Agronomía Costarricense 36(2)

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  • Ítem
    Análisis financiero para la implementación de un sistema estabulado en una finca de ganado de leche en costa rica
    (2013-05-14 00:00:00) Villalobos Villalobos, Luis Alonso; Rivera, Leonardo
    Financial analysis for the implementation of a feedlot in a dairy cattlefarm in Costa Rica. The financial feasibilityfor the implementation of a feedlot in a dairyfarm was evaluated. The evaluation was madein the functional departments (production,marketing, human resources and finances) todetermine the technical situation before changingthe productive system. The reproductive andproductive records were used to map out thegrowing of the herd with the program Invest-GA®. Financial analysis was carried out bysearching for market information, estimating theborrowing capacity of the company and nominalcash flows made from financial records of theDairyProfit® program. The net present value(NPV) was obtained as a financial indicatorfrom the different projections. A sensitivityanalysis was made varying the production levelof the animals (one-dimensional), and a marginalanalysis was made by using the incremental NPVobtained in the projections versus the productivesystem without investments. The best projectionfor the dairy farm was the investment in a stable,a mixer and receiving a lower payment for theadditional milk delivered to the factory obtaining¢237.129.530,15 and ¢89.169.075,85 for the NPV and incremental NPV, respectively. The receivingof the product by the dairy factories is one ofthe main factors affecting the implementation ofmore intensive systems in the dairy farms of CostaRica. Productivity of dairy farms determines theircompetitiveness, because as the specialization indairy production systems grows, there are moreexternal factors that may affect performanceand, therefore, internal control systems must beaccurate to adapt to the current situation.
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    Evaluación del residuo de cáscara de nuez (Juglans regia L.) en la producción de plántulas de Pinus patula, en vivero
    (2013-05-14 00:00:00) Romero Arenas, Omar; López Escobedo, Romelia; Damián Huato, Miguel Angel; Hernández Treviño, Israel; Parraguirre Lezama, José F.C.; Huerta Lara, Manuel
    Evaluation of residue of rind of nut(Juglans regia L.) in production of seedlings ofPinus patula, in pond. To produce quality plantsin the nursery, commercial substrates such asthe Peat Moss, perlite and vermiculite, are used;their cost is high and significantly reduces profitmargins; thus, there is a need to find alternativesubstrates. The shell of the walnut (Juglans regiaL.) is a residue without use in production; yetit has important nutrients that can be used byplant organisms. This study evaluated the initialgrowth of Pinus patula produced in the nursery,using compost of walnut shell with vermiculiteand perlite, gradually replacing the Peat Moss.A completely randomized design was used tocompare 4 treatments based on nutshell + perliteand vermiculite, in proportions ranging from 0%to 80% walnut shell, and the mix of commercialsubstrates. At 7 and a half months of age, theseedlings that developed in treatment 1, controlmixture (Peat Moss 33% + vermiculite 33% +perlite 33%) and treatment 4 (Nutshell 33% +vermiculite 33% + perlite 33%) showed highervalues in the variables: height, diameter, shoot dry weight, root dry weight and total dry weight.The relation shoot/root and the slenderness ratiodid not differ among the 4 treatments. The highestvalue of the Dickson quality index was for thecontrol (0.25, followed by treatment 4(0.24, without statistical differences. Thewalnut shell allows to produce healthy seedlings,making it useful as an alternative substrate forproduction in nursery plants, reducing productioncosts and contributing to the forest production sector.
