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Villanueva-Lopez G.,Colegio de Mexico | Casanova-Lugo F.,Technological Institute of La Zona Maya | Ramirez-Aviles L.,Autonomous University of Yucatan | Martinez-Zurimendi P.,Colegio de Mexico
Tropical and Subtropical Agroecosystems | Year: 2014

The aim of this study was to quantify rates of soil respiration on livestock systems with live fences (LF) formed by Gliricidia sepium trees and on livestock systems in signal grass monoculture (MP) ( Brachiaria decumbens); examine the variation of flows in the rainy and dry seasons, and fluctuations during the day, as well as soil temperature and relative humidity. Soil respiration was measured twice a month, four times a day between the hours of 00:00 to 06:00 h, 6:00 to 12:00 h, 12:00 to 18:00 h, and 18:00 to 24:00 h, in both seasons. Soil temperature and the relative humidity were simultaneously measured. The results show that the rate of soil respiration is similar between these systems, LF issued 0.97 and MP 1.01 mol CO2m2h-1. In contrast, there was influence of the time of year and time of collection of the samples. In both systems the soil flows were higher in the rainy season (1.1 mol CO2m2h-1on average) and slightly lower in the dry season (0.90 mol CO2m2h-1on average) and were higher during the night (00:00 to 06:00 hours), during the early morning hours (6:00 to 12:00 hours). Soil temperature was higher in the MP, and the relative humidity in LF. It is concluded that the main factor that caused the variation in soil respiration rates was the presence of G. sepium trees in LF, which led to lower temperatures and more stable humidity, which resulted in lower soil CO2fluxes. © 2014, Universidad Autonoma de Yucatan. All rights reserved. Source


Villanueva-Lopez G.,Colegio de Mexico | Martinez-Zurimendi P.,Colegio de Mexico | Martinez-Zurimendi P.,Sustainable Forest Management Research Institute UVa INIA | Ramirez-Aviles L.,Autonomous University of Yucatan | And 2 more authors.
Agronomy for Sustainable Development | Year: 2016

Deforestation of tropical forests for the establishment of grass monoculture for livestock production is responsible for about 30 % of CO2 emissions. This issue is particularly severe in degraded pastures because degraded soils favor CO2 flow to the soil surface. Silvopastoral systems could reduce CO2 emissions, notably by using live fences. Here, we hypothesized that live fences of Gliricidia sepium in livestock systems should reduce variations in environmental relative humidity and soil temperature and, in turn, reduce soil CO2 emissions. Here, we studied two livestock systems: (1) grass monoculture of Brachiaria decumbens with live fences of G. sepium and (2) grass monoculture of B. decumbens without live fences. We measured soil CO2 seasonal emissions at different times of the day, soil temperature, and environmental relative humidity. Nine 600-m2 plots were established in each system. All variables were measured over four 6-h period during a 24-h period, twice a month from April to September. Our results show that soil CO2 emissions showed less variability with G. septum live fences than without live fences. This lower variability is explained by the creation of a microclimate with a higher and more stable environmental relative humidity, provided by the shade of trees. Results also show, however, that global soil CO2 emissions did not differ between the two systems, with and without live fence. Moreover, soil CO2 emissions varied according to season, as shown by 1.082 g CO2 m−2 h−1 in the wet season versus 0.871 g CO2 m−2 h−1 in the dry season. Soil CO2 emissions varied also according to sampling time, as shown by 1.116 g CO 2 m−2 h−1 in the night versus 0.960 CO 2 m−2 h−1 in the morning. © 2016, INRA and Springer-Verlag France. Source


Chavarria-Aguilar L.M.,Juarez Autonomous University of Tabasco | Garcia-Herrera R.A.,Juarez Autonomous University of Tabasco | Salazar-Cuytun R.,Autonomous University of Yucatan | Chay-Canul A.J.,Juarez Autonomous University of Tabasco | And 3 more authors.
Small Ruminant Research | Year: 2016

