Agronomía Costarricense 38(1)

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https://hdl.handle.net/10669/13980

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Agronomic and nutritional evaluation of african star grass-based pastures (Cynodon nlemfuensis) in the region of Monteverde, Puntarenas, Costa Rica. II. Nutritional Value
(2014-07-04 19:53:45) Villalobos Villalobos, Luis Alonso; Arce Cordero, José Alberto
The nutritional value of african star grass (Cynodon nlemfuensis)-based pastures was analyzed in 4 commercial dairy farms in the Monteverde region (latitude 10°20’, longitude 84°50’, 800 to 1200 masl), every other month during a 2-year period. Sampling was carried out in the paddock ready to be grazed and samples were hand-plucked leaving a 10 cm stubble height, simulating the consumption made by lactating cows. Average nutritional value for the 2 years was 23.57% DM, 20.27% CP, 2.67% EE, 10.97% ashes, 64.21% NDF, 34.95% ADF, 4.06% lignin and 68.02% IVDMD on a dry matter basis. Estimated energy content for the variables of TDN, DE, ME, NE L (3X), and NE G was 61.37%, 2.71, 2.05, 1.25 and 0.78 Mcal.kg -1 DM, respectively. Nutritional value of african star grass varied along the year, as it is sensitive to weather conditions. The farms with influence from the Pacific slope are less affected in forage quality than those with Atlantic influence. CP content was higher in this study than in previous evaluations for this species elsewhere and, in general, for tropical grasses as well. Protein is not a limiting factor for dairy cattle grazing african star grass, and its supply must use sources that allow an efficient utilization of soluble N by rumen microorganisms. The 25-day rotation systems in Monteverde must be flexible to allow, jointly with fertilization programs, the optimization of the productivity and persistence of the pastures.
Analysis of the potato crop nutrient status in Costa Rica, on the basis of existing information
(2014-07-04 19:53:45) Fallas Corrales, Róger Armando; Bertsch Hernández, Floria
An analysis of the potato leaf nutrient concentration in Costa Rica was made, from the results of foliar analyses conducted during the years 2006-2012 at the Soil and Foliar Laboratory of the Agronomic Research Center, University of Costa Rica (LSF-CIA/UCR). Also, through different literature sources, the potato crop’s nutrient sufficiency ranges established in different regions of the world were compiled. This information was compared with the percentaje of samples analyzed in Costa Rica and found below the critical concentrations reported in the literature. A large amount of samples were found below the critical concentration of nutrients B, Ca an Mg as defined in the literature, depending on whether the minimum or average literature results were used as a criterium for critical foliar level.
Body condition assessment in a grazing Jersey cows herd in the highlands of Cartago. Variations during the productive cycle
(2014-07-04 19:53:45) Saborío Montero, Alejandro; Sánchez González, Jorge Manuel
The aim of this research was to carry out a body condition score (BCS) observational study in a commercial grazing Jersey herd in Cartago, Costa Rica (9°55` N, 83°51` W, 2350 m of altitude). The study comprised 5864 BCS records from 122 cows (29 primiparous and 93 multiparous) over an 18 months period. Cows were scored weekly by the same person, from 9 th week prepartum to 43 th week postpartum. The 1 to 5 points scale was used (1=emaciated, 5=obese). Animal feeding practices were based on intensive grazing of 30 d regrowth kikuyu (Kikuyuocloa clandestina) and supplementation of a balanced concentrate according to physiological stage. Primiparous and multiparous cows BCS at calving was 4.01 points (95% CI: 3.80-4.22 points) and 3.83 points (95% CI: 3.71-3.94 points) respectively, BCS nadir after calving differed (p<0.05) between primiparous (3.10 points; 95% CI: 2.97-3.23 points) and multiparous cows (2.86 points; 95% CI: 2.76-2.96 points). When stratifying BCS at calving into values ≤3.25, 3.50 to 4.00 and ≥4.25 points, differences (p<0.01) were found in nadir and BCS change extreme values within primiparous or multiparous groups of cows. Animals that calved with higher BCS lost more BCS post calving, but remained at a greater BCS at nadir and the whole lactation. Results suggest that BCS at calving could be used as a partial indicator of BCS nadir and BCS change from calving to nadir, which has important implications on production and fertility of cows.
