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Huertas familiares urbanas
No full textINTA desea llegar a la zona urbana con una propuesta de Huerta familiar o comunitaria donde se provee información de cultivo y consumo de hortalizas.Pro HuertaFil: Instituto Nacional de Tecnología Agropecuaria (INTA); Argentin
Germination and emergence of corn (Zea mays, L) as a function of soil physical parameters
Full text linkTesis para obtener el grado de Magister Scientiae en Soil Science, de la Oregon State University, en diciembre de 1988Rates of germination and emergence of corn were measured as influenced by soil physical parameters using blotter paper and a sandy loam soil as growth media. The corn seeds used were a hybrid of Funk's (DJ7xLH93). Experimental conditions were soil temperature of 20°C, 25°C, 30°C, and 35°C, soil water potential of -33, -100, -500, and -1000 kPa, soil bulk density 1.29 and 1.36 Mg/m³ and seeding depth of 3 and 7 cm. For the germination experiment seeds were put in contact with polyethylene glycol at solution concentrations to produce the desired water potentials. Treatment temperatures were maintained in a growth chamber and germination was evaluated every twelve hours. The number of hours required to obtain 50 and 80% germination was significantly increased by lowering either temperature or water potential. Although significant interactions were measured, temperature and water potential affected germination in different ways. Time to attain 80% of germination decreased as temperature increased until the optimum of 30°C was reached. Decreased osmotic potential levels progressively delayed and reduced germination. Time to germination increased greatly below -500 kPa. For emergence experiments seeds were planted in soil packed in covered containers which were placed in a growth chamber. Effects of soil temperature, soil water potential, bulk density, and seeding depth were evaluated. Bulk densities of 1.29 and 1.36 Mg/m³ , were achieved by no compaction and compaction. The two seeding depth were 3 and 7 cm. Time needed for emergence was influenced by soil temperature more than by any other variable. The time for emergence decreased progressively with lowering of soil water potential, lowering temperature or with increase in seeding depth. No significant differences resulted from increasing bulk density. In both the germination and emergence experiments, changes in temperature were more important than changes in water potential at high water potential. However this relation was reversed at water potentials lower than -500 kPa, where changes in water potential were more important than changes in temperature. The minimum time for both germination and emergence occurred at 30°C, at all water potentials. Effect of seeding depth was more important than effect of bulk density for time to emergence. Increases in time were between 20-30% as the seeding depth increased from 3 to 7 cm. Compaction began to limit seedling emergence at 1.44 Mg/m³.EEA Hilario AscasubiFil: Sanchez, Ramon Mauricio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Hilario Ascasubi; Argentin
Regulación de hormonas esteroides y metabolismo reductivo de la progesterona durante el desarrollo embrionario en los tejidos esteroidogenicos de Gallus Domesticus. Relación con la introducción de la δ-ALA-Sintetasa
Full text linkTesis para optar al título de Doctora en Ciencias Químicas de la Universidad de Buenos Aires, en 1986El tema de esta tesis obliga a tener en cuenta dos conceptos relativamente recientes en biología de la regulación humoral que, al tiempo de dar una visión más generalizada, por ende, integrativa, de los fenómenos hasta ahora observados, permiten esbozar hipótesis funcionales acerca de algunos hechos episódicos de la regulación, especialmente respecto de los picos y ritmos que se observan en la ecreción de hormonas y otros factores reguladores. La primera noción que se debe tener en claro a este respecto es que la regulación humoral., no es sólo endócrina, sino que también puede ser apócrina o autócrina, entendiéndose, dentro de este esquema, por endócrina, la que se produce entre tejidos, apócrina, entre células del mismo tejido o vecinas, y por autócrina la que ocurre en la misma célula. Las diferencias son; como se aprecia, bastante graduales, siendo así mismo difícil establecer un límite entre regulación autócrina y regulación metabólica dentro de una misma célula. El segundo concepto muy a tener en cuenta a los fines de esta tesis es el de las "fronteras móviles" de la endocrinología. Crece año a año, en efecto, el grupo de sistemas, tejidos y vías biosintéticas que demuestran ser reguladas, o por lo menos regulables por hormonas. En general nuestro conocimiento acerca de estas relaciones empieza por la medicina. Un ejemplo típico lo constituye el uso terapéutico de los glucocorticoides como
nmunosupresores antileucémicos y antiinflamatorios.Fil: Gonzalez, Claudia Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Characteristics and indices of reproduction in Dorper sheep
