Topological invariance and spatial scaling of surface roughness in two highly eroded zones of Mexico: a comparative study

The Fractal Image Informatics toolbox (Oleschko et al., 2008 a; Torres-Arg��elles et al., 2010) was applied to extract, classify and model the topological structure and dynamics of surface roughness in two highly eroded catchments of Mexico. Both areas are affected by gully erosion (Sidorchuk, 2005) and characterized by avalanche-like matter transport. Five contrasting morphological patterns were distinguished across the slope of the bare eroded surface of Faeozem (Queretaro State) while only one (apparently independent on the slope) roughness pattern was documented for Andosol (Michoacan State). We called these patterns ?the roughness clusters? and compared them in terms of metrizability, continuity, compactness, topological connectedness (global and local) and invariance, separability, and degree of ramification (Weyl, 1937). All mentioned topological measurands were correlated with the variance, skewness and kurtosis of the gray-level distribution of digital images. The morphology0 spatial dynamics of roughness clusters was measured and mapped with high precision in terms of fractal descriptors. The Hurst exponent was especially suitable to distinguish between the structure of ?turtle shell? and ?ramification? patterns (sediment producing zone A of the slope); as well as ?honeycomb? (sediment transport zone B) and ?dinosaur steps? and ?corals? (sediment deposition zone C) roughness clusters. Some other structural attributes of studied patterns were also statistically different and correlated with the variance, skewness and kurtosis of gray distribution of multiscale digital images. The scale invariance of classified roughness patterns was documented inside the range of five image resolutions. We conjectured that the geometrization of erosion patterns in terms of roughness clustering might benefit the most semi-quantitative models developed for erosion and sediment yield assessments (de Vente and Poesen, 2005).

Numerical characterization of particle dispersion in the turbulent recirculation zones of sudden expansion pipe flows

The dispersion of solid particles in the turbulent recirculation zones of sudden expansion pipes can be characterized by different Stokes numbers and mean drift parameter and its study is important because this kind of flows appears in many technological applications.

Advanced system of planning and organization of classes at the university

This document is the result of a process of web development to create a tool that will allow to Cracow University of Technology consult, create and manage timetables. The technologies chosen for this purpose are Apache Tomcat Server, My SQL Community Server, JDBC driver, Java Servlets and JSPs for the server side. The client part counts on Javascript, jQuery, AJAX and CSS technologies to perform the dynamism. The document will justify the choice of these technologies and will explain some development tools that help in the integration and development of all this elements: specifically, NetBeans IDE and MySQL workbench have been used as helpful tools. After explaining all the elements involved in the development of the web application, the architecture and the code developed are explained through UML diagrams. Some implementation details related to security are also deeper explained through sequence diagrams. As the source code of the application is provided, an installation manual has been developed to run the project. In addition, as the platform is intended to be a beta that will be grown, some unimplemented ideas for future development are also exposed. Finally, some annexes with important files and scripts related to the initiation of the platform are attached. This project started through an existing tool that needed to be expanded. The main purpose of the project along its development has focused on setting the roots for a whole new platform that will replace the existing one. For this goal, it has been needed to make a deep inspection on the existing web technologies: a web server and a SQL database had to be chosen. Although the alternatives were a lot, Java technology for the server was finally selected because of the big community backwards, the easiness of modelling the language through UML diagrams and the fact of being free license software. Apache Tomcat is the