Characterization of visual symptoms of nutritional deficiencies in oak seedlings
(2014-07-04 19:53:45) Sepúlveda, Yira Lucia; Díez, María Claudia; Osorio, Nelson Walter; Moreno, Flavio Humberto; León Peláez, Juan Diego
The identification of visual symptoms of deficien- cies is a widely used method in the diagnosis of nutritional problems in agricultural and forestry production. The aim of this study was to charac- terize visual symptoms of deficiencies of N, P, K, Ca, Mg, S and B, in seedlings of the andean oak, Quercus humboldtii Bonpl., under nursery conditions. Seedlings were planted in polythene bags, where fertility treatments were applied according to the method of Jenny. After 4 months of development, we photographed seedlings and leaves with symptoms of nutritional deficiencies and determined leaf nutrient content. Deficiency symptoms were detected for all nutrients studied, except B. Seedlings deficient in each nutrient had lower concentration of this element in leaf tissues. The applied dose of P was apparently not enough to have an adequate availability of this nutrient and to generate an optimal development of seed- lings of Q. humboldtii under full fertilization.
Clay minerals identified in soils of Costa Rica from 1931 to 2014: I. History, methods of analyses, and mayor clay types found in volcanic ash derived soils
(2014-07-04 19:53:45) Alvarado Hernández, Alfredo; Mata Chinchilla, Rafael; Chinchilla, Miguel
Findings in a total of 84 research papers identifying clay minerals on 520 soil samples of Costa Rica are summarized. This review emphasizes on the clay minerals described in the topsoil samples, although clay minerals in the B horizons are also discussed when they are different to predominant mineralogy in the topsoil. Sites where soil clays information is available were geo-referenced, to observe their geographical distribution. In general most of the country possesses soil clays identified, except for the Nicoya Peninsula, the Northern Zone, and the Eastern Talamanca Range. Clay mineralogy suites (“predominant clay groups”) were grouped as: (1) vitrous-amorphous-halloysitic (Andisols and other soils with andic properties; (2) smectites and interstratified clays (Vertisols and other soils with vertic properties); (3) oxides- hidroxides-oxihidroxides-kaolinite-gibbsite (Alfisols, Ultisols and Oxisols); Plus a large area of soils with mixed clay mineralogy, found in places with little or no development (Entisols and Inceptisols). The soil clay genesis of the main clay types in the country is discussed when enough information was available.
Clay minerals identified in soils of Costa Rica from 1931 to 2014: II. Major clay types described in soils with vertic, and oxidic-kaolinic properties
(2014-07-04 19:53:45) Alvarado Hernández, Alfredo; Mata Chinchilla, Rafael; Chinchilla, Miguel
This paper summarizes available information on soil clay mineralogy in topsoils of Costa Rica, including clay minerals described in B horizons when significantly different from predominant mineralogy in the topsoil. The soil clay suites (“predominant clay groups”) emphasized are grouped as: (1) smectites and interstratified clays (Vertisols and other soils with vertic properties), and (2) oxides-hidroxides- oxihidroxides-kaolinite-gibbsite (in Alfisols, Ultisols and Oxisols). The soil clay genesis of these dominant groups is discussed when enough information is available.
Effect of sulpomag and organic complexs as partial substitutes of the culture medium used in the micropropagation of Musa sp. Cv. Cavendish
(2014-07-04 19:53:45) Montenegro Juárez, Frank E.; Rojas Idrogo, Consuelo; Quevedo Calle, David; Delgado Paredes, Guillermo E.
The Sulpomag natural fertilizer, or potassium sulfate and magnesium, constituted by K 2 O 22%, MgO 22%, S 18% and Cl (chloride) 2.5% plus organic complexes of coconut water 10 to 20%, and casein hydrolyzate 250 and 500 mg.l -1 , as partial substitutes for mineral salts of Murashige and Skoog (MS), were used in the in vitro propagation of banana, Musa sp., cv. Cavendish. The aim was that the in vitro plants grow and develop in minimum quantities of mineral salts, banned in the technical regulation for organic products. Shoot tips, established in vitro on MS medium, were transferred to 10 treatments for shoot multiplication supplemented with KH 2 PO 4 (170 mg.l -1 ), CaCl 2 .2H 2 O (150 mg.l -1 ), NH 4 NO 3 and KNO 3 , at 1/5 and 1/10 of the MS concentration, MS micronutrients and 0.1096 g.l -1 of Sulpomag, IAA (0.2 mg.l -l ) and BAP (5 mg.l -1 ). The rooting medium was the same formulation of mineral salts, only varying on the growth regulators. Best results were obtained in culture media supplemented with NH 4 NO 3 and KNO 3 at 1/5 of MS concentration, 0.1096 g.l -1 Sulpomag and coconut water 10 y 20%. The results allow to consider the possibility of using Sulpomag and coconut water, as partial substitutes for MS mineral salts for in vitro propagation of Musa sp., cv. Cavendish for use in organic agriculture.
