The effect of nitrogen fertilization on root characteristics of Camelina sativa L. in greenhouse pots

Climate change has made mandatory the introduction of new crops in Greece, such as the cultivation of camelina [Camelina sativa (L.) Crantz]. Nitrogen (N) and the development of root system are two important factors affecting crop growth and yield. Camelina has been studied mainly for its composition and oil. In the present study, root development of camelina crop was thoroughly investigated; mainly in terms of Nitrogen fertilization. Therefore, a camelina greenhouse experiment was established in Western Greece, in the region of Agrinio, in March 2019 in completely randomized design with four treatments, (control 0 ppm N, 30 ppm N, 60, ppm N and 90 ppm N). The N rates had statistically significant affected root density and root surface from 40 to 120 days after treatment (DAT) with highest values at 100 DAT and 90 ppm N, 52.54 cm of root 100 cm-3 and 27.59 cm2 of root 100 cm-3 , respectively. The root volume was significantly affected by N fertilizer from 40 to 100 DAT and highest value was 13.18 cm3 of root 100 cm-3 soil in the 90 ppm at 120 DAT. The plant leaf area was significantly affected by the highest rate of N. Yield per plant had not statistically significant difference with the 60 and with the 90 and highest weight per plant 292.25 g plant-1 in 90 ppm. In conclusion, Ν fertilization significantly affected growth or camelina’s root system after 40 DAT. Plant growth was significantly affected by fertilization and the highest yield and 1,000 seed weight were recorded with the highest amount of N

Teff (Eragrostis tef (Zucc.) Trotter) fodder yield and quality as affected by cutting frequency

Teff (Eragrostis tef (Zucc.) Trotter) is a well-adapted, fast-growing crop with competitive forage quality as its nutritive value for livestock fodder is similar to other grasses utilized as hay or ensiled feeds. Two field experiments were conducted from May to October 2017 in order to determine the effect of cutting frequency on yield and quality of teff (Eragrostis tef) as fodder crop under Mediterranean climatic conditions. The agronomic performance and nutritive value of teff was analyzed in order to define alternatives to local forages for animal feeding in the Mediterranean region. The experiments conducted at two sites (Western and Central Greece) were laid out in a completely randomized design with three replicates and three cutting frequencies (10, 20, 30 days’ interval between cuttings - F10, F20, and F30, respectively). The results of this study demonstrate that the cutting interval has a marked effect on the fodder yield and quality. The highest total dry matter yield (6,322–6,778 kg ha-1) was found in F10 treatment. In terms of qualitative characteristics, the highest fat levels and lowest ADF levels was found in F30 treatment, the highest protein levels and the lowest NDF levels in F10 treatment, and the highest levels of fibrous substances, ADF and NDF, in F20 treatment. Data suggest that teff could be successfully integrated into Mediterannean grasslands with the prospect for improving their nutritional quality and the possibility for increasing protein yield through the application of frequent cuttings

Poincaré on the Foundation of Geometry in the Understanding

This paper is about Poincaré’s view of the foundations of geometry. According to the established view, which has been inherited from the logical positivists, Poincaré, like Hilbert, held that axioms in geometry are schemata that provide implicit definitions of geometric terms, a view he expresses by stating that the axioms of geometry are “definitions in disguise.” I argue that this view does not accord well with Poincaré’s core commitment in the philosophy of geometry: the view that geometry is the study of groups of operations. In place of the established view I offer a revised view, according to which Poincaré held that axioms in geometry are in fact assertions about invariants of groups. Groups, as forms of the understanding, are prior in conception to the objects of geometry and afford the proper definition of those objects, according to Poincaré. Poincaré’s view therefore contrasts sharply with Kant’s foundation of geometry in a unique form of sensibility. According to my interpretation, axioms are not definitions in disguise because they themselves implicitly define their terms, but rather because they disguise the definitions which imply them

Effects of nitrogen fertilizers with two different inhibitors (urease and nitrification) on the survival and activity of earthworms (Octodrilus complanatus)

Earthworms are among the most important species of the soil macrofauna. However, they are very sensitive to inorganic fertilization, more specifically to urea, which makes them a well-known bio-indicator. The objective of this study was to test if a fertilizer with inhibitors could be less destructive to earthworms than urea. In two consecutive years, we studied how new type fertilizers with urea (urea + urease inhibitor, urea + nitrification inhibitor and urea + urease inhibitor + nitrification inhibitor) can differ from urea applied alone and be closer to control (no fertilizer) in terms of the impact on earthworms, verified on different days after application. The measurements concerned earthworms’ mortality, casts and weight. Moreover, some soil properties which are affected by earthworms’ activity, such as exchangeable Ca, cation exchange capacity (CEC) and soil CO2 respiration, were studied. The inhibitors that were used comprised nitrification inhibitor, dicyandiamide (DCD), urease inhibitor, N-(n-butyl) thiophosphoric triamide (NBPT), and double inhibitors, both urease and nitrification inhibitor. The study revealed how a fertilizer with inhibitors could be less destructive to earthworms than urea. Urea with urease inhibitor and urea with urease inhibitor and nitrification inhibitor had the least negative impact on earthworms’ activities. In contrast, urea and urea with nitrification inhibitor caused higher mortality among earthworms than the other fertilizers used

Effects of organic and inorganic fertilization on growth and yield of Physalis peruviana L. crop under Mediterranean conditions

Physalis peruviana L. is an Andean Solanaceae fruit crop with great nutraceutical qualities, potential health benefits and adaptability to Mediterranean climates. In the current study, a first approach on the effect of organic and inorganic fertilization on P. peruviana crop under Mediterranean semi-arid conditions was performed. A field experiment was laid out according to a completely randomized design, with three replicates and three fertilization treatments [untreated (control), organic fertilization (biocyclic humus soil) and inorganic fertilization (inorganic fertilizer 40-0-0+14.5 SO3)]. Phenological growth stages and their corresponded growing degree days were evaluated. In addition, some growth parameters, fruit yield and yield components were evaluated. The results indicated that the duration of phenological growth stages was in accordance with durations mentioned in tropical climate. The highest branches number per plant (24.4), leaf area per plant (1997.3 cm2), fruit number per plant (41.52), fruit yield (7.51 t ha-1) and average fruit weight (5.32 g) were found in inorganic fertilization plots, whereas the highest plant height (44.15 g) and fruit diameter (12.52 mm) were recorded under organic fertilization; however, the differences between the organic and inorganic fertilization were not statistically significant. In terms of dry weight per plant, there were significant differences among the fertilization treatment with the values obtained under inorganic fertilization (81.24 g). To sum up, P. peruviana showed satisfying adaptability under Mediterranean climate conditions and has great potential in becoming an alternative cultivation for small and medium producers of Mediterranean countries. In addition, the results indicated that organic fertilization (with biocyclic humus soil) should be considered as an alternative to inorganic fertilizers for P. peruviana production. © Articles by the authors; SHST, Cluj-Npoc, Romania

Church-Turing Thesis, in Practice

We aim at providing a philosophical analysis of the notion of “proof by Church’s Thesis”, which is – in a nutshell – the conceptual device that permits to rely on informal methods when working in Computability Theory. This notion allows, in most cases, to not specify the background model of computation in which a given algorithm – or a construction – is framed. In pursuing such analysis, we carefully reconstruct the development of this notion (from Post to Rogers, to the present days), and we focus on some classical constructions of the field, such as the construction of a simple set. Then, we make use of this focus in order to support the following encompassing claim (which opposes to a somehow commonly received view): the informal side of Computability, consisting of the large class of methods typically employed in the proofs of the field, is not fully reducible to its formal counterpart