open source server that can use Java Servlet and JSP technology. Related to the SQL database, MySQL Community Server is the most popular open-source SQL Server, with a big community after and quite a lot of tools to manage the server. JDBC is the driver needed to put in contact Java and MySQL. Once we chose the technologies that would be part of the platform, the development process started. After a detailed explanation of the development environment installation, we used UML use case diagrams to set the main tasks of the platform; UML class diagrams served to establish the existing relations between the classes generated; the architecture of the platform was represented through UML deployment diagrams; and Enhanced entity���relationship (EER) model were used to define the tables of the database and their relationships. Apart from the previous diagrams, some implementation issues were explained to make a better understanding of the developed code - UML sequence diagrams helped to explain this. Once the whole platform was properly defined and developed, the performance of the application has been shown: it has been proved that with the current state of the code, the platform covers the use cases that were set as the main target. Nevertheless, some requisites needed for the proper working of the platform have been specified. As the project is aimed to be grown, some ideas that could not be added to this beta have been explained in order not to be missed for future development. Finally, some annexes containing important configuration issues for the platform have been added after proper explanation, as well as an installation guide that will let a new developer get the project ready. In addition to this document some other files related to the project are provided: - Javadoc. The Javadoc containing the information of every Java class created is necessary for a better understanding of the source code. - database_model.mwb. This file contains the model of the database for MySQL Workbench. This model allows, among other things, generate the MySQL script for the creation of the tables. - ScheduleManager.war. The WAR file that will allow loading the developed application into Tomcat Server without using NetBeans. - ScheduleManager.zip. The source code exported from NetBeans project containing all Java packages, JSPs, Javascript files and CSS files that are part of the platform. - config.properties. The configuration file to properly get the names and credentials to use the database, also explained in Annex II. Example of config.properties file. - db_init_script.sql. The SQL query to initiate the database explained in Annex III. SQL statements for MySQL initialization. RESUMEN. Este proyecto tiene como punto de partida la necesidad de evoluci��n de una herramienta web existente. El prop��sito principal del proyecto durante su desarrollo se ha centrado en establecer las bases de una completamente nueva plataforma que reemplazar�� a la existente. Para lograr esto, ha sido necesario realizar una profunda inspecci��n en las tecnolog��as web existentes: un servidor web y una base de datos SQL deb��an ser elegidos. Aunque existen muchas alternativas, la tecnolog��a Java ha resultado ser elegida debido a la gran comunidad de desarrolladores que tiene detr��s, adem��s de la facilidad que proporciona este lenguaje a la hora de modelarlo usando diagramas UML. Tampoco hay que olvidar que es una tecnolog��a de uso libre de licencia. Apache Tomcat es el servidor de c��digo libre que permite emplear Java Servlets y JSPs para hacer uso de la tecnolog��a de Java. Respecto a la base de datos SQL, el servidor m��s popular de c��digo libre es MySQL, y cuenta tambi��n con una gran comunidad detr��s y buenas herramientas de modelado, creaci��n y gesti��n de la bases de datos. JDBC es el driver que va a permitir comunicar las aplicaciones Java con MySQL. Tras elegir las tecnolog��as que formar��an parte de esta nueva plataforma, el proceso de desarrollo tiene comienzo. Tras una extensa explicaci��n de la instalaci��n del entorno de desarrollo, se han usado diagramas de caso de UML para establecer cu��les son los objetivos principales de la plataforma; los diagramas de clases nos permiten realizar una organizaci��n del c��digo java desarrollado de modo que sean f��cilmente entendibles las relaciones entre las diferentes clases. La arquitectura de la plataforma queda definida a trav��s de diagramas