Effectiveness of formic acid and thymol in the control of Varroa destructor in africanized honey bee colonies
(2014-07-04 19:53:45) Calderón, Rafael A.; Ramírez, Marianyela; Ramírez, Fernando; Villalobos, Ethel
The effectiveness of formic acid and thymol in the control of the mite Varroa destructor was evaluated from June to October 2011 in an apiary of 16 Africanized honeybee colonies (the colonies did not receive chemical treatment at all) located in Atenas, Alajuela. The apiary was randomly divided in three groups (A, B and C) of 8, 5 and 3 colonies, respectively. Group A was treated with 150 g of formic acid at 65%, group B received 2 applications of 25 g thymol and colonies of group C were used as control. Varroa traps were placed on the bottom board of each colony to collect the mites. After 4 weeks, all colonies were treated with 4 strips of flumethrin to kill the remaining mites and to assess the effectiveness of the products. Furthermore, the mortality of the different stages of varroa was evaluated in capped worker brood cells checking the pupa and the bottom of the cell for mites. The effectiveness of formic acid and thymol in the control of varroa mites was 94.7% and 96.9% respectively. In colonies treated with formic acid varroa mortality occurred mainly during 72 h after application, meanwhile in the roup treated with thymol the mite mortality was observed mainly one week after treatment. In addition, in the group of colonies treated with formic acid 86% of mite mortality occurred in capped brood cells, while in colonies treated with thymol and control colonies the varroa mortality in capped cells was less than 10%. In conclusion, the effectiveness of formic acid and thymol in the control of varroa mites was high, for which reason both products can be considered an alternative for the integrated management of varroa mites in Africanized honeybees colonies.
Foliar nutrient concentration in teak plantations at the Panama Canal watershed
(2014-07-04 19:53:45) Murillo Cruz, Rafael; Alvarado Hernández, Alfredo; Mark Verjans, Jean
Foliar concentration of macro- and micronutrients in teak plantations at the Panama Canal Watershed was measured on sites classed as high, medium, and low in growth (volume.ha -1 ). For the same purpose, plantations where grouped by age as young (3-4 years), medium (5-6 years) and late (7-8 years). Foliar macro-nutrients concentration followed the order N (1,9%), Ca (1.1%), K (0.7%), S (0.2%) and P (0.1%), while micro-nutrients concentrations decreased in the order Mn (50), Fe (43), Al (36), B (29), Zn (28), Cu (8), and Mo (0.4) mg.kg -1 . The K, P and Fe concentrations were clearly identified as low, while N, Ca, Mg and Mn values can be considered as marginal to slightly low. The Ca, Mg, N, K, Mn, Zn, Fe and Al concentrations varied statistically with plantation age in different ways; foliar concentrations of Ca, Mg, Mn, Fe and Al tend to increase with age, while those of N, K and Zn tend to diminish with age. Concentrations of Ca and Mn in the leaves of trees of sites with high and low growth differed statistically (p<0.01), with Ca values of 1.18% and 0.99%, in the high and low growth categories, respectively, and with Mn values of 41 and 65 mg.kg -1 in sites of high and low growth rates, respectively.
Mites associated with the avocado crop (Persea americana Mill) in the Central Coast of Peru
(2014-07-04 19:53:45) Muñoz Marticorena, Jorge Luis; Rodriguez Berrío, Alexander
Hass is an avocado cultivar grown in the central coastal region of Peru (Lima and Ica), with increasing economic importance, mainly to satisfy the high standards of foreign markets. This study (2010 to 2012, Central Coast), had the purpose to know the diversity of predatory mites in commercial avocado groves. Twelve Phytoseiidae species were registered, of which some would have potential as efficient predators of Olygonychus sp. These phytoseid species are: Amblyseius aerialis (Muma), Amblyseius chungas (Demmark and Muma), Amblyseiella setosa (Muma), Euseius emanus (El–Banhawy), Euseius concordis (Chant), Euseius stipulatus (Athias– Henriot), Phytoseiulus persimilis (Athias-Henriot), Phytoseiulus macropilis (Banks), Neoseiulus californicus (McGregor), Typhlodromina subtropica (Chant), Typhlodromus (Antoseius) evectus (Schusters) and Aristadromips n.sp. The presence of spontaneous vegetation, considered weeds for the avocado, plays an important role in the conservation of these predatory species on the cultivated trees. Also, the introduction of an exotic predator, such as Euseius stipulates, contributed significantly to the regulation of the Red Spiders Mites populations during the winter season.
