Abstract—The present work analyzes the sources of supply and regulation of ecosystem services (ES) in the Tiltepec watershed, Oaxaca, Mexico, specifically the production of fuelwood, water for human consumption, forage for domestic livestock, as well as regulation for runoff and sediments estimated with the MUSLE model (Modified Universal Soil Loss Equation), Random sampling points were defined according to the soil used and coverage, to determine production of fuelwood and forage. Firewood was evaluated in quadrants of 10 x 10 m for tree strata and 5 x 5 m for shrub strata. Forage production was determined with lines of 20 m and quadrants of 0.25 x 0.25 m to determine biomass and vegetation cover. Water supply was estimated with inflows from springs and the storage capacity of infrastructure works and water demand estimated with the current population and the maximum daily and hourly consumption. The estimated average fuelwood consumption was 1.4 kg person-1 day-1for a total volume of 3,189.5 m3. The estimated average forage yield was 856.6 kg ha-1 and a grazing coefficient of 13.9 ha animal unit (AU-1), with a census of 171.7 AU. The springs produce a daily volume of 150.4 m3 and the storage water capacity is 184.7 m3 for human consumption and 718.5 m3 for irrigation and recreational uses. With the MUSLE model, a reduction in runoff of 33.93% and 62.93% in specific degradation was estimated comparing the current scenario with that of 1984. The presence of ES in the Tiltepec watershed is essential to provide well-being to local people and regulation of erosion process through works, soil and water conservation practices. These will enable better provision of goods and services.
Keywords— provision and regulation services, water, forage, firewood and sediments.
Germination Capacity in Culture Medium of Prosopis Laevigata Seeds in the Presence of Copper Sulphate
Abstract—Copper is a heavy metal that has been used as an anti-fungal agent in various crops, this is why it accumulates in certain agricultural lands at levels that become toxic to plants, as well as to microflora. Cooper, although essential to plants, is toxic when found in high concentrations. The objective of this study was to determine if this element is capable of stimulating and at the same time inhibiting germination of seeds of Prosopislaevigata (mesquite) depending on concentration of CuS04.5H20 solutions. A completely randomized experimental design with seven treatments and three repetitions was used to determine tolerance of mesquite seeds to copper. The variables evaluated were percentage of daily germination (PDG-A, PDG-B, and PDG-C), accumulative germination (AG-A, AG-B, and AG-C), average germination time (AGT), germination rate (GR) and anhydrous weight (AW) of mesquite seeds. The culture media supplied with concentration of 10-4 M of copper sulfate (CuS04.5H20), corresponding to treatment four (T4) showed significant differences (p≤0.05) in variable percentage of daily germination at 48 hours (PDG-B), which presented a germination of 66.7% in relation to treatment two (T2) with a concentration of 10-2 M of CuS04.5H20 and germination of 22.2%. Results obtained after 72 hours for percentage daily germination variable (PDG-C) with>p<0.1 showed that mesquite is a species that can tolerate and adapt in germination stage for culture medium with concentrations from 10-2 to 10-7M of CuS04.5H20, and consequently use of seedlings for phytoremediation of sites contaminated with copper.
Keywords— heavy metal, pesticide, germination percentage, average germination time, and culture medium.
Abstract— Water availability and quality are important factors that determine not only where people can live, but also the quality of life. The Mukungwa river is affected by rainy season especially at Ngaru point before discharge in Nyabarongo river, where its physico – chemical properties are seasonally changed. This may cause serious problems on all forms of life in the river. Objective of this work was to assess the impacts of rainy season on physico-chemical properties of Mukugwa River before discharging into Nyabarongo River at Ngaru. The parameters such as pH, temperature, turbidity, electric conductivity, total dissolved solids (TSS), phosphates, nitrates, and ammonium were monitored in three rainy seasons: April, 2012; October, 2012 and May, 2017 respectively. In this research, pH, temperature, electric conductivity were analyzed in situ using multifunction pH-meter and others parameters, were analyzed in laboratory using electrometric, volumetric, turbidity tube and colorimetric methods. The measured values for each parameter in three seasons were analyzed using MS Excel, and then compared to their international standards for surface water delivered by World Health Organization (WHO). The findings showed high variation of TSS (134mg/l, 178mg/l, and 582mg/l), turbidity (322NTU, 317NTU and 1560NTU) and ammonium (0.498mg/L, 0.536mg/L and 0.78mg/L) in three rainy seasons assessed. The quality of Mukungwa River needs prevention measures in order to control its pollution by erosion.
Keywords— physico-chemical parameters, seasonal analysis, water quality, water pollution.