de despliegue. Por ��ltimo, diagramas EER van a definir las relaciones entre las tablas creadas en la base de datos. Aparte de estos diagramas, algunos detalles de implementaci��n se van a justificar para tener una mejor comprensi��n del c��digo desarrollado. Diagramas de secuencia ayudar��n en estas explicaciones. Una vez que toda la plataforma haya quedad debidamente definida y desarrollada, se va a realizar una demostraci��n de la misma: se demostrar�� c��mo los objetivos generales han sido alcanzados con el desarrollo actual del proyecto. No obstante, algunos requisitos han sido aclarados para que la plataforma trabaje adecuadamente. Como la intenci��n del proyecto es crecer (no es una versi��n final), algunas ideas que se han podido llevar acabo han quedado descritas de manera que no se pierdan. Por ��ltimo, algunos anexos que contienen informaci��n importante acerca de la plataforma se han a��adido tras la correspondiente explicaci��n de su utilidad, as�� como una gu��a de instalaci��n que va a permitir a un nuevo desarrollador tener el proyecto preparado. Junto a este documento, ficheros conteniendo el proyecto desarrollado quedan adjuntos. Estos ficheros son: - Documentaci��n Javadoc. Contiene la informaci��n de las clases Java que han sido creadas. - database_model.mwb. Este fichero contiene el modelo de la base de datos para MySQL Workbench. Esto permite, entre otras cosas, generar el script de iniciaci��n de la base de datos para la creaci��n de las tablas. - ScheduleManager.war. El fichero WAR que permite desplegar la plataforma en un servidor Apache Tomcat. - ScheduleManager.zip. El c��digo fuente exportado directamente del proyecto de Netbeans. Contiene todos los paquetes de Java generados, ficheros JSPs, Javascript y CSS que forman parte de la plataforma. - config.properties. Ejemplo del fichero de configuraci��n que permite obtener los nombres de la base de datos - db_init_script.sql. Las consultas SQL necesarias para la creaci��n de la base de datos.

Efficiency and environmental indexes to evaluate the sustainability of mineral and organic fertilization in an irrigated melon crop

Melon is traditionally cultivated in fertigated farmlands in the center of Spain with high inputs of water and N fertilizer. Excess N can have a negative impact, from the economic point of view, since it can diminish the production and quality of the fruit, from the environmental point of view, since it is a very mobile element in the soil and can contaminate groundwater. From health point of view, nitrate can be accumulated in fruit pulp, and, in addition, groundwater is the fundamental supply source of human populations. Best management practices are particularly necessary in this region as many zones have been declared vulnerable to NO3- pollution (Directive 91/676/CEE) During successive years, a melon crop (Cucumis melo L.) was grown under field conditions applying mineral and organic fertilizers under drip irrigation. Different doses of ammonium nitrate were used as well as compost derived from the wine-distillery industry which is relevant in this area. The present study reviews the most common N efficiency indexes under the different management options with a view to maximizing yield and minimizing N loss.

Agricultural use of organic wastes as source of nitrogen and phosphorus: risks and opportunities

El nitr��geno (N) y el f��sforo (P) son nutrientes esenciales en la producci��n de cultivos. El desarrollo de los fertilizantes de s��ntesis durante el siglo XX permiti�� una intensificaci��n de la agricultura y un aumento de las producciones pero a su vez el gran input de nutrientes ha resultado en algunos casos en sistemas poco eficientes incrementando las p��rdidas de estos nutrientes al medio ambiente. En el caso del P, este problema se agrava debido a la escasez de reservas de roca fosf��rica necesaria para la fabricaci��n de fertilizantes fosfatados. La utilizaci��n de residuos org��nicos en agricultura como fuente de N y P es una buena opci��n de manejo que permite valorizar la gran cantidad de residuos que se generan. Sin embargo, es importante conocer los procesos que se producen en el suelo tras la aplicaci��n de los mismos, ya que influyen en la disponibilidad de nutrientes que pueden ser utilizados por el cultivo as�� como en las p��rdidas de nutrientes de los agrosistemas que pueden ocasionar problemas de contaminaci��n. Aunque la din��mica del N en