Molecular characterization using rep-PCR of native isolates of Bacillus thuringiensis, obtained from soil samples
(2014-07-04 19:53:45) Galvis, Fabián; Yolima Moreno, Laura
Bacillus thuringiensis is a Gram-positive bacteria forming spores, which produces parasporal crystals of a proteic nature, toxic against various orders of insects and biodegradable and harmless to other species. This research use the experimental model, allowing, through observation techniques, microbiological and biochemical identification of B. thuringiensis from soil samples from municipalities of Cúcuta, El Zulia, Los Patios, San Cayetano and Villa del Rosario, Norte de Santander, Colombia, and its subsequent characterization with molecular markers Bc-Rep and MB1. Microbiological and biochemical tests identified 10 isolates as B. thuringiensis; the results of phylogenetic analysis showed significant differences in the clusters obtained with Bc-Rep and MB1 markers. With Bc-Rep a low index of similarity (18%) was recorded, while with the marker MB1 a higher similarity index, 58%, was obtained. This work indicated a great genetic variability among isolates, showing that markers Bc-Rep and MB1 are highly effective to differentiate closely related strains, thus becoming a genetic tool of great value for studies of identification and diversity in B. thuringiensis.
Phosphorous balance on Costa Rican dairy farms
(2014-07-04 19:53:45) Elizondo Salazar, Jorge Alberto; Jiménez Castro, José Pablo
The objective was to quantify P use in 11 dairy farms located in the provinces of San Jose, Cartago and Alajuela. Data such as feed purchases, milk sales, purchase and removal of animals between January and December 2010 were used. In order to evaluate the use of P, three indicators that allowed analyzing farm efficiency were used. Total number of animals ranged from 39 to 242. The average annual milk production was 300 880 kg. Farm area varied between 1 and 116 ha. The 11 farms imported on the average 1214 (±1036) kg of phosphorous: 70% came from feed, 16% from fertilizers and 14% from mineral supplements. The farms exported 294 (±219) kg of phosphorous, of which 90% was exported in milk sold and only 10% in animals sold. Total P exported ranged between 136 and 876 kg. Farms imported 4.1 (± 0.8) g.kg -1 P of milk produced. In general, P balance was positive for all farms, indicating that more P entered the farm that came out in the form of product, showing that 65% of imported P remained on the farms. Strategies to reduce P excretion should be aimed at reducing P in the diets, since the largest P input is through imported feed.
Root development in F1 coffe hybrids obtained by tissue culture
(2014-07-04 19:53:45) Echeverría, Fabián; Barquero, Miguel; Rodríguez, David
F1 Hybrid seedlings, obtained by indirect somatic embryogenesis, were acclimatizated under greenhouse conditions, separated in 2 types of container: biodegradable mesh with compressed turf (Jiffy®) and the other on conventional tray with soil and rice husk. Two months later, the plantlets were transferred to bags with conventional substrate and grown under nursery conditions. Development and quality of the plants were evaluated after growing during 8 months under conventional management. It was found that 33% had straight roots, however 65% had abnormalities, such as constrictions and loops, twists, bifurcations, among others, corresponding to lesser values in length, thickness and weight, both in the radical system as well as aerial. In regard to container type, acclimatizated plants grown in Jiffy® showed better growth than those in trays; however, those on which the cover was kept during the nursery stage were less developed, as compared to those were the cover was removed. It is recommended to remove the Jiffy® cover before planting in the soil bag in the nursery, and improve the temporary immersion technique to prevent morphological abnormalities of the embryos produced.