  • Ítem
    Herramientas para un programa de mejoramiento genético del guayabo (Psidium guajava L.) en Cuba
    (2013-05-14 00:00:00) Valdés Infante, Juliette; Nerdo Rodríguez, Narciso; Velásquez, Josefa Bárbara; Sourd, Darío Gaspar; González, Gonzalo; Rodríguez, Julio Alberto; Rohde, Wolfgang
    Tools for a genetic breeding programfor guava (Psidium guajava L.) in Cuba. Theobjective of this work is to develop a genetic improvement program for guava (Psidium guajavaL.) in Cuba, which may contribute to a moreefficient use of its genetics resources. It beginswith the establishment of the collection, takinginto account the prospection of native genotypes,as well as the introduction of wild relatives and accessions with a diverse geographical originfrom the main producer countries. These activitiesare vital for the posterior collection enrichmentand maintenance, as well as the different sexualand asexual propagation procedures, whichguarantee material multiplication and allow tocreate new variability sources. Once established,characterization can proceed. For this, a groupof minimum descriptors that can be useful tohomogenize such studies to an international leveland for cultivar catalogues confection are referredto, the latter of great demand from producers andspecialists. For a rational germplasm managementit is necessary to know the existent variability. Inthis sense, highly discriminative morphologicalcharacters, as well as AFLP and SSR molecular markers, are recommended, whose combinationallows to identify accessions and to form diversity groups, not only in guava but also in other Myrtaceae members. All this integral analysisguarantees a more efficient selection processof promissory genotypes for different purposes (breeding, conservation and commercialization).From them, crosses that can serve to evaluatehybrids with desirable commercial characteristicsare recommended, as well as the development of agenetic linkage map and QTLs association, as thea step towards a future marker-assisted selection implementation. The role of tissue culture is also stressed, as an alternative conservation method and for guava improvement, considering the mainresults obtained in the country.
  • Ítem
    Efecto de la rotación de cultivos en la incidencia del amachamiento (aphelenchoides besseyi christie) en frijol
    (2013-05-14 00:00:00) Chaves Barrantes, Néstor Felipe; Araya Fernández, Carlos Manuel
    Effect of crop rotation in the incidenceof “amachamiento” (Aphelenchoides besseyi Christie) in common bean. The effect of crop rotation on the incidence of common bean “amachamiento” was evaluated in the “Brunca” region in Costa Rica during 2009 complemented by a field observation during 2010. The incidence of “amachamiento” in 2009 was quantified in vegetative (V3 or V4), flowering (R6) and pod-production (R8) plant growth stages, in bean commercial fields rotating with previous rice, corn, hot-pepper, pumpkin or bean. Four micro-plots (10 m2) were established in each field; to score “amachamiento” incidence, data were subjected to angular transformation and statistical means among treatments were separated by ANOVA. The 2010 field observation was developed in a farm growing common beans on soils previously planted with either ginger, taro or corn. In 2009, during the R8 growth stage a minimum incidence was detected in the hot-pepper-bean rotation (4%), intermediate levels inthe pumpkin-bean (15%) and rice-bean rotation(29%), and high incidence in both bean-bean(62%) and corn-bean (64%) rotations. In the 2010 field observations, during the floweringstage “amachamiento” incidence was 4% in the ginger-bean rotation and 5% in the taro-bean one, significantly lower than in the corn-bean rotation (25%). Based on these results, crop rotations suchas hot-pepper, ginger, taro or pumpkin precedingcommon bean can reduce both “amachamiento” incidence and, consequently, yield losses.
  • Ítem
    Efecto del consumo de dieta líquida y alimento balanceado sobre el crecimiento y desarrollo ruminal en terneras de lechería
    (2013-05-14 00:00:00) Elizondo Salazar, Jorge Alberto; Sánchez Álvarez, Melissa
    Effect of liquid and solid diet intakeon growth and rumen development of dairycalves. The objective of this study was todetermine the effect of liquid and solid dietintake on growth and rumen development ofdairy calves. The experiment was conducted in acommercial dairy farm located at 2500 m.a.s.l inthe province of Cartago, Costa Rica. Ten Holsteincalves were selected at birth and randomlyincluded in 1 of 2 treatments. The conventionaltreatment consisted in providing calves a liquiddiet on a restricted basis (4 l.calf-1.d-1). Theintensive treatment consisted in supplying calvesthe same liquid diet in larger quantities, up to8 l.calf-1.d-1. Growth measurements includingbody weight, hip height and withers height weretaken weekly. Calves were sacrificed at 8 weeksof age, in order to compare rumen growth anddevelopment. Animals in the intensive treatmenthad a significantly higher liquid diet intake andlower feed intake than calves in the conventionaltreatment. Growth measurements showed nosignificant differences between treatment groups.Calves in the intensive treatment had a poorrumen development and lesser papillae growth, which may negatively affect calves’ post-weaning performance.