el suelo ha sido m��s estudiada que la del P, los problemas importantes de contaminaci��n por nitratos en zonas vulnerables hacen necesaria la evaluaci��n de aquellas pr��cticas de manejo que pudieran agravar esta situaci��n, y en el caso de los residuos org��nicos, la evaluaci��n de la respuesta agron��mica y medioambiental de la aplicaci��n de materiales con un alto contenido en N (como los residuos procedentes de la industria vin��cola y alcoholera). En cuanto al P, debido a la mayor complejidad de su ciclo y de las reacciones que ocurren en el suelo, hay un mayor desconocimiento de los factores que influyen en su din��mica en los sistemas suelo-planta, lo que supone nuevas oportunidades de estudio en la evaluaci��n del uso agr��cola de los residuos org��nicos. Teniendo en cuenta los conocimientos previos sobre cada nutriente as�� como las necesidades espec��ficas en el estudio de los mismos, en esta Tesis se han evaluado: (1) el efecto de la aplicaci��n de residuos procedentes de la industria vin��cola y alcoholera en la din��mica del N desde el punto de vista agron��mico y medioambiental en una zona vulnerable a la contaminaci��n por nitratos; y (2) los factores que influyen en la disponibilidad de P en el suelo tras la aplicaci��n de residuos org��nicos. Para ello se han llevado a cabo incubaciones de laboratorio as�� como ensayos de campo que permitieran evaluar la din��mica de estos nutrientes en condiciones reales. Las incubaciones de suelo en condiciones controladas de humedad y temperatura para determinar el N mineralizado se utilizan habitualmente para estimar la disponibilidad de N para el cultivo as�� como el riesgo medioambiental. Por ello se llev�� a cabo una incubaci��n en laboratorio para conocer la velocidad de mineralizaci��n de N de un compost obtenido a partir de residuos de la industria vin��cola y alcoholera, ampliamente distribuida en Castilla-La Mancha, regi��n con problemas importantes de contaminaci��n de acu��feros por nitratos. Se probaron tres dosis crecientes de compost correspondientes a 230, 460 y 690 kg de N total por hect��rea que se mezclaron con un suelo franco arcillo arenoso de la zona. La evoluci��n del N mineral en el suelo a lo largo del tiempo se ajust�� a un modelo de regresi��n no lineal, obteniendo valores bajos de N potencialmente mineralizable y bajas contantes de mineralizaci��n, lo que indica que se trata de un material resistente a la mineralizaci��n y con una lenta liberaci��n de N en el suelo, mineraliz��ndose tan solo 1.61, 1.33 y 1.21% del N total aplicado con cada dosis creciente de compost (para un periodo de seis meses). Por otra parte, la mineralizaci��n de N tras la aplicaci��n de este material tambi��n se evalu�� en condiciones de campo, mediante la elaboraci��n de un balance de N durante dos ciclos de cultivo (2011 y 2012) de mel��n bajo riego por goteo, cultivo y manejo agr��cola muy caracter��sticos de la zona de estudio. Las constantes de mineralizaci��n obtenidas en el laboratorio se ajustaron a las temperaturas reales en campo para predecir el N mineralizado en campo durante el ciclo de cultivo del mel��n, sin embargo este modelo generalmente sobreestimaba el N mineralizado observado en campo, por la influencia de otros factores no tenidos en cuenta para obtener esta predicci��n, como el N acumulado en el suelo, el efecto de la planta o las fluctuaciones de temperatura y humedad. Tanto el ajuste de los datos del laboratorio al modelo de mineralizaci��n como las predicciones del mismo fueron mejores cuando se consideraba el efecto de la mezcla suelo-compost que cuando se aislaba el N mineralizado del compost, mostrando la importancia del efecto del suelo en la mineralizaci��n del N procedente de residuos org��nicos. Dado que esta zona de estudio ha sido declarada vulnerable a la contaminaci��n por nitratos y cuenta con diferentes unidades hidrol��gicas protegidas, en el mismo ensayo de campo con mel��n bajo riego por goteo se evalu�� el riesgo de contaminaci��n por nitratos tras la aplicaci��n de diferentes dosis de compost bajo dos reg��menes de riego, riego ajustado a las necesidades del cultivo (90 �� 100% de la evapotranspiraci��n del cultivo (ETc)) o riego excedentario (120% ETc). A lo largo del ciclo de cultivo se estim�� semanalmente el drenaje mediante la realizaci��n de un balance h��drico, as�� como se tomaron muestras de la soluci��n de suelo y se determin�� su concentraci��n de