Euriel Millan-Romero ¹, Andres Mass-Cruz ¹, Yerye Chajin-Salcedo ¹, Carlos Millan-Paramo ¹

Affiliations
1 University of Sucre, Cra. 28 # 5-267, Sincelejo, CO

Abstract

Objectives: To investigate how the time of day affects the water potential values of the purple elephant grass (Pennisetum purpureum) in areas with and without irrigation during the dry season and the relation with soil moisture, in order to establish a good performance of the crop. Method: Water potential was measured with the Scholander pressure chamber and humidity was measured with a Moisture Soil Kit. Four demonstration plots of 3 m × 3 m (three with irrigation and one without irrigation) were select and the determination was made at: 08:00, 13:00 and 17:00, for 10 weeks two days a week. Findings: The crop under irrigation maintained values of water potential between 0.02 to 0.05 MPa, and crop without irrigation between 0.02 and 0.25 MPa. Additionally, a higher yield was obtained for the irrigated crop of 22 t/ha/year in dry matter. The purple elephant grass maintains a good yield with humidity between 20% and 30% and water potential between 0.03 and 0.05 MPa. Novelty /Improvement: Obtaining the equation (Y = 0.493 * X^{- 0.775}) that relates soil moisture and leaf water potential of purple elephant grass Pennisetum purpureum Schumach. (Poaceae), which can be used to find the water potential (Y) in a soil with a sandy clay loam texture.

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Euriel Millan-Romero ¹, Ismael Sandoval-Assia ¹, Carlos Millan-Paramo ¹

Affiliations
1 University of Sucre, Sincelejo, CO

Abstract

Objectives: To determine the evapotranspiration and crop coefficient of creole cucumber under a drip irrigation system in Corozal (Department of Sucre, Colombia). Methods: The water requirement was determined using the gravimetric method; evapotranspiration was determined by water balance equation and climate record (evaporimeter); the crop coefficient (Kc) was calculated with the equation that relates crop Evapotranspiration (ETc) and reference Evapotranspiration (ETo). The experimental layout of the study was a split-plot design with 2 treatments and 3 replications. Treatment 1 (T1) consisted in the application of daily irrigation and Treatment 2 (T2) in the application of a sheet accumulated every three days. Findings: The evapotranspiration by water balance were 3.17 (T1) and 2.93 mm/day (T2); and by climate record was 2.14 mm/day. The crop coefficient for water balance was 0.89 and 0.87, respectively in each treatment. The total water applied was 78.52 l/plant for each treatment; the average yields were 20.26 and 20.24 t/ha for treatments 1 and 2 respectively. Application: The evapotranspiration and crop yield did not show significant differences between the irrigation treatments. The technology of drip irrigation allowed a frequent application of small amounts of water that approach the rate of absorption of water by the crop, becoming an effective option to improve the nutritional regimen and life of the region.

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Euriel Millan-Romero ¹, Luis Salcedo-Martínez ¹, Carlos Millan-Paramo ¹

Affiliations
1 University of Sucre, Sincelejo, CO

Abstract

Objectives: To determine the annual rate of Soil Respiration (SR) in different vegetation uses in the University of Sucre, analyzing its relationship with temperature, soil moisture and some properties of soils. Methods/Analysis: It includes the selection of the sampled areas, the location of the plots and the measurement of the SR, temperature and soil moisture in each one over a year. The determination of some properties of soils and the use of statistical software that allows comparing data between each of the soils and determining the existence of relationship between the measured variables. Findings: The organic matter in the soil turned out to be the main limiting factor of the SR, greater amount of organic matter favors the SR. The SR was not related to the soil temperature but to the soil moisture where ranges were formed that optimizes or limits the SR. The area with the greatest diversity of plant species (native vegetation) had the highest SR average (46.42 μmol CO₂/m²s), followed by Hura crepitans (42.04 μmol CO₂/m²s), Pasture (41.66 μmol CO₂/m²s) and Tectona grandis (40.65 μmol CO₂/m²s), these differences were due to the characteristics of each soil and the sun exposure of each one. Novelty/Improvement: The accumulated Soil Respiration ASR resulted to have a direct linear relationship with respect to time. Based on this, the annual SR rate was estimated between 49.3 and 49.4 mol CO₂/m² in the area with native vegetation, 47.5 and 47.6 mol CO₂/m² in H. crepitans, 44.8 and 44.9 mol CO₂/m² in pasture and 44.3 and 44.4 mol CO₂/m² in T. grandis.

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Carlos Millan-Paramo ¹, Euriel Millan-Romero ¹

Affiliations
1 Universidad de Sucre, Sincelejo, Sucre, CO

Abstract

Objectives: To use MSAA metaheuristics recently developed, in the optimization of Shell and Tube Heat Exchanger and compare the results obtained with those reported by other approaches. Methods/Analysis: MSAA was recently introduced for solving global optimization problems and is a newly improved version of the Simulated Annealing (SA). Two case studies reported in the literature were analyzed to evaluate the performance of MSAA. Findings: In the two cases studied, the MSAA obtained better results than those obtained by other metaheuristic algorithms, giving validity to the work reported here. Novelty/Improvement: Development of a new approach to design of Shell and Tube Heat Exchanger, where MSAA is used as optimizer.

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