V.12 (2) p. 14-20 | Sergio Rodríguez y Jorge Romero | 65767 | Dat. Num. | Temas Agrarios (Colombia) | (Jul - Dic 2007)

Frijol | V.5 (9) p. 61-72 | Arroz | Maíz | Dat. Num. | Jorge Romero F. y otros | 65768 | (Ene - Jun 2000) | Temas Agrarios (Colombia)

Potassium is a macronutrient that can improve the growth of crops. A randomized complete block design was used to evaluate the influence of four planting densities (50,000, 41,667, 33,333, 31,250 plants ha-1) and three potassium levels (300, 250, 200 kg of K2O ha-1) on leaf area (AF), leaf area index (LAI), crop growth index (CCI) and harvest index (CI) in potato Solanum tuberosum Phureja var. Criolla Guaneña grown in an area of Botana, Altiplano de Pasto, Nariño, Colombia. All evaluations were measured every 20 days until 120 days after sowing (das), except for the IC at the end of the cycle. Analysis of variance, comparison of Tukey means (P<0.05) and regression among the evaluated variables was performed. The physiological variables presented a significant adjustment to the polynomial models of third degree, quadratic and Hoerl, with coefficients of determination higher than 0.6, indicating that with 31,250 plants ha-1 and 250 kg K2O ha-1 increments were achieved in AF of 6000 cm2 and with 200 kg K2O ha-1 in IAF and ICC of 2.0 and 40 g m2 day-1 between 60 to 80 and 80 to 100 das, respectively; However, with 33,333 plants ha-1 and 250 kg K2O ha-1 the IC (0.70) was increased (P<0.05). Although the regressions showed a tendency to increase the LAI and ICC with the production management practices carried out by the farmers (41,667 plants ha-1 and 250 kg K2O ha-1) between 60 to 80 das, it is not recommended since a lower IC (0.60) was obtained at the end of the cycle.

The objective of this research is to propose a model to articulate Colombian horticultural production chain as a mechanism for managing the interactions between actors for the flow of materials with the cold chain as a logistic-technological tool for the conservation of perishable foods. Based on a sequential construction methodology, a link and segment model is proposed for the Colombian horticultural sector. The model integrates the activities from the input suppliers to the final customer or consumer, identifying their descriptors. Consequently, the cold chain models proposed in the literature are conceptualized and characterized trough a critical control point’s analysis (exogenous and endogenous), based on the HACCP system, selecting the synchronized supply chain model. The joint and superimposed analysis of these two models becomes the articulated design, which allows directing the adaptation of technology in transportation and storage of products under appropriated cold chain conditions for fruits and vegetal products as a competitive advantage.

The economic analysis of technological options is a complement to biophysical research. The objective of this work was to estimate the economic advantages of incorporating new varieties of cotton, to reduce the production costs of cotton in the Sinú Valley, department of Córdoba, and to make the crop more competitive; since the surface harvested in Colombia in 2015 decreased by 39%, due to the high production costs of more than 5 million per hectare and low yields of 680 kilos of cotton fiber per hectare with losses of $ 1,157,827 Colombian pesos. Among the limitations of production are the attacks of pests and diseases, especially the cotton weevil (Anthonomus grandis) and the ramolosis, which participate in 60% of production costs. It is concluded that the introduction of genotypes with tolerance to the mentioned phytosanitary problems, will contribute in the increase of the productivity of the crop.

The emergence of cooperative groups created by companies with a co-operative status, upstream production, and private companies resulted in the rupture of their relationship with their members. This paper addresses the role of agricultural consultation in strengthening the relationship between cooperatives and their members in order to resolve the inherent identity crisis of such groups. A qualitative method based on the case study of five groups allowed us to study the interactions between communities through a new mode of knowledge management characterised by the interaction between functional groups and communities of practice: the Model 3. We show that agricultural advisors act as translators between the two cognitive communities and this facilitates the resolution of the identity crisis of agricultural cooperatives.

This study involves the evaluation and classification of climate and soil resources in Valencia Cordoba, using geographic information systems. Climate component data from five meteorological stations with records of precipitation, temperature, relative humidity and solar radiation were used. Edafológic component data were obtained from 119 soils analyzes of the growing of papaya. To generate mapping spatial distribution of climatic and soil variables interpolation method of inverse distance weighted incorporated into the ArcMap program was used, this process led to the mapping of variables spatialized on a scale of 1: 250,000. By this method delimited by isolines in climate and soil variables they were calculated areas. To perform the mapping of areas with productive capacity a scale of four categories that involve the variables of soil pH, MO, texture, P y Al, which privileges the A1 was used: Very best, A2: excellent, A3: A4 optimal and slightly: moderately optimal. As a result we obtained the very best areas (A1), representing 4.6% (3,050 ha), located in the northern part of the area that optimal areas (A2) comprise 55% (36,440.7 ha), located in the central sector of the reference area, slightly optimal areas (A3) (23,533.6 ha) and represent 35.5% of the total area, located in the southeast part and 4,7%, (3156.5 ha) has been categorized as slightly optimal (A4) are located in the southwestern part of the study area.