nitratos. Para evaluar el riesgo de contaminaci��n de las aguas subterr��neas asociado con estas pr��cticas, se utilizaron algunos ��ndices medioambientales para determinar la variaci��n en la calidad del agua potable (��ndice de Impacto (II)) y en la concentraci��n de nitratos del acu��fero (��ndice de Impacto Ambiental (EII)). Para combinar par��metros medioambientales con par��metros de producci��n, se calcul�� la eficiencia de manejo. Se observ�� que la aplicaci��n de compost bajo un r��gimen de riego ajustado no aumentaba el riesgo de contaminaci��n de las aguas subterr��neas incluso con la aplicaci��n de la dosis m��s alta. Sin embargo, la aplicaci��n de grandes cantidades de compost combinada con un riego excedentario supuso un incremento en el N lixiviado a lo largo del ciclo de cultivo, mientras que no se obtuvieron mayores producciones con respecto al riego ajustado. La aplicaci��n de residuos de la industria vin��cola y alcoholera como fuente de P fue evaluada en suelos calizos caracterizados por una alta capacidad de retenci��n de P, lo cual en algunos casos limita la disponibilidad de este nutriente. Para ello se llev�� a cabo otro ensayo de incubaci��n con dos suelos de diferente textura, con diferente contenido de carbonato c��lcico, hierro y con dos niveles de P disponible; a los que se aplicaron diferentes materiales procedentes de estas industrias (con y sin compostaje previo) aportando diferentes cantidades de P. A lo largo del tiempo se analiz�� el P disponible del suelo (P Olsen) as�� como el pH y el carbono org��nico disuelto. Al final de la incubaci��n, con el fin de estudiar los cambios producidos por los diferentes residuos en el estado del P del suelo se llev�� a cabo un fraccionamiento del P inorg��nico del suelo, el cual se separ�� en P soluble y d��bilmente enlazado (NaOH-NaCl-P), P soluble en reductores u ocluido en los ��xidos de Fe (CBD-P) y P poco soluble precipitado como Ca-P (HCl-P); y se determin�� la capacidad de retenci��n de P as�� como el grado de saturaci��n de este elemento en el suelo. En este ensayo se observ�� que, dada la naturaleza caliza de los suelos, la influencia de la cantidad de P aplicado con los residuos en el P disponible s��lo se produc��a al comienzo del periodo de incubaci��n, mientras que al final del ensayo el incremento en el P disponible del suelo se igualaba independientemente del P aplicado con cada residuo, aumentando el P retenido en la fracci��n menos soluble con el aumento del P aplicado. Por el contrario, la aplicaci��n de materiales org��nicos menos estabilizados y con un menor contenido en P, produjo un aumento en las formas de P m��s l��biles debido a una disoluci��n del P retenido en la fracci��n menos l��bil, lo cual demostr�� la influencia de la materia org��nica en los procesos que controlan el P disponible en el suelo. La aplicaci��n de residuos aument�� el grado de saturaci��n de P de los suelos, sin embargo los valores obtenidos no superaron los l��mites establecidos que indican un riesgo de contaminaci��n de las aguas. La influencia de la aplicaci��n de residuos org��nicos en las formas de P inorg��nico y org��nico del suelo se estudi�� adem��s en un suelo ��cido de textura areno francosa tras la aplicaci��n en campo a largo plazo de esti��rcol vacuno y de compost obtenido a partir de biorresiduos, as�� como la aplicaci��n combinada de compost y un fertilizante mineral (superfosfato tripe), en una rotaci��n de cultivos. En muestras de suelo recogidas 14 a��os despu��s del establecimiento del experimento en campo, se determin�� el P soluble y disponible, la capacidad de adsorci��n de P, el grado de saturaci��n de P as�� como diferentes actividades enzim��ticas (actividad deshidrogenasa, fosfatasa ��cida y fosfatasa alcalina). Las diferentes formas de P org��nico en el suelo se estudiaron mediante una t��cnica de adici��n de enzimas con diferentes substratos espec��ficos a extractos de suelo de NaOH-EDTA, midiendo el P hidrolizado durante un periodo de incubaci��n por colorimetr��a. Las enzimas utilizadas fueron la fosfatasa ��cida, la nucleasa y la fitasa las cuales permitieron identificar mono��steres hidrolizables (monoester-like P), di��steres (DNA-like P) e inositol hexaquifosfato (Ins6P-like P). La aplicaci��n a largo plazo de residuos org��nicos aument�� el P disponible del suelo proporcionalmente al P aplicado con cada tipo de fertilizaci��n, suponiendo un mayor riesgo de p��rdidas de