Journal of Agricultural Engineering 2019-08-23T16:07:08+02:00 Paola Granata Open Journal Systems <p>The <strong>Journal of Agricultural Engineering (JAE)</strong> is the official journal of the <a href="" target="_blank" rel="noopener"><strong>Italian Society of Agricultural Engineering</strong></a> supported by University of Bologna, Italy. The subject matter covers a complete and interdisciplinary range of research in engineering for agriculture and biosystems.</p> Flow resistance of partially flexible vegetation: A full-scale study with natural plants 2019-08-23T16:07:07+02:00 Enrico Antonio Chiaradia Claudio Gandolfi Gian Battista Bischetti <p>Riparian vegetation plays a crucial role in riverine ecosystems, providing many types of benefits to nature and humanity. However, a high vegetation density can reduce the conveyance capacity of a watercourse, particularly in the case of shrubs, which are very common within riverbeds and widely used in river and channel restoration works. In this paper, we study the influence of three species of shrubs (white and goat willows and black alder) on the hydraulic resistance factor of a real-scale channel under controlled flow conditions. A system for the anchorage of shrubs to the channel bed allowed us to carry out repeated experiments with the three plant species and with varying plant densities and flow rates. The experimental results provided a range of values for the additional contribution of the vegetation to the hydraulic resistance factor from 0.004 to 0.071 m<sup>–1/3</sup>s, in terms of Manning’s coefficient. This variability is related to the vegetation setup (plant species and density) but also to the increasingly hydrodynamic configuration assumed by plants at higher flow velocities and submergence ratios. We found that these factors can be summarised quite effectively by the product of elasticity (E), plant density (M), and plant area index (PAI). At small (E∙M∙PAI) values (&lt;10<sup>8</sup>) the resistance coefficient is less than 0.01, while it increases of up to one order of magnitude when (E∙M∙PAI) exceeds 10<sup>10</sup>. Furthermore, our results show a distinct two-stage trend of the value of the additional contribution to the n coefficient of a given vegetation setup at varying velocities and submergence levels, with values decreasing when a threshold of velocity and submergence ratio is exceeded. The position of this threshold point appears to be related to the geometrical and mechanical characteristics of the plants. Although our experiments do not provide enough data to identify a functional relationship between n and specific characteristics of the plants and of the flow, they show that the effect of shrubs on hydraulic resistance is highly variable with the flow conditions and that the conveyance capacity may be significantly larger than expected.</p> 2019-06-25T09:41:35+02:00 ##submission.copyrightStatement## Report on earthquake-induced failures of rural buildings aimed at future preservation strategies 2019-08-23T16:07:07+02:00 Marco Bovo Alberto Barbaresi Daniele Torreggiani Patrizia Tassinari <p>The rural landscape is undergoing rapid changes, and catastrophic events, such as earthquakes, can speed up this mutation, bringing to a loss of its traditional signs. In May 2012, two strong seismic events hit the Emilia Romagna region, in northern Italy. Those earthquakes caused several damages and collapses to historical rural buildings, highlighting their high seismic vulnerability. In this paper, damages and collapses collected in the aftermath surveys on 22 rural historical buildings, are presented and commented. It was observed that in the area hit by the earthquake few recurrent typologies are present, and buildings of the same typology showed similar damage mechanisms. Therefore, in order to define the most typical damages affecting rural constructions, the building stock has been classified in different categories, based on plan distribution and intended use of each building. The first criterion suggests considering isolated and composed buildings. The second separates the structures in dwellings for residential use, stable-haylofts and buildings used for other minor services. The outcomes presented in this paper allowed to identify the rural building typologies most vulnerable to earthquakes and to define recurring deficiencies for the various categories. In general, the main reasons of the collapses can be ascribed to lack of effective connections between orthogonal walls, poor connections between floor elements and walls, and excessive flexibility of floor diaphragms.