Full text linkIn seventeen adult Dorper ewes imported from South Africa into Israel and nine of their primiparous, first-generation daughters born in Israel, characteristics and indices of reproduction were determined during the period of April 1982 to April 1984. This study showed that, during the period from April 1982 to January 1984, three lambings occurred in the adult ewes; the lengths of the oestrous cycles for adult and primiparous ewes were 17.6 +/- 1.1 and 16.6 +/- 1.2 days, respectively; the number of services per ewe in oestrus were 3 +/- 1 services; the average length of pregnancy was 146-147 days; the lambing intervals were 6.2 +/- 0.46 and 7.7 +/- 0.62 months from the first to second lambing and the second to third lambing, respectively; of 17 ewes, 3 had twins in all 3 lambings (17.6%) and 4 had twins in only the first 2 lambings (23.5%). The sex ratio recorded in 70 lambs of adult ewes (in three lambings) was 41 males to 29 females (41:29). A high percentage of fecundity (137.2%) and prolificity (149%), an unrestricted breeding seasons, a short lambing interval and a short postweaning anoestrus period, recommend this breed of sheep as commercially advantageous for arid zones.EEA Rama CaídaFil: Elias, P. Ben-Gurian University of the Negev. Isan Centre for Comparative Medicine; IsraelFil: Cohen, D. Ben-Gurian University of the Negev. Isan Centre for Comparative Medicine; IsraelFil: Dayenoff, Patricio Mario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rama Caída; Argentina. Ben-Gurian University of the Negev. Isan Centre for Comparative Medicine; Israe
Instale un filtro portátil
No full textPro HuertaFil: Hernandez, Vicente. Instituto Nacional de Tecnología Agropecuaria (INTA). Pro Huerta; ArgentinaFil: Hidalgo de Avila, Elena. Instituto Nacional de Tecnología Agropecuaria (INTA). Pro Huerta; Argentin
Energía de "arriba" con el calefón solar
No full textEEA PergaminoFil: Cancelleri, María Nelly Lucy. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino; ArgentinaFil: Rodríguez, Jorge. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino; Argentin
The performance of N(1,1-dimethylpropynyl-3,5-dichlorobenzamide) and other herbicides in controlling weeds in lettuce as affected by soil type and weather conditions
No full textTesis de maestría para obtener el grado de Magister of Science presentada en Oregon State University en junio de 1970Chemicals are being sought that can control weeds in lettuce under different environmental conditions, soil types and weed populations. The extensive or repeated use of a herbicide may lead to important changes in the weed population which call for new materials that can take care of the modified situation.
In the search for new chemicais, RH 315 has appeared promising in some respects.
Greenhouse and field experiments were conducted to determine the tolerance of lettuce (crisphead type) to RH 315 in three types of soil. Its performance on weeds under different environmental conditions, its residual action on other vegetables, as well as preand postemergence activity on weeds wre also tested. Other herbicides were used in some experiments.
Lettuce of the crisphead type proved to possess high tolerance to RH 315. The tolerance was greater in a silty clay loam and a muck soil than in a sandy soil. In all. types of soil, the safety factor was greater than 2 X when susceptible weeds are considered. The degree of tolerance varied with the season in fieid experiments.
RH 315 at 1.5 to 2 lb/A in a silty clay loam and at 1 to 1.5 lb/A in a sandy loam provided excellent control of annual bluegrass, Italian ryegrass, bamyardgrass, green foxtail, common chickweed, purslane, mouseear chickweed, lambsquarters, henbit, red deadnettle, shepherspurse and bittercress. The control of pigweed and wild mustard required higher rates. No control of composite species was achieved with this compound.
Delaying sprinkler irrigation after application caused reduction in RH 315 activity. It was more effective in controlling weeds in early fail than during the summer.
Two months after application, RH 315 residues from rates which were effective in controlling susceptible weeds did not cause injury to bush beans, sweet corn, cucumbers, red beets, common chickweed and annual bluegrass, under summer conditíons.
When applied at the stage of two true leaves or before, under conditions of early fall, RH 315 proved to possess postemergence activity on weed species that are controlled by preemergence applications of this compound. From 17 to 20 days were required for RH 315 to exert its effect in postemergence application.
Trfluralin at 0. 75 ib/A provided excellent control of Itallan ryegrass, bamyardgrass, pigweedand purslane both in a silty clay loam and a sandy Ioam. Benefin and EL 179 both at 1 Ib/A gaye good control of the same weeds in the silty clay loam, but their performance was inferior to that of trifluralin. Benefin at 0.75 lb/A did not perform very well in the sandy loam.
Delaying incorporation 68 hours after the herbicide application caused 70% loss of trifluralin activity and 3510 loss of benefin action in a sandy Ioam soil. The residual action of triflurahn was greater than that of EL 179 and benefin when tested by vegetaMe plant growth 82 days after application. The least residual action was obtained with RH 315 and CDEC when tésted 60 days after application.
Bensulide at 6 lb/A performed poorly in a sii.ty clay loam, whereas CDEC at 5 lb/A provided good control of pigweed, Itallan ryegrass and barnyardgrass in the same type of soil.
The results obtained in this research showed that RH 315 Is effective for selective control of some weeds in léttuce that are not controlled by standard herbicides. Furthermore, its biological
residual life is sufficiently long to provide weed control for an entire crop cycle but not long enough to cause injury to succeeding, susceptible vegetable crops. The disadvantages of RH 315 are its poor activity Qn pigweed and its dependence on the supply of moisture immediately after application under summer conditions.Fil: Mitidieri, Agustín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; Argentin