P dado el alto grado de saturaci��n de este suelo. La aplicaci��n de residuos org��nicos aument�� el P org��nico del suelo resistente a la hidr��lisis enzim��tica, sin embargo no influy�� en las diferentes formas de P hidrolizable por las enzimas en comparaci��n con las observadas en el suelo sin enmendar. Adem��s, las diferentes formas de P org��nico aplicadas con los residuos org��nicos no se correspondieron con las analizadas en el suelo lo cual demostr�� que ��stas son el resultado de diferentes procesos en el suelo mediados por las plantas, los microorganismos u otros procesos abi��ticos. En este estudio se encontr�� una correlaci��n entre el Ins6P-like P y la actividad microbiana (actividad deshidrogenasa) del suelo, lo cual refuerza esta afirmaci��n. Por ��ltimo, la aplicaci��n de residuos org��nicos como fuente de N y P en la agricultura se evalu�� agron��micamente en un escenario real. Se estableci�� un experimento de campo para evaluar el compost procedente de residuos de bodegas y alcoholeras en el mismo cultivo de mel��n utilizado en el estudio de la mineralizaci��n y lixiviaci��n de N. En este experimento se estudi�� la aplicaci��n de tres dosis de compost: 1, 2 y 3 kg de compost por metro lineal de plantaci��n correspondientes a 7, 13 y 20 t de compost por hect��rea respectivamente; y se estudi�� el efecto sobre el crecimiento de las plantas, la acumulaci��n de N y P en la planta, as�� como la producci��n y calidad del cultivo. La aplicaci��n del compost produjo un ligero incremento en la biomasa vegetal acompa��ado por una mejora significativa de la producci��n con respecto a las parcelas no enmendadas, obteni��ndose la m��xima producci��n con la aplicaci��n de 2 kg de compost por metro lineal. Aunque los efectos potenciales del N y P fueron parcialmente enmascarados por otras entradas de estos nutrientes en el sistema (alta concentraci��n de nitratos en el agua de riego y ��cido fosf��rico suministrado por fertirrigaci��n), se observ�� una mayor acumulaci��n de P uno de los a��os de estudio que result�� en un aumento en el n��mero de frutos en las parcelas enmendadas. Adem��s, la mayor acumulaci��n de N y P disponible en el suelo al final del ciclo de cultivo indic�� el potencial uso de estos materiales como fuente de estos nutrientes. ABSTRACT Nitrogen (N) and phosphorus (P) are essential nutrients in crop production. The development of synthetic fertilizers during the 20th century allowed an intensification of the agriculture increasing crop yields but in turn the great input of nutrients has resulted in some cases in inefficient systems with higher losses to the environment. Regarding P, the scarcity of phosphate rock reserves necessary for the production of phosphate fertilizers aggravates this problem. The use of organic wastes in agriculture as a source of N and P is a good option of management that allows to value the large amount of wastes generated. However, it is important to understand the processes occurring in the soil after application of these materials, as they affect the availability of nutrients that can be used by the crop and the nutrient losses from agricultural systems that can cause problems of contamination. Although soil N dynamic has been more studied than P, the important concern of nitrate pollution in Nitrate Vulnerable Zones requires the evaluation of those management practices that could aggravate this situation, and in the case of organic wastes, the evaluation of the agronomic and environmental response after application of materials with a high N content (such as wastes from winery and distillery industries). On the other hand, due to the complexity of soil P cycle and the reactions that occur in soil, there is less knowledge about the factors that can influence its dynamics in the soil-plant system, which means new opportunities of study regarding the evaluation of the agricultural use of organic wastes. Taking into account the previous knowledge of each nutrient and the specific needs of study, in this Thesis we have evaluated: (1) the effect of the application of wastes from the winery and distillery industries on N dynamics from the agronomic and environmental viewpoint in a vulnerable zone; and (2) the factors that influence P availability in soils after the application of organic wastes. With this purposes, incubations were carried out in laboratory conditions as well as field trials that allow to assess the