The aim of this study was to evaluate the relationship between body mass index (BMI), body condition score (BCS), and body energy reserves in Pelibuey ewes. Twenty-four hours before slaughter, withers height (WH) and body length (BL) were measured on 28 ewes. Their BMIs were calculated as follows: BMI = (body weight (kg)/withers height (m)/body length (m))/10. The BMI and BCS showed a correlation coefficient of 0.80 (P < 0.05). The regression equation for BMI and BCS had a determination coefficient of 0.64 (RSD: 0.75). The correlation between BMI and the muscle (MUS), internal fat (IF), carcass fat and total body fat (TBF) weights ranged from 0.73 to 0.81 (P < 0.05), while the regression equations had an R2 that ranged from 0.54 for IF (RSD: 1.98 kg) to 0.60 for carcass fat (CF, RSD: 1.81 kg). BMI and body energy reserves showed a positive relationship with each other; therefore, BMI could be used as a predictor of body energy reserves in non-pregnant and non-lactating Pelibuey ewes. © 2016 Elsevier B.V. Source


Villanueva-Lopez G.,Colegio de Mexico | Martinez-Zurimendi P.,Colegio de Mexico | Martinez-Zurimendi P.,University of Valladolid | Ramirez-Aviles L.,Autonomous University of Yucatan | And 2 more authors.
Ciencia e Investigacion Agraria | Year: 2014

The aim of the current study was to evaluate the effects of two livestock systems, a livestock system with live fences (LSLF) of Gliricidia sepium associated with signal grass (Brachiaria decumbens) and a livestock system based on a grass monoculture (LSPM), on specific physical and chemical soil characteristics at different depths and distances from the fence. In each system, we randomly selected 9 plots of 600 m2. A completely randomized design was used with a 2 x 3 factorial arrangement in which we analyzed the influence of the livestock systems (LSLF and LSPM), soil strata (0-10, 10-20 and 20-30 cm) and the interaction of both factors using a multivariate analysis of variance. In addition, we performed analysis of variance to determine the effect of distance sampling in the LSLF (0-3, 3-6 and 6-9 m). The LSLFs were associated with higher (P≤0.05) soil organic matter (OM), carbon (C) and nitrogen (N) content as well as lower pH and bulk density (BD) when compared with the LSPM. In both livestock systems, the soil OM, C and N were higher (P≤0.05) in the upper (0-10 cm) strata and in the LSLF at a 3 to 6 m distance from the live fences. In the LSLF soil, the pH and BD were similar (P>0.05) at different depths and distances from the live fences. However, the soil pH varied between soil depths in the LSPM. Regarding the physical soil properties, only the sand and clay content varied (P≤0.05) at different depths in both systems but not at different distances from the LSLF. We concluded that the LSLF presents high potential to substantially improve the physical and chemical soil properties and provide an important option for reducing soil degradation in future in livestock production systems based on pasture monoculture. © 2014 Pontificia Universidad Catolica de Chile, Facultad de Agronomia e Ingenieria Forestal. All rights reserved. Source


Villanueva-Lopez G.,Colegio de Mexico | Martinez-Zurimendi P.,Colegio de Mexico | Martinez-Zurimendi P.,Sustainable Forest Management Research Institute UVa INIA | Casanova-Lugo F.,Technological Institute of La Zona Maya | And 2 more authors.
Agroforestry Systems | Year: 2015

Agroforestry systems (AFS) play a major role in the sequestration of carbon (C). The objectives of this study were to quantify the organic C stocks in the above- and below-ground tree biomass and in the soil in a cattle-farming system with live fences (CFSLF) of Gliricidia sepium and to compare the levels with those of a cattle-farming system based on a grass monoculture (CFSGM). The methodology included a forest inventory in nine randomly assigned plots and the destructive sampling of G. sepium 32 trees, measuring for each tree the diameter at breast height (DBH), stem height, total tree height, branch weight, leaf weight and coarse root weight. In addition, we measured grass biomass, collected litterfall and collected soil samples at depths of 0–10, 10–20 and 20–30 cm in the plots. A logarithmic model was developed to quantify the above- and below-ground tree biomass. The soil organic matter was determined by the dry combustion method. The total carbon stored in the CFSLF was 119.82 Mg C ha−1, with the G. sepium trees contributing 5.7 % of the total C (6.48 Mg C ha−1). The CFSGM stored 113.34 Mg C ha−1. The grass biomass stored 15.32 Mg C ha−1 year−1 in the CFSGM and 15.68 Mg C ha−1 year−1 in the CFSLF, and the litterfall in the CFSLF stored 0.205 Mg C ha−1 year−1. Despite the modest contribution of G. sepium trees to the C storage, the total carbon accumulated in the CFSLF and CFSGM was similar. © 2015 Springer Science+Business Media Dordrecht Source

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