The root rot of avocado, is a devastating disease in all cultivated areas of Colombia and worldwide. In nurseries and during the first two years of establishment of the crop it is reported losses between 30 and 50% and in the field, incidences of the disease up to 75% are reported. The review is focused to propose alternatives of Integrated Management of the Disease, IDM, involving practices based on four basic principles: sanitation, cultural and biological management, use of resistant root stocks and chemical control. Sanitation, involves all the measures to reduce the possibility to introduce the disease in nurseries, such as: a) sterilization through vapor and use of fumigants in the substrate, b) good ventilation, c) good drainage, and d) seed treatment with hot water or systemic fungicides. The cultural and biological management, refer to development of cultural and biological practices to reduce the incidence of the disease, as planting of seedlings in mounds and application of fungi, such as Trichoderma harzianum, respectively. The use of resistant root stocks, such as Martín Grande G755a, G755b, and G755c, from Guatemala, NATU-001 and CANO-008 from Colombia, and Duke 6, Duke 7 and Thomas, from México, is the best alternative to control the disease, complemented with rational use of protectants fungicides before transplanting of the group of dithiocarbamates and systemics in the field of the groups acylalaninas and phosphonates, such as metalaxyl and fosetyl-Al, respectively. All these practices are focused into the logistic model of Van der Plank.

The root rot of avocado, is a devastating disease in all cultivated areas of Colombia and worldwide. In nurseries and during the first two years of establishment of the crop it is reported losses between 30 and 50% and in the field, incidences of the disease up to 75% are reported. The review is focused to propose alternatives of Integrated Management of the Disease, IDM, involving practices based on four basic principles: sanitation, cultural and biological management, use of resistant root stocks and chemical control. Sanitation, involves all the measures to reduce the possibility to introduce the disease in nurseries, such as: a) sterilization through vapor and use of fumigants in the substrate, b) good ventilation, c) good drainage, and d) seed treatment with hot water or systemic fungicides. The cultural and biological management, refer to development of cultural and biological practices to reduce the incidence of the disease, as planting of seedlings in mounds and application of fungi, such as Trichoderma harzianum, respectively. The use of resistant root stocks, such as Martín Grande G755a, G755b, and G755c, from Guatemala, NATU-001 and CANO-008 from Colombia, and Duke 6, Duke 7 and Thomas, from México, is the best alternative to control the disease, complemented with rational use of protectants fungicides before transplanting of the group of dithiocarbamates and systemics in the field of the groups acylalaninas and phosphonates, such as metalaxyl and fosetyl-Al, respectively. All these practices are focused into the logistic model of Van der Plank.

Los sistemas de monocultivo degradan el suelo afectando sus propiedades físicas y químicas, y su regeneración es muy lenta. Con el objetivo de conocer cambios en las propiedades físicas del suelo de la Estación Experimental Tropical Pichilingue, por efecto del uso, se empleó un diseño de bloques completos al azar con tres repeticiones, en los suelos de bosque nativo y monocultivos de maíz (30 años), cacao (50 años), pasto (4 años) y palma aceitera (26 años) en diferentes profundidades cada 0,10 m hasta los 0,6 m. Se evaluaron propiedades físicas como conductividad hidráulica, densidad aparente, densidad real, porosidad total, porosidad de aireación, humedad volumétrica, textura, arcilla dispersa en agua, grado de floculación, materia orgánica e índice de materia orgánica/ limo+arcilla. Los datos fueron analizados estadísticamente y se realizó la prueba de Tuckey (P≤0,05). Se encontró que maíz, palma aceitera y pasto provocaron incrementos estadísticos significativos en la densidad aparente del suelo sin llegar a sobrepasar los niveles críticos de 1390 kg m-3 y no significativos en reducción de la porosidad total en la profundidad de 0,1-0,2 m. También, hubo alta concentración de arcillas en las primeras profundidades de los suelos cultivados, que provocó susceptibilidad a los procesos de erosión hídrica, concluyendo que el suelo bajo cultivo de palma aceitera mostró mayores diferencias estadísticas debido a la textura, afectando negativamente la densidad aparente del suelo, conductividad hidráulica, arcilla dispersa en agua, que en suma contribuyen a disminuir la estabilidad de agregados.