Soil enzyme activity -Dehidrogenase, ß-glucosidase, Phosphatase and Urease- under different crops
(2014-07-04 19:53:45) Henríquez Henríquez, Carlos Roberto; Uribe Lorío, Lidieth; Valenciano, Arturo; Nogales, Rogelio
The activity of 4 soil enzymes in farms under different agronomic managements and in different soil types was analyzed. The enzymes tested were phosphatase, β-glucosidase, dehydrogenase and urease. Soil samples were taken from the first 20 cm in depth, in order to determine the activity of the 4 enzymes and analyze them chemically. It was found that Dehydrogenase enzyme activity ranged from 0.13 to 4.46 with an average of 1.17 (μg INTF.g - 1 .h -1 ); β-glucosidase enzyme ranged from 31.9 to 208.1 with an average of 108.1 (μg PNP.g -1 .h -1 ). Furthermore, phosphatase had values between 413.4 and 3043.6 with an average of 1521.5 μg PNP.g -1 .h -1 , while Urease ranged from 12.5 to 52.8 with an average of 38.3 μg N-NH4.g -1 .h -1 . Phosphatase correlated with the percentage of organic matter and carbon in the soil (0.75 and 0.76 respectively, p<0.01); an inverse relationship was found between the activity of this enzyme and the content of available P (-0.53r, significant at p<0.10). Urease correlated with phosphatase (r=0.61 p<0.05) and with dehydrogenase (r-0.77 p<0.01). Multivariate cluster analysis based on the enzymatic activity allowed to make similar groups according to the type of crop, which shows the potential of usage that this property has for undertaking more detailed studies.
Supplementation with organic selenium and its effect on productive and reproductive performance in grazing dairy cows in Costa Rica
(2014-07-04 19:53:45) Sánchez Salas, Jeffry Gerardo; Elizondo Salazar, Jorge Alberto; Víquez Matei, Evelio; Orozco Vidaorreta, Carlos
The objective was to evaluate the effect of supplementation with selenized yeast, derived from a specific strain of Saccharomyces cerevisiae (CNCM I-3060), on productive and reproductive performance and on selenium concentrations in milk of grazing dairy cows. Multiparous Holstein cows (n=40), with an average body weight of 607±62 kg and a body condition score of 2.9±0.2 before parturition, were randomly assigned to 1 of 2 treatments. Control treatment consisted of a basal diet supplying 0.7 mg of Se.kg -1 dry matter. Experimental treatment consisted of the same basal diet supplemented with 3.0 mg of Se, from day 5 to 56 of lactation. Milk production, milk composition, SCC, and Se content of milk were determined at day 5, 14, 28, 42, and 56 of lactation. Blood samples from each cow were also taken during the same days, to measure glutathione peroxidase (GSH-Px) and Se concentration. To evaluate reproductive performance, the ovaries were examined by transrectal ultrasonography at days 22 and 57 postpartum. Days open, days to first service and services per conception were also recorded. Milk production, milk composition, and SCC did not differ between treatments during the trial. Selenium supplementation did not alter GSH-Px concentration (199.0 vs. 220.3 U.g -1 Hb) or Se concentration in blood (166.4 vs. 184.2 μg.l -1 ). However, organic selenium supplementation increased (p<0.01) Se apparent efficiency of transfer into milk (7.9 vs. 9.9%) and Se content of milk (12.7 vs. 20.5 μg.l -1 ); therefore, milk derived from cows supplemented with selenized yeast could be a useful way to contribute to daily intake of Se in humans, allowing to reach the daily dietary recommendations and helping as a functional food to solve problems related to Se deficiency.
Verification of dry matter content as indicator of harvest for Hass avocado fruits (Persea americana) grown in intermediate elevation production areas at Los Santos, Costa Rica
(2014-07-04 19:53:45) Cerdas Araya, María del Milagro; Montero Calderón, Marta; Somarribas Jones, Omar
The objective of this research was to study whether avocado dry matter content (DMC) could be used as an appropriate harvest index in substitution of fruit oil content (OC), for Hass avocados grown in intermediate elevation areas (1750 masl) at Los Santos geographical region, Costa Rica. A total of 2000 pollinated flowers were tagged in 100 trees after fruit set. Thirty five fruits were evaluated each week, from week 31 to 44. It was found that both, OC and DMC, showed a rapid and significant increase after week 39 (p≥0.05), with a correlation coefficient between them of 0.92. Other observed simultaneous changes, related to fruit ripening, were the development of skin purple color (covering 74% of the surface area), the reduction of the adherence of the seed coat to the fruit pulp, and of the skin and seed to the pulp, as well as the decrease of the fruit firmness, from 118 N during the 31st week down to 57 N at week 40 and beyond. The use of 23% DMC in fruits is recommended as a harvest index for Hass avocado in Los Santos growing area, as an alternative to fruit oil content (OC).

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