dynamic of these nutrients in real conditions. Soil incubations under controlled moisture and temperature conditions to determine N mineralization are commonly used to estimate N availability for crops together with the environmental risk. Therefore, a laboratory incubation was conducted in order to determine the N mineralization rate of a compost made from wastes generated in the winery and distillery industries, widely distributed in Castilla-La Mancha, a region with significant problems of aquifers contamination by nitrates. Three increasing doses of compost corresponding to 230, 460 and 690 kg of total N per hectare were mixed with a sandy clay loam soil collected in this area. The evolution of mineral N in soil over time was adjusted to a nonlinear regression model, obtaining low values of potentially mineralizable N and low constants of mineralization, indicating that it is a material resistant to mineralization with a slow release of N, with only 1.61, 1.33 and 1.21% of total N applied being mineralized with each increasing dose of compost (for a period of six months). Furthermore, N mineralization after the application of this material was also evaluated in field conditions by carrying out a N balance during two growing seasons (2011 and 2012) of a melon crop under drip irrigation, a crop and management very characteristic of the area of study. The mineralization constants obtained in the laboratory were adjusted to the actual temperatures observed in the field to predict N mineralized during each growing season, however, this model generally overestimated the N mineralization observed in the field, because of the influence of other factors not taken into account for this prediction, as N accumulated in soil, the plant effect or the fluctuations of temperature and moisture. The fitting of the laboratory data to the model as well as the predictions of N mineralized in the field were better when considering N mineralized from the soil-compost mixture rather than when N mineralized from compost was isolated, underlining the important role of the soil on N mineralization from organic wastes. Since the area of study was declared vulnerable to nitrate pollution and is situated between different protected hydrological units, the risk of nitrate pollution after application of different doses compost was evaluated in the same field trial with melon under two irrigation regimes, irrigation adjusted to the crop needs (90 or 100% of the crop evapotranspiration (ETc)) or excedentary irrigation (120% ETc). Drainage was estimated weekly throughout the growing season by conducting a water balance, samples of the soil solution were taken and the concentration of nitrates was determined. To assess the risk of groundwater contamination associated with these practices, some environmental indices were used to determine the variation in the quality of drinking water (Impact Index (II)) and the nitrates concentration in the groundwater (Environmental Impact Index (EII)). To combine environmental parameters together with yield parameters, the Management Efficiency was calculated. It was observed that the application of compost under irrigation adjusted to the plant needs did not represent a higher risk of groundwater contamination even with the application of the highest doses. However, the application of large amounts of compost combined with an irrigation surplus represented an increase of N leaching during the growing season compared with the unamended plots, while no additional yield with respect to the adjusted irrigation strategy is obtained. The application of wastes derived from the winery and distillery industry as source of P was evaluated in calcareous soils characterized by a high P retention capacity, which in some cases limits the availability of this nutrient. Another incubation experiment was carried out using two soils with different texture, different calcium carbonate and iron contents and two levels of available P; to which different materials from these industries (with and without composting) were applied providing different amounts of P. Soil available P (Olsen P), pH and dissolved organic carbon were analyzed along time. At the end of the incubation, in order to study the changes in soil P status caused by the different residues, a fractionation of soil inorganic P was carried out, which was separated into soluble and weakly bound P (NaOH-NaCl- P), reductant