Subsurface drip irrigation emitter spacing effects on soil water redistribution, corn yield and water productivity

Emitter spacings of 0.3 to 0.6 m are commonly used for subsurface drip irrigation (SDI) of corn on the deep, silt loam soils of the U.S. Great Plains. Subsurface drip irrigation emitter spacings of 0.3, 0.6, 0.9 and 1.2 m were examined for the resulting differences in soil water redistribution, corn grain yield, yield components, seasonal water use, and water productivity in a 4���year field study (2005 through 2008) at the Kansas State University Northwest Research���Extension Center, Colby, Kansas. The results indicate that there is increased preferential water movement along the dripline (parallel) as compared to perpendicular to the dripline and that this phenomenon partially compensates for wider emitter spacings in terms of soil water redistribution. Corn yield and water productivity (WP) were not significantly affected by the emitter spacing with application of a full irrigation regime

Impact of chlorophenols and heavy metals on soil microbiota: their effects on activity and community composition, and resistant strains with potential for bioremetiation

Pollution by toxic compounds is one of the most relevant environmental damages to ecosystems produced by human activity and, therefore, it must be considered in environmental protection and restoration of contaminated sites. According to this purposes, the main goal of this doctoral thesis has been to analyse the impact of several chlorophenols and heavy metals on the microbial communities of two typical Mediterranean soils. The ecological risk concentrations of each pollutant, which have been determined according to respirometric activity and changes in the microbial community composition, and the factors that influence on their effective toxic concentrations (bioavailable pollutants) have been analysed in order to predict their potential impact on different soil ecosystems and provide scientific data for the regulation of the soil protection policies. Moreover, resistant microorganisms with pollutant removal capacities have been isolated from artificially contaminated soil microcosms and tested in axenic cultures, to infer their potential usefulness for bioremediation.

Characterization and efficacy of bacterial strains for biological control of soil-borne diseases caused by Phytophthora cactorum and Meloidogyne javanica on Rosaceous plants

S'avaluaren 58 soques de Pseudomonas fluorescens i Pantoea agglomerans per la seva efic��cia en el biocontrol de la malaltia causada per l'oomicet Phytophthora cactorum en maduixera i pel nematode formador de gal��les Meloidogyne javanica en el portaempelt GF-677. Es desenvolup�� un m��tode ex vivo d'inoculaci�� de fulla amb l'objectiu de seleccionar soques bacterianes com a agents de control biol��gic de P. cactorum en maduixera. Tres soques de P. fluorescens es seleccionaren com a soques eficaces en el biocontrol del patogen en fulles i en la reducci�� de la malaltia en plantes de maduixera. La combinaci�� de soques sembl�� millorar la consist��ncia del biocontrol en comparaci�� amb les soques aplicades individualment. Tres soques de P. fluorescens es seleccionaren per la seva efic��cia en la reducci�� de la infecci�� de M. javanica en portaempelts GF-677. La combinaci�� d'aquestes soques no increment�� l'efic��cia del biocontrol, per�� sembl�� reduir la seva variabilitat.