  • Ítem
    Manejo sostenible de la broca del café (Hypothenemus hampei) mediante poda sistemática del cafeto en Costa Rica
    (2013-05-14 00:00:00) Rojas, Mainor
    Sustainable management of coffee berryborer (Hypothenemus hampei) by systematicpruning of coffee plants. Assessments wereperformed in 29 coffee plantations in 9 locationsin Costa Rica and a field trial was conducted,with the purpose of studying the behavior of thecoffee berry borer attack in plots with differentpruning systems and validating the differentiatedpest control in a row-pruning (every 3 years)system. The assessment of the coffee berry borer,in sites where pruning is performed per plot every3 years, showed a reduction of 48 percent in theattacks to 1-year branches in relation to the 2-yearbranches; in plots where row pruning is performedevery 4 years, attacks were 52 and 65 percent lessin 1 and 2-year branches than in 3-year branches. A similar effect was observed in plots with rowpruning every 3 years, where 1-year branches hadan average of 56 percent less attack than 2-yearbranches. In the field trial, after the differentiatedapplication of insecticide, the percentage of fruitswith coffee berry borers alive in the 2-year rowwas of 0.7 percent in both treatments at 90 daysafter application; whereas in the 1-year row thispercentage was 0.7 percent where the insecticidewas applied and 1 percent where it was notapplied, with no significant differences betweentreatments. The differentiated control of the coffee berry borer, in a pruning system per rowperformed every 3 years, made it possible to save30% in application time, 40% in insecticide and36.5% in water used for aspersion, by making theapplication to only 33% of the coffee plantation,and without putting into risk the rest of the areacultivated. It was concluded that pruning perplot, as well as per row, makes it possible toconcentrate the coffee berry borer in small areasof the coffee plantation, which contributes to pestcontrol management.
  • Ítem
    Curvas de absorción de nutrimentos para tres variedades de lirios (lilium sp.) y afinamiento del programa de fertilización en una finca comercial en Heredia, Costa Rica
    (2013-05-14 00:00:00) Barrantes Infante, Bianca L.; Bertsch Hernández, Floria
    Nutrient absorption curves in three lily(Lillium sp.) varieties and optimization of afertilization program in a commercial farmin Heredia, Costa Rica. The fertilizer programwas evaluated and optimized in a lily commercialfarm, after the development of nutrient absorptioncurves in the varieties Brunello, Algarve andAlma Ata. The lily plants were separated intoorgans to evaluate the fresh and dry at 80oCweights, every 15 days, in 3 plants per variety.Dry tissues underwent concentration analysis toobtain the nutrient absorption. Based on nutrientabsorption curves 5 fertilization treatmentswere designed: a treatment that consisted in thefertilization program of the commercial farm;the requirement treatment; which included onlywhat the plant absorbs; an adjusted treatment,a treatment without any granular application;and the control. These treatments were appliedto the Siberia variety during the growing cycle.The absorption curves showed that most of thenutrients are provided by the bulb during the first4 weeks of a total cycle of 12 to 14 weeks. Thecontents of N, P and K in the bulbs at the momentof planting ranged from 144-178, 19-28 and 160- 174 mg.bulb-1, respectively, while for a production of 66 (Alma Ata) and 72 (Brunello and Algarve) shoots.m-2 the aerial part of the plant consumed 15-18, 1.2-1.6 and 26.7-40.3 g.m-2, respectively. In all varieties, the highest absorption of N, P and K occurred at the end of the life cycle. Therequirement treatment did not show significantdifferences from the treatment of the commercialfarm, presenting the same level of production andquality; also, it produced the highest number ofmedium and large size plant with a commercialvalue. The requirement and adjusted treatmentsshowed the highest number of large buttons(>5 cm). Foliar applications of fertilizers provedto be important, mainly because the treatmentwithout any granular fertilizer application hadthe highest percentage (56%) of bulbs andadventitious roots with the best appearance.