soluble P or occluded in Fe oxides (CBD-P) and P precipitated as poorly soluble Ca-P (HCl-P); and the P retention capacity and degree of P saturation were determined as well. Given the calcareous nature of the soils, the influence of the amount of P applied with the organic wastes in soil available P only occurred at the beginning of the incubation period, while at the end of the trial the increase in soil available P equalled independently of the amount of P applied with each residue, increasing the P retained in the least soluble fraction when increasing P applied. Conversely, the application of less stabilized materials with a lower content of P resulted in an increase in the most labile P forms due to dissolution of P retained in the less labile fraction, demonstrating the influence of organic matter addition on soil P processes that control P availability in soil. As expected, the application of organic wastes increased the degree of P saturation in the soils, however the values obtained did not exceed the limits considered to pose a risk of water pollution. The influence of the application of organic wastes on inorganic and organic soil P forms was also studied in an acid loamy sand soil after long-term field application of cattle manure and biowaste compost and the combined application of compost and mineral fertilizer (triple superphosphate) in a crop rotation. Soil samples were collected 14 years after the establishment of the field experiment, and analyzed for soluble and available P, P sorption capacity, degree of P saturation and enzymatic activities (dehydrogenase, acid phosphatase and alkaline phosphatase). The different forms of organic P in soil were determined by using an enzyme addition technique, based on adding enzymes with different substrate specificities to NaOH-EDTA soil extracts, measuring the hydrolyzed P colorimetrically after an incubation period. The enzymes used were acid phosphatase, nuclease and phytase which allowed to identify hydrolyzable monoesters (monoester-like P) diesters (DNA-like P) and inositol hexakisphosphate (Ins6P-like P). The long-term application of organic wastes increased soil available P proportionally to the P applied with each type of fertilizer, assuming a higher risk of P losses given the high degree of P saturation of this soil. The application of organic wastes increased soil organic P resistant to enzymatic hydrolysis, but no influence was observed regarding the different forms of enzyme hydrolyzable organic P compared to those observed in the non-amended soil. Furthermore, the different forms of organic P applied with the organic wastes did not correspond to those analyzed in the soil which showed that these forms in soil are a result of multifaceted P turnover processes in soil affected by plants, microorganisms and abiotic factors. In this study, a correlation between Ins6P-like P and the microbial activity (dehydrogenase activity) of soil was found, which reinforces this claim. Finally, the application of organic wastes as a source of N and P in agriculture was evaluated agronomically in a real field scenario. A field experiment was established to evaluate the application of compost made from wine-distillery wastes in the same melon crop used in the experiments of N mineralization and leaching. In this experiment the application of three doses of compost were studied: 1 , 2 and 3 kg of compost per linear meter of plantation corresponding to 7, 13 and 20 tonnes of compost per hectare respectively; and the effect on plant growth, N and P accumulation in the plant as well as crop yield and quality was studied. The application of compost produced a slight increase in plant biomass accompanied by a significant improvement in crop yield with respect to the unamended plots, obtaining the maximum yield with the application of 2 kg of compost per linear meter. Although the potential effects of N and P were partially masked by other inputs of these nutrients in the system (high concentration of nitrates in the irrigation water and phosphoric acid supplied by fertigation), an effect of P was observed the first year of study resulting in a greater plant P accumulation and in an increase in the number of fruits in the amended plots. In addition, the higher accumulation of available N and P in the topsoil at the end of the growing season indicated the potential use of this material as source of these nutrients.