Ashes for organic farming

Nowadays only eight percent of the cultivated field area is used for organic farming. The Ministry of Agriculture and Forestry has published the guidelines for the program of organic farming to diversify the supply and the consumption of organic food. The aim is to increase organically arable land to 20% by the year 2020.The demand of organic fertilizer products is strongly increasing. Interest in forestry by-products (ash, bark, zero fiber, etc.) for use in organic production has recently been exceptionally high. For example, development of pelleted fertilizers with zero fiber, ash and a nitrogen-containing fertilizer material is in progress.The ash fertilizer contains many valuable nutrients in fairly optimal ratios: these include phosphorus, potassium, manganese, magnesium, sulfur, zinc, calcium, boron, cobalt, copper and smaller amounts of other trace elements. Ashes contain phosphorus in large amounts, which is useful in organic production. More important nutrients than phosphorus and potassium are apparently trace elements. Neutralizing value of the ash is quite rapid comparedto many liming materials allowed in organic farming. The price quality ratio of ash as a liming material is also good.The use of clean wood ash is permissible in organic production. Peat and straw ash cannot be used in organic production because of the fact that in the EU peat is not considered a renewable resource. Restrictions include only inputs from outside of the organic farm

Current distribution in Hall bars and breakdown of the quantum Hall effect

A numerical study is made of current distribution in small Hall bars with disorder. It is observed, in particular, that in the Hall-plateau regime the Hall current tends to concentrate near the sample edges while it diminishes on average in the sample interior as a consequence of localization. Also reported is another numerical experiment on a related, but rather independent topic, the breakdown of the quantum Hall effect. It is pointed out that the competition of the Hall field with disorder in the sample interior, an intra-subband process, can account for both the magnitude and magnetic-field dependence (proportional to B^{3/2}) of the critical breakdown fields observed experimentally.Comment: 6 pages, Revtex, 3 figures, ep2ds-1

Mesoscopic transport beyond linear response

We present an approach to steady-state mesoscopic transport based on the maximum entropy principle formulation of nonequilibrium statistical mechanics. Our approach is not limited to the linear response regime. We show that this approach yields the quantization observed in the integer quantum Hall effect at large currents, which until now has been unexplained. We also predict new behaviors of non-local resistances at large currents in the presence of dirty contacts.Comment: 14 pages plus one figure (with an insert) (post-script codes appended), RevTeX 3.0, UCF-CM-93-004 (Revised

Microbiology of Bartholin's Duct Abscess

Objective: The aim of the study was to determine the currently most frequent microbial findings in Bartholin's duct abscess

Composite fermion state of spin-orbit coupled bosons

We consider spinor Bose gas with the isotropic Rashba spin-orbit coupling in 2D. We argue that at low density its groundstate is a composite fermion state with a Chern-Simons gauge field and filling factor one. The chemical potential of such a state scales with the density as \mu \propto n^{3/2}. This is a lower energy per particle than \mu \propto n for the earlier suggested groundstate candidates: a condensate with broken time-reversal symmetry and a spin density wave state.Comment: 15 pages, 7 figures, Revte

Estimación de biomasa aérea en pasturas templadas de sistemas lecheros pastoriles

En sistemas lecheros pastoriles la estacionalidad y la variación interanual de la productividad forrajera constituyen la principal restricción tanto biofísica como económica. La medición de biomasa aérea permite estimar el forraje disponible y la productividad forrajera. Para medir la biomasa aérea de un recurso el productor puede utilizar tanto métodos directos como indirectos. El presente trabajo estudia estos métodos de estimación de biomasa aérea en una pastura mixta (trébol blanco, trébol rojo y cebadilla) de un establecimiento lechero ubicado en Suipacha, Pcia. de Buenos Aires (Argentina). Entre 2007 y 2008 tres observadores recorrieron un potrero cada tres semanas y estimaron la biomasa aérea presente en 12 unidades de muestreo de 0,09 m². Luego, se cortó al ras del suelo el material presente en cada unidad, se recolectó y se llevó al laboratorio para su procesamiento. Los métodos indirectos utilizados fueron la estimación visual, el pasturómetro y la regla graduada. Se generaron ecuaciones de calibración para cada método a distintas escalas temporales (Capítulo 2). Los resultados sugieren que los métodos indirectos son buenos estimadores de la biomasa aérea obtenida por cortes, tanto a escala anual como a escala estacional. En algunos casos, la precisión de la calibración del método estuvo afectada por la estación considerada. La validación de los modelos se realizó a dos niveles de análisis (Capítulo 3). La validación con una ecuación por estación sugiere que el método más preciso fue la estimación visual. En cambio, la validación con una ecuación para todo el período sugiere que todos los métodos fueron poco precisos. Algunos de los métodos estudiados en este trabajo, como la estimación visual y el pasturómetro, se presentan como promisorios. El uso de métodos sencillos, económicos y prácticos como estos permitiría mejorar el manejo y la eficiencia de los sistemas de producción de leche de base pastoril

Fertilizer value of urine in pumpkin (Cucurbita maxima L.)cultivation

The fertilizer value of human urine was compared with mineral fertilizer in pumpkin (Cucurbita maxima) cultivation at a dose of 113 kg N ha-1 with no-fertilization used as control. The growth of the vine was better in urine fertilized pumpkins than in mineral fertilized and non-fertilized pumpkins. Total fruit biomass was higher in mineral fertilized plants compared to urine fertilized and non-fertilized pumpkins. Urine fertilized pumpkins may have suffered from lower potassium or higher chloride, thus they produced fewer flowers and fruits. However, total fruit biomass and the number of fruits were slightly higher in urine fertilized plants than in their non-fertilized counterparts, i.e. 17.2 t ha-1 more pumpkin could be produced with urine fertilizer. The microbial hygiene quality as well as the contents of soluble sugars, protein and taste quality were similar in all treatments, but lower nitrate and higher chloride contents were recorded in urine fertilized pumpkins than other treatments. In conclusion, our study shows that the production rate of urine fertilized pumpkins was somewhat lower than mineral fertilized pumpkins but it was higher than non-fertilized pumpkins. The hygienic quality was equally good with all treatments