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Determination of the factors that change the energy consumption for irrigation with Pivot electric power machines, was carried out in the “Valle del Yabú" Agricultural Company. By using as a case study aWestern brand irrigation machine, with four towers and a irrigated area of 18.2 ha, hydropower of 1.35 L/s/ha, flow rate of 23.45 L/s and an efficiency of 85% according to the manufacturer. The study was performed during irrigation activity in potato cultivation. During theinvestigation, an evaluation of the irrigation machine was carried out in terms of the parameters of design, assembly and operation. Energy consumption was determined independently of the pumping systemand the irrigation machine. The total electrical energy consumption of the system was 9 039.05 kWh, for a specific consumption per cubic meters of pumped water of 0.13 kWh. From the analysis done to the irrigation schedule used, a tendency was identified for over-irrigation with advanced and insufficient irrigation activities. Likewise, the coefficient of irrigation uniformity was obtained in 78%, which favors the irregular water deposit and the need for corrective activities and therefore, the increase of energy expenditure. Costs for this type of activity accounted for 9.72% of the total production costs. [ABSTRACT FROM AUTHOR]

The goal of the present work was to determine the main properties of a compost made from bagasse, slowness and ash, obtained from the sugar factory process. To elaborate the mixture a characterization of the raw material was carried out in function of the properties related to the composting process. During the process of anaerobic biodigestion, the control of the main monitoring parameters was carried out, until reaching the maturation state. In the raw material used a bulk density of 0.12 to 0.48 g cm-3 was found, the pH oscillated between 5.2 and 8.7, while the electrical conductivity was in the range of 0,4 to 0,9 S m-1. On the other hand, the contents of P, K, Ca and Mg showed values between 0.3 and 2.8 %. Finally, a bulk density of 0.5 g cm-3 was obtained in the compost. The carbon-nitrogen (C/N) ratio, showed a linear relation with respect to the time of composting, showing a suitable maturation of the mixture. The presence of N, P, K, Ca and Mg with values of 1; 1.3; 1.1; 2 and 1.1 % were also verified. After evaluating the results it is concluded that compost shows a suitable composition to be used as organic fertilizer in agriculture. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Facultad de Ingeniería Universidad de Antioquia is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the explanation of the mechanisms that originate the failure of the soil when it is interacted for a farm tool and the prediction of efforts have been developed more than fifty analytic models, reaching the biggest acceptance those that are based on the theory of the passive pressures of the soil. For such a reason, the present work has as objective to determine the accuracy of four models that are based on the universal equation of the soil movement, during the farming of a Rhodic Ferralsol of the occident of Cuba. Was determined experimentally the resistance of the soil during the tillage under controlled conditions in the channel of soils CS-CEMA-25, and were programmed the sequences of calculation of the models Godwin & Spoor, McKyes & Ali,; Grisso et al., in the software Mathcad 15. The main results showed the limitations of these models to predict with accuracy the efforts that arise during the farming in highly cohesive soils, as well as for tools that differ of the geometry for those which originally were developed. It was also demonstrated that a high correlation (r=0.90 to 0.98) exists among the predicted values for these models, evidencing the likeness in the theoretical approaches that base them. On the other hand was observed that the speed of advance of the working tool has very little incidence in the accuracy of the predictions of the investigated models. [ABSTRACT FROM AUTHOR]