Francesco Intrigliolo

Effect of long term addition of composts and poultry manure on soil quality of citrus orchards in Southern Italy

A 6-year study was conducted in an organically managed orange orchard located in Sicily (Southern Italy) to assess the effect of compost and organic fertiliser utilisation on soil quality. Adopting a randomised-block experimental design with three replicates, four treatments were carried out. In treatments 1 and 2, two different composts (C1 from distillery by-products and C2 from livestock waste) were applied. The plots of treatment 3 were fertilised using dried poultry manure. The control treatment was fertilised by mineral/synthetic fertilisers. In order to verify the hypothesis that composts and organic fertilisers improve soil fertility, soil quality was evaluated by selecting dynamic soil parameters, as indicators linked to C and N cycles. Total organic C, total N, C/N ratio, humified fraction, isoelectric focussing (IEF) of extracted organic matter, microbial biomass C, potentially mineralisable N under anaerobic conditions, potentially mineralisable C, C mineralisation quotient and metabolic quotient were determined for each sample. Moreover, the Community Level Physiological Profile (by Biolog technique) was defined, calculating derived functional biodiversity and versatility indexes. Parameters related to IEF and potentially mineralisable C showed significant differences among the treatments. Moreover, total C, total N and humification parameters tended to increase, while no differences were observed in biodiversity indexes. On these findings, it was concluded that composts and poultry manure only weakly affected soil properties, though they increased soil potentially available nutritive elements to crops.

Evaluation of Organic Matter Stability During the Composting Process of Agroindustrial Wastes

Composting of wastes from citrus industrial processing (pastazzo and sludge) was studied in order to evaluate the evolution of organic matter during the process and to individuate chemical and/or biochemical techniques able to set the stability of the final product. Composts from two open-air piles of different composition were sampled every month during the whole period of composting (5 months) and the organic matter of each sample was characterised by chemical and biochemical techniques. Humification rate (HR%) and humification index (HI) were determined. Extracted organic matter of the six samples collected for each compost was investigated by isoelectric-focusing technique (IEF). The biochemical analysis were based on the study of C-mineralisation after the addition of each collected sample to soil. Results obtained clearly demonstrated organic matter evolution during composting processes. Humification rates increased and humification indexes decreased over time, while extracted organic matter showed electrophoretic behaviour typical of stabilised organic compounds. Moreover, mineralisation patterns confirmed the increased level of organic matter stability during the composting process.

Study of Organic Matter Evolution in Citrus Compost by Isoelectrofocusing Technique

Three composts from citrus-processing industry wastes, sampled at prefixed times during the composting process, were studied with the aim to follow the organic matter evolution by using the isoelectrofocusing (IEF) technique. Results indicated that IEF qualitative analyses allowed evaluation of the organic matter transformation during composting process, showing a decrease of IEF peaks focused at lower values of pH (less stabilized organic matter) and a corresponding increase of peaks focused at higher value of pH (more humified material). The parameter A %, defined as the areas sum of IEF peaks focused at pH>4.7, could be considered particularly effective as a “threshold value” to evaluate the level of organic matter evolution for the considered composts.

Nutritional response of Zea mays L. seedlings to “on plant demand” fertilizer: A vector analysis approach

ABSTRACT Glass matrix based fertilizers (GMF) are new mineral fertilizers, able to release nutrients on the basis of plant demand: they are soluble only in metal complexing solutions, such as those exuded by plant roots. Moreover, nutrient release could be increased by mixing the glass-matrix fertilizer to different organic biomasses, such as leather meal, digested vine vinasse, etc. A greenhouse pot experiment was conducted for assessing the effect of an organo-mineral fertilizer, obtained by mixing GMF with increasing percentages of digested vine vinasse [DVV, at 5% (GMF95), 20% (GMF80) and 50% (GMF50) w/w], on the root and shoot biomass and nutritional status of Zea mays L. seedlings. Among tested fertilizers, the formulations GMF80 and GMF50 gave the best results as shoot/root ratio. The treatments with GMF, GMF95 and GMF80 gave rise to a significant increase of both shoot and root biomass and a tendency to increase the macro and micronutrients availability.

Non-destructive Proximal Sensing for Early Detection of Citrus Nutrient and Water Stress

This chapter reports the application of non-destructive optical-based technologies for the rapid and efficient assessment of the nutritional status and water stress detection improving their use efficiency. In the proximal sensing section, it was presented the use of spectral and hyperspectral imaging to evaluate the plant nutritional status. Proximal sensing offers the opportunity to rapidly collect a huge amount of crop canopy information. In the infrared thermography and thermometry section, results about their use to assess plant water stress analysing canopy and soil temperature variation were reported. Finally, the use of spectrophotometry and of the chlorophyll meter for the citrus nutrient detection is presented. The analyses of data were carried out by linear regressions and by multivariate statistics.

Organic Citrus: Soil Fertility and Plant Nutrition Management

During the last decade, the organic food and farming (OFF) sector has grown considerably worldwide. Citrus play an important role in organic farming systems, being one of the most highly demanded products on the market for organic produce. In this chapter, the criteria for citrus orchards fertility management and plant nutrition in the organically managed agroecosystems are discussed in the light of the most relevant scientific literature. Moreover, two case studies carried out in Southern Italy and aimed at comparing conventional and organic orange management in terms of yield, yield quality and long-term impact on soil fertility are reported. The body of knowledge available and the results presented demonstrate that organic citrus management is a technically feasible option for citrus growers. In addition, the shift to organic farming could contribute to enhance the environmental sustainability of citrus productions in the long term.

DEFICIT IRRIGATION STRATEGIES: PRELIMINARY ASSESSMENT ON A SICILIAN YOUNG ORANGE ORCHARD

In Mediterranean regions the economical sustainability of fruit tree crops strictly depends on the limited availability of water resources. Deficit irrigation (DI) strategies are particularly suitable to optimize water resource, improve water use efficiency by reducing crop water requirements. In the study, DI strategies were adopted on a young orange orchard in Sicily (Southern Italy) and crop physiological features were monitored and analysed for possible negative effects. The orchard includes 300, 4-years old, trees, irrigated with drip and sub-drip irrigation systems. Four irrigation strategies (replicated 3 times), based on DI concepts, were adopted, each supplying different percentages (50, 75, 100%) of the irrigation requirement (IR). IR values were calculated via the Penman-Monteith model, by assuming a crop coefficient (Kc) of 0.45 typical for immature orchard, and correction coefficients accounting for the localized irrigation. Several physiological indices were measured during the trial, including Leaf Area Index, stem water potential, canopy temperature, and trunk diameter, among others. Preliminary observations, obtained during the two irrigation periods (2011-2012), evidenced slight variations of xylematic potential and stomata conductance among the monitored treatments. LAI, canopy volume and trunk circumference increases were quite similar among treatments. Accordingly, trees growth seems to sustain the imposed water restrictions, without significant stress symptoms on the analyzed physiological features.