Search results for "Monoculture"
showing 10 items of 20 documents
Screening of microalgae and LED grow light spectra for effective removal of dissolved nutrients from cold-water recirculating aquaculture system (RAS…
2019
Popularity of recirculating aquaculture systems (RAS) is increasing. Because of the high water recirculation rate, dissolved nutrients originating from fish feed are concentrated enough in RAS wastewater (WW) to enable growth of primary producers, e.g. microalgae. This study evaluated nitrate-nitrogen (NO3-N) and phosphate-phosphorus (PO4-P) removal efficiency of ten temperate zone freshwater microalgae species during their exponential growth phase in unfiltered RAS WW at 17 ± 0.5 °C. Growth and nutrient uptake efficiency of six green and four non-green microalgae strains were compared between WW and reference growth medium in batch monocultures. The effect of three different LED grow light…
Mixed Function Oxidase Activity and Organochlorine Levels in Farmed Sharpsnout Seabream (Diplodus puntazzo) from Two Intensive Aquaculture Facilities
2004
Mixed function oxidase (MFO) activities and organochlorine levels were investigated in liver of farmed sharpsnout seabream bred in two intensive facilities, a sea farm and a land-based farm. The aim of this study is to investigate how different facility locations and breeding conditions might affect fish metabolic capabilities and accumulation of toxic chemicals in farmed sharpsnout seabream. The differences between breeding two or more fish species in the same cage or tank known as polyculture, and monoculture (1 species) were also investigated. The results showed that both facility location (sea and land) as well as breeding systems (polyculture and monoculture) might be responsible for t…
Long-term effects of contrasting tillage systems on soil C and N pools and on main microbial groups differ by crop sequence
2021
Abstract Determining the best conservation agriculture practices for increasing soil organic carbon (C) and hence soil quality is of paramount importance in the semi-arid Mediterranean environment, where soils are experiencing a continuous decline in organic matter. Therefore, the aim of this long-term study was to assess the combined effects of tillage system and crop sequence on soil organic C and biochemical properties of soil generally used as indicators of soil quality. After 23 years of continuous application of contrasting tillage systems (conventional tillage [CT], vs. no tillage [NT]) and crop sequences (wheat monoculture vs. wheat-faba bean rotation), soil samples were collected f…
Research focusing on plant performance in constructed wetlands and agronomic application of treated wastewater – A set of experimental studies in Sic…
2019
Constructed wetlands are sustainable technologies for the treatment of wastewater. These biological systems have been widely studied throughout the world for more than 30 years; however, most studies have focused on the effects of design and engineering on pollutant removal from wastewater. Undoubtedly, agro-technical aspects have been given too little consideration by research. This paper reports the main results of a set of experiments carried out on two pilot horizontal subsurface flow systems in Sicily (Italy). Festuca, Lolium and Pennisetum spp. in combination and three emergent macrophytes-Arundo donax L., Cyperus alternifolius L. and Typha latifolia L.-alone, were assessed. The aim o…
Kinetic parameter determination in monoculture and monosubstrate biological reactors
1982
The kinetic parameters of a biological reactor, operating under monoculture and monosubstrate conditions, have been determined. Pure cultures of Nocardia corallina and Pseudomonas fluorescens species have been used with phenol as the only organic carbon source. The experimental runs have been carried out both in a batch and in a continuous stirred reactor. The batch results have been interpreted by zero order kinetics in phenol and first order kinetics in biomass. The kinetic-constants have also been calculated. The activation energy has been determined only for the Nocardia species. Using this strain, the continuous reactor, working without biomass recycle, has confirmed the first order ki…
Ethnographic context and spatial coherence of climate indicators for farming communities : a multi-regional comparative assessment
2015
Accurate seasonal predictions of rainfall may reduce climatic risks that farmers are usually faced with across the tropical and subtropical zones. However, although regional-scale seasonal amounts have regularly been forecasted since 1997/98, the practical use of these seasonal predictions is still limited by myriad factors. This paper synthesizes the main resultsof a multi-disciplinary ethnographic and climatic project (PICREVAT). Its main objective was to seek the climatic information ? beyond the seasonal amounts ? critical for crops, both as an actual constraint to crop yields and as identified by the current and past practices and perceptions of farmers. A second goal was to confront t…
Indicators of agricultural intensity and intensification: a review of the literature
2015
Since the 1960s, research has dealt with agricultural intensification (AI) as a solution to ensure global food security. Recently, sustainable intensification (SI) has increasingly been used to describe those agricultural and farming systems that ensure adequate ecosystem service provision. Studies differ in terms of the application scales and methodologies, thus we aim to summarize the main findings from the literature on how AI and SI are assessed, from the farm to global levels. Our literature review is based on 7865 papers selected from the Web of Science database and analysed using CorText software. A further selection of 105 relevant papers was used for an in-depth full-text analysis …
Nitrate leaching in soil: Tracing the NO3− sources with the help of stable N and O isotopes
2007
Abstract Legumes increase the plant-available N pool in soil, but might also increase NO3− leaching to groundwater. To minimize NO3− leaching, N-release processes and the contribution of legumes to NO3− concentrations in soil must be known. Our objectives were (1) to quantify NO3−-N export to >0.3 m soil depth from three legume monocultures (Medicago x varia Martyn, Onobrychis viciifolia Scop., Lathyrus pratensis L.) and from three bare ground plots. Furthermore, we (2) tested if it is possible to apply a mixing model for NO3− in soil solution based on its dual isotope signals, and (3) estimated the contribution of legume mineralization to NO3− concentrations in soil solution under field co…
Harnessing productivity potential and rehabilitation of degraded sodic lands through Jatropha based intercropping systems
2016
Abstract This paper evaluates an intercropping model with J atropha curcas L. (JCL) as an alternative crop on degraded sodic land in north India. Monoculture of JCL has not proven economically viable in India in view of its poor yield; therefore, intercrops in between JCL plantations were tried to optimize land use efficiency. The results revealed that the planting of JCL at 3 × 3 m spacing with inter-cultivation of sweet basil–matricaria (SB-M) cropping system for four years was more economically viable than planting at 3 × 2 m spacing and the other rotations tested in the study. Improvements in soil properties in terms of soil pH, EC and organic carbon were found with the SB-M cropping sy…
Tree species influences diversity of ground-dwelling insects in afforested fields
2015
Abstract Impaired natural ecosystems, such as agricultural lands, are restored toward original or other target stage. Because the long agricultural history has changed the physical, chemical and biological features of the soil, afforested fields can harbor novel species assemblages and interactions. Our overall aim was to quantify the diversity of ground beetles and ants in early successional afforested fields. In a large scale field experiment, we compared plots that had been afforested 25 years ago by planting monocultures of birch, pine or spruce trees. A total of 4080 carabid individuals representing 41 species, and 131,933 ant individuals representing 15 species were recorded. Both the…