the agriculture economy of Mediterranean regions. As practiced by many growers, it is often based on traditional application methods that fail to measure the supply of water needed to satisfy the variable requirements of different crops. In order to achieve more profitable and sustainable cropping systems, it is essential to modernize existing irrigation systems and improve irrigation water use efficiency (WUE). Up-to-date methods of irrigation should likewise be based on sound principles and techniques for attaining greater control over the soil-cropwater regime and for optimizing irrigation in relation to all other essential agricultural inputs and operations. Accurate predictions of crop water requirements are necessary for an efficient use of irrigation water in container crops cultivated both outdoors and in greenhouse. Irrigation scheduling (IS) has conventionally aimed to achieve an optimum water supply for productivity, with soil or container water content being maintained close to field capacity. Different approaches to IS have been developed, each having both advantages and disadvantages but despite the number of available systems and apparatus, not entirely satisfactory solutions have been found to rationalize IS, assuring optimal plant growth with minimal water use (Jones, 2004). Many growers, especially in the Mediterranean regions, use simple timers for automated irrigation control of containerized crops and scheduling is based on their own experience. Evapotranspiration (ET) is the primary process affecting crop water requirements and, therefore, its knowledge is essential for efficient irrigation management. ET is the combined process of evaporation from soil or substrate and leaf transpiration. Evapotranspiration requires two essential components: a source of energy and a vapour transport mechanism. Energy is needed for phase change from liquid to vapour in sub-stomatal cavities whereas the leaf-to-air vapour pressure gradient ensures that water vapour crosses leaf stomata. In container-grown plants, ET is affected by many factors, both environmental (e.g. air temperature, radiation, humidity, wind speed) and plant related characteristics (e.g. growth