  • Ítem
    Nuevos hospederos y registros de ácaros fitófagos para Costa Rica: período 2008-2012
    (2013-05-14 00:00:00) Aguilar Piedra, Hugo Gerardo; Murillo, Pamela
    New hosts and records of plant feedingmites for Costa Rica: interval 2008-2012.The phytophagous mite species identified forCosta Rica from 2008 to 2012 are updated.Plant material provided by growers, technicians,students, and interested public, as well as thatcollected by Laboratory of Acarology staff, wasidentified. Sixty-three new host plants groupedin 29 families, for 5 families of phytophagousmites, are mentioned. Tetranychus urticae,family Tetranychidae, was the second species asto number of hosts, being found on 12 new plants.Moreover, other species within the family werefound, i.e. Eutetranychus banksi, Mononychellusplanki, Oligonychus peronis, O. pratensis, O.punicae, O. ununguis, O. yothersi, Paraponychuscorderoi, Tetranychus cinnabarinus, T. ludeni,T. mexicanus, and 3 species in this genuswhich were not identified. Four species in thefamily Tenuipalpidae are recorded: Brevipalpuscalifornicus, B. gliricidiae, B. obovatus, andB. phoenicis. Within the family Tarsonemidae,Phytonemus pallidus is reported, as well asPolyphagotarsonemus latus, with 15 newregisters, the species with the largest numberof hosts on this new period; Steneotarsonemusananas is also reported, associated withpineapple. From the family Eriophyidae, Abacarus doctus, recently described as a newspecies, is reported associated with sugarcane inthe country; likewise Calepitrimerus muesebecki,related to avocado, and 2 species of exposed,un-described eriophyids. Retracrus johnstoni,family Phytoptidae, was collected from Heliconialatispatha, family Heliconiaceae, first record of amite in this genus associated with a family otherthan Arecaceae. Lastly, field diagnosis is alsooffered for some chosen species within the 5families studied.
  • Ítem
    Análisis del crecimiento de cinco híbridos de zanahoria (Daucus carota l.) mediante la metodología del análisis funcional
    (2013-05-14 00:00:00) Vega Rojas, Tatiana; Méndez Soto, Carlos H.; Rodríguez Montero, Werner
    Plant growth analysis of five hybridsof carrot (Daucus carota L.) by functionalanalysis methodology. Plant growth analysisof 5 hybrids of carrot (Daucus carota L.) wasconducted in Cipreses, Oreamuno, Cartago, withthe aim to describe the phenology and growth ofcarrot. Growth analysis was performed using themethodology of functional analysis. The leaf areaand the dry weight of each organ and total plantwere evaluated, non-linear regression modelswere adjusted for these variables, the parametersthat define the mathematical functions that bestdescribe the growth were obtained and each modelwas plotted for each variable evaluated. The rootsand total dry weight variables were adjusted to anasymptotic nonlinear logistic function: PS=alpha/(1+exp (-beta (x-gamma))); the leaves dry weightand the leaf area were adjusted into the bell-type function: PS=alpha*exp (-beta (x-gamma)2).Plants showed a sigmoidal growth curve withwell-defined stages: a slow growth phase, thenan exponential growth segment, followed by aperiod of reduced growth and finally a stageof stability. The plant spends its early stages of development establishing the photosyntheticmachinery, indirect competition with radicaldevelopment. The root begins to thicken between63-77 dap, during the second phase of growth,with a greater proportion of assimilates allocatedto the root, leading to an increase in its diameter.Finally, from the analysis of the variables oftotal dry weight and leaf area, 2 groups can beestablished: on the one side Supreme, Esperanzaand Bangor, and on the other CLX-3193 andSirkana. The first group showed the highestvalues for such variables.