</p> 2019-06-25T00:00:00+02:00 ##submission.copyrightStatement## Deducing the stage-discharge relationship for contracted weirs by the outflow theory of Malcherek 2019-08-23T16:07:06+02:00 Vito Ferro Ismail Aydin <p>The aim of this paper was the deduction of a new stage-discharge relationship for a contracted weir, having a crest length less than the channel width, by using the Malcherek’s outflow theory. The average outflow velocity over the rectangular contracted weir was expressed in terms of the head over weir, the momentum correction coefficient and the ratio between the crest length and the channel width. This theoretically deduced stage-discharge formula was calibrated by measurements carried out for values of the ratio between the crest length and the channel width ranging from 0.3125 to 0.9375. In particular, a relationship to estimate the momentum correction coefficient for contracted weirs was deduced. The analysis showed that the proposed stage-discharge relationship is characterised by an excellent performance and allows to measure discharge values characterised by errors which are, for 96.0% of the measured values, less than or equal to ±5%.</p> 2019-06-25T09:57:38+02:00 ##submission.copyrightStatement## Assessing the impacts of climate change on dependable flow and potential irrigable area using the SWAT model. The case of Maasin River watershed in Laguna, Philippines 2019-08-23T16:07:08+02:00 Lanie A. Alejo Victor B. Ella <p>Seasonal changes in rainfall and temperature brought about by climate change affect water resources availability for rice production areas. There are currently no published applications of the soil and water assessment tool (SWAT) model on quantified effects of climate variability on irrigation service areas for rice production. The study assessed the impacts of climate change on dependable flow and potential irrigable areas of the Maasin River in Laguna, Philippines. Projected variations of rainfall and temperature in 2020 and 2050 developed using PRECIS model based on special report on emission scenarios were employed. The SWAT model was then used to simulate stream flow for each climate change scenario, from which dependable flows were quantified using flow duration analysis. Diversion water requirements for the rice areas in the watershed were determined using CROPWAT. Based on dependable flows and irrigation demand, the potential irrigable areas were estimated. Calibration and validation of the SWAT model showed satisfactory performance in stream flow simulations. The dependable flow in irrigation systems may decline by more than 50% in 2020 and by as much as 97% in 2050, because of seasonal changes in rainfall. In effect, the potential irrigable area may decrease to less than half of the current service area depending on the level of greenhouse gases emissions. SWAT water balance projections suggest surface runoff during wet seasons and increase annual groundwater recharge are possible sources of supplemental irrigation. Provisions of suitable storage reservoir facilities and groundwater development projects will alleviate water scarce conditions. The study demonstrated a technique that may be applied in other irrigation systems in the Philippines and in other countries to quantify the effects of climate change on dependable flows and potential irrigable areas. It can serve as an input to water resources planning and policy recommendations for climate change adaptation and risk reduction strategies. This technique can also be used to assess water resources in other perennial rivers and its viability for the development of new irrigation systems in the Philippines.</p> 2019-06-05T00:00:00+02:00 ##submission.copyrightStatement## Agrochemical plastic packaging waste decontamination for recycling: Pilot tests in Italy 2019-08-23T16:07:05+02:00 Caterina Picuno Zoe Godosi Kerstin Kuchta Pietro Picuno <p>Agriculture, one of the main economic pillars in Europe, plays a growing important role towards the environmental sustainability of the extra-urban land, in which the agricultural activities may proactively contribute to control and regulate the whole ecological conditions. Modern agriculture currently needs big quantities of agrochemicals, which are necessary for the growth and protection of crops and animals. These agrochemicals are commercially distributed to consumers in many types of containers. The most widely used packaging solutions usually employ plastic materials (<em>e.g</em>., containers for liquid pesticide; sacks for granular fertiliser; <em>etc</em>.). These materials, after the use of the agrochemical, need to be decontaminated, before being entrained in a recycling process, in the framework of a circular economy. In the present paper the main results coming from a EU-funded international project are reported, with specific reference to a pilot station that was realised in Italy with the aim to implement and test a codified system for the decontamination of these plastic containers for agrochemicals. The experimental tests were supported by relevant laboratory analysis, which have confirmed that the triple-rinsing decontamination procedure - traditionally employed by farmers for washing and decontaminating these containers - may be effective only under some well-defined conditions. Triple rinsing by farmers has indeed led to an only partial decontamination of the plastic containers, if farmers did not follow an appropriate triple-rinsing protocol, or did not triple-rinse the containers immediately after their emptying.</p> 2019-06-25T10:07:54+02:00 ##submission.copyrightStatement##