1,721,153 research outputs found
Yields and Yield Stability of Continuous Corn Under Different Agronomic Management Systems.
No full textIn Central Italy corn (Zea mays L.) is often cultivated in continuous cropping, i.e., the same crop is cultivated over the years on the same fields. In these simplified cropping systems, high inputs are generally required to maintain adequate yields, but environmental and economic concerns have spurred researchers to explore different solutions. Alternative cropping systems requires a systemic dimension to boost helpful interactions among all the parts of farming systems. However, differing managements trigger cropping systems to change gradually over time so that short-term experiments cannot lead to accurate conclusions on how to design and manage sustainable cropping systems that can sustain themselves over the long period, in an economically environmentally and socially fair way. To fill this gap, corn grain yield has been studied for ten years (2011-2020) in a Mediterranean area in a long-term field experiment comparing three cropping systems in a randomized block design with three replicates, on plots of real size allowing usual farm machinery. The suite of agronomically coherent practices imposed in each treatment denoted different agronomic rationales: high-input (HI referring to local standard techniques to maximize yield and economic profitability by conventional tillage, and great use of mineral fertilization and herbicides; low-input (LI) following a low input strategy with minimum tillage, and reduced application of pesticides and fertilizers; conservative (CT) adopting conservation practices to reduce costs and energy consumption with tillage, sowing, mineral fertilization, and chemical weed control executed in cultivated strips.
The agronomical, economic, and environmental performances of the cropping systems were assessed. Main results on yield and yield stability across 10 years of field experiments indicated that that yields were positively correlated to the level of adopted inputs, but environmental conditions may affect the cropping system performances. Our analysis seemed suitable to identify production trends and provide information about temporal yield stability
L'evoluzione della flora infestante in differenti sistemi colturali. Nota II. Effetti sulla struttura delle comunità di malerbe.
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L'evoluzione della flora infestante in differenti sistemi colturali. Nota I. Effetti sulla densità delle malerbe.
No full textAssessing specific vulnerability of shallow aquifers to pesticide using GIS tools. data needs and reliability of index-overlay methods: An application to the san giuliano terme agricultural area (Pisa, Italy)
Full text linkPesticides play a crucial role in regulating crop production by reducing crop losses and increasing crop yield and quality. However, they may threaten surface and groundwater, a phenomenon occurring at global scale, potentially causing environmental damage and prohibition of water use or high treatment costs for drinking water. Assessing spatially-defined aquifer vulnerability to pesticide is then important, as it may allow defining agricultural areas where pesticides should be used following well-defined agronomic practices/limitations. In this study, after a brief review of recent studies on aquifer vulnerability assessment to pesticide, we applied the Vulnerability Index method to the agricultural area of the Municipality of San Giuliano Terme (Pisa, Italy) in order to focus on the data needs and discuss the reliability of this method (as an example of index-overlay methods). The proposed method needs a relatively small number of parameters compared to other more complex ones. Despite a such a small number of parameters, some were not easily available in our case study. Thus, some assumptions were made. This led to vulnerability maps with reduced reliability, no validation with groundwater samples, and little practical use. This means that to produce robust but static vulnerability assessments, large datasets are needed. In turn, the cost of data gathering may be high. The value of these data may, however, be increased, and the cost better justified if the analyses are based on process-based or advanced statistical methods. While the future for vulnerability assessment methods is the use of process-based/advanced statistical methods, index-overlay methods, as a preliminary step for process-based simulation analysis, may still provide initial and relatively quick insights on potential leaching of pesticides. This in turn may support extension services in delivering timely and relevant advices on the use of such pesticides to farmers and owners of plant nurseries and greenhouses
Un’agricoltura per le aree protette.
No full textL’agricoltura costituisce da sempre parte integrante dell’ambiente e del paesaggio e contribuisce significativamente a modularne conformazione e caratteristiche. Lo studio dell’interazione fra i sistemi agricoli ed il territorio è il presupposto per la definizione e la realizzazione di soluzioni integrate che consentano di razionalizzare i processi produttivi a salvaguardia delle risorse naturali.
Questi concetti diventano ancora più importanti all’interno delle aree protette, dove l'agricoltura deve sapere rispondere alle peculiari esigenze di conservazione e valorizzazione delle risorse ambientali.
Il libro presenta i risultati del progetto di ricerca MIUR-PRIN 2004 “Un’agricoltura per le aree protette” i cui contenuti riguardano:
➢ l'analisi di metodologie di lavoro per valutare la compatibilità ambientale ed economica delle attività agricole all’interno delle aree protette;
➢ l'applicazione di tali metodologie in una serie di realtà italiane di elevato valore ambientale;
➢ l'individuazione di punti di forza e di sofferenza nei rapporti agricoltura/ambiente nelle aree studio;
➢ la valutazione di possibili strategie di mitigazione degli impatti o di esaltazione del ruolo virtuoso dell’agricoltura per giungere alla definizione di codici locali di buona pratica agricola;
➢ lo sviluppo di metodi partecipativi per l’applicazione degli itinerari tecnici eco-compatibili.
Il progetto ha coinvolto sei unità di ricerca italiane, operanti in realtà agro-ambientali nettamente diverse (parchi fluviali, lacuo-palustri e peri urbani di pianura nel centro nord Italia, nonché zone protette collinari al nord, al centro e nel meridione) che offrono uno spaccato alquanto composito su problematiche e contributi dell’agricoltura nella gestione dei territori protetti
Intercropping cover crops with a poplar short rotation coppice: effects on nutrient uptake and biomass production
No full textThe risks of soil erosion and nutrient leaching can be considered appreciable in short rotation coppices especially in the first growth phases because of the absence of any plant cover. The temporary intercropping with legumes or grasses used as cover crops can help to overcome these environmental issues. The present research work aims to evaluate the effects of the introduction of cover crops in a short rotation poplar (Populus deltoides W. Bartram ex Marshall) with two-year harvest cycle. The plantation was located in a Typic Xerofluvent, silty-loam soil of the coastal Central Italy. Two different species of cover crops, Trilblium subterraneum L. (TS) and Lolitnn perenne L. (LP), were compared along with an untreated control, colonised by spontaneous vegetation WO). Several plant and soil parameters Were evaluated: the above ground biomass and nutrient accumulation for the three different soil cover types, the nitrate and water content in two soil layers (0.00-0.30 and 0.30-0.60 m), the poplar yield and nutrient content in branches and leaves. TS returned to the soil about 7(1 kg ha-1 of nitrogen at the end of its biological cycle, thanks to the high N content (over 20) and to the noticeable amount of dry matter produced (3.46 t ha I of dry matter). This value was considerably higher than those of the LP (23 kg ha-1 of N) or CO (10 kg ha-1). The different amotutt of nitrogen returned to the soil affected both nitrate concen topsoil (0.00-0.30 in) and accumulation ge organs. Concerning phosphorous, the differences amvng treatments were less evident and the amount of P returned to the soil ranged from 2 (CO) to 10 (TS) kg ha 1. However, the effect of soil cover type on P uptake in poplar was still appreciable. Generally, the soil water content was ly affected by the types. Indeed, the differences between the cover crops and the control became significant only in the shallowest soil layer and over the summer season. In the first year, LP induced a significant decrease in poplar yield (10.1 t ha I of dry matter) in comparison with TS (14.7 t ha-1) and CO (13.4 t ha-1), whereas in the second year there were no significant differences among treatments due to the weak regrowth of cover crops. These results show how dke it feasible a long lasting coexistence between cover crops and SRC, a clever design of agro-forestry systems is therefore needed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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