Mariano Fracchiolla

Risk assessment of heavy metal and metalloid toxicity through a contaminated vegetable (Cucurbita maxima) from wastewater irrigated area: A case study for a site-specific risk assessment in Jhang, Pakistan

ABSTRACT The present research was conducted in district Jhang, Pakistan, to evaluate the concentration of metals/metalloids in soil and pumpkin (Cucurbita maxima) irrigated with domestic wastewater. Data revealed that the levels of metals and metalloids in soil samples from two different sites were below the safe limits except Cd, whereas, in the vegetable, the concentrations of As, Se, Ni, Mo, Pb, Mn, and Cu were above the safe limits. The levels of 12 metals and metalloids in the soil were ranged between 0.14 to 22.76 mg/kg at site-I and 0.16 to 22.13 mg/kg at site-II. The levels of these metals in the vegetable were found 0.35 to 61.13 mg/kg at site-I and 0.31 to 53.63 mg/kg at site-II. The transfer factor at both sites was highest for As and Co. The pollution load index recorded for Se, Cu, Cd, Mo, Pb, and Co was greater than 1. The daily intake of As, Mn, and Mo was above the oral reference dose, which reflects that the intake of pumpkin is not safe for the inhabitants of the selected sites. The control measures should be taken to phytoextract heavy metals and metalloids from polluted sites so as to reduce the health risks.

Effects of Mulching Materials on Soil and Performance of cv. Nero di Troia Grapevines in the Puglia Region, Southeastern Italy

The responses in soil conditions, vine growth, and physiological, yield, and composition components of cv. Nero di Troia to the application of synthetic and organic mulches were studied for two years (2006–2007 and 2007–2008). The effects of the application in the vine rows of two synthetic mulches (geotextile as polypropylene and black polyethylene) and an organic mulch (exhausted olive pomace 3- and 6-cm thick) were compared to a control (weed mowing) in an organic vineyard. Throughout the trial, we conducted soil and leaf analyses, weed surveys, and phytotoxicity tests and measured vegetative activity, leaf gas exchange and water status, yield, and composition components. The exhausted olive pomace showed positive effects on some soil fertility variables and on vine physiology (stomatal conductance, transpiration, and net assimilation). Black polyethylene and geotextile provided good control of the weeds, especially in the first year, but positive results were also obtained with the exhausted olive pomace. Yield and composition components of grape were unaffected by any of the organic and synthetic mulches compared to weed mowing. The exhausted olive pomace provided good control of weeds, improved the fertility of the soil, and could be acceptable in terms of sustainability. The mode of action of the exhausted olive pomace was both physical and phytochemical through the release of phytotoxic compounds.

Soil Management Systems: Effects on Soil Properties and Weed Flora

A three-year experiment was conducted in order to evaluate the effects of three different soil management systems in a vineyard (organic mulch with exhausted olive pomace at 6 cm thick, weed mowing and herbicide application) on soil physicochemical characteristics and weed flora. A variety of data was collected throughout the trial, such as soil analyses, weed surveys and phytotoxicity tests. The results show that the exhausted olive pomace was able to increase the K and Mg content and exerted good control over weeds, and also had an effect on the weed flora composition. Although further research is needed, it is possible to conclude that the mode of action of the exhausted olive pomace was both mechanical (thickness of the layer) and phytochemical for the release of phytotoxic compounds (allelochemicals).

Effects of Conservative Tillage and Nitrogen Management on Weed Seed Bank after a Seven-Year Durum Wheat—Faba Bean Rotation

Conservative agriculture includes a range of management strategies with low energy inputs such as no-tillage, minimum tillage, and low application of fertilizers. Weed flora in arable fields is strictly affected by agronomic practices such as tillage and fertilization management. This study was conducted seven years after the beginning of a long-term—durum wheat–faba bean—rotation. It analyzes the combined effects on the soil seed bank of three different tillage systems (conservative, reduced, and conventional tillage) and two levels of nitrogen fertilization. The effects were investigated both using stepwise discriminant analysis and analysis of variance in order to find statistical differences among main factors and their interactions. The seed bank of Conyza canadensis, Papaver rhoeas, Solanum nigrum, Fallopia convolvulus, and Fumaria officinalis was higher in conservative or reduced tillage plots. The magnitude of the response to nitrogen supply varied among weed species. Conyza canadensis seemed to be favored by low nitrogen supply, whereas Sinapis arvensis by higher doses of nitrogen. Anagallis arvensis showed the lowest seed bank in conventionally tilled plots, without distinction of nitrogen supply. The results suggest that different tillage systems and, to a lesser extent, different nitrogen supply, produce changes in the seed bank size and composition, along the soil profile.

Natural compounds with herbicidal activity

Research about phytotoxic activity of natural compounds could lead both to find new herbicidal active ingredients and to plan environmental friendly weed control strategies. Particularly, living organisms could be a source of compounds that are impossible, for their complexity, to synthesize artificially. More over, they could have alternative sites of action respect to the known chemical herbicides and, due to their origin, they should be more environmental safe. Many living organism, such as bacteria, fungi, insects, lichens and plants, are able to produce bioactive compounds. They generally are secondary metabolites or simply waste molecules. In this paper we make a review about these compounds, highlighting potential and constraints.