PARTICIPATORY ASSESSMENT OF THE SOIL DEGRADATION IN THE MAPIMÍ BIOSPHERE RESERVE
EVALUACIÓN PARTICIPATIVA DE LA DEGRADACIÓN DEL SUELO EN LA RESERVA DE LA BIOSFERA MAPIMÍ
/ pages 1-9
Soil degradation assessment is important to perform restoration actions, helping to identify priority areas for its attention. However, common assessment methods exclude the participation of landow¬ners, even though they are decision makers on land use and management. The aim of the current study was to generate information that supports decision making for the implementation of soil res¬toration actions. A participatory methodology was applied for the characterization of degraded areas in five livestock farms of the Mapimí Biosphere Reserve. Results show that 52 % of the 275 evaluated places have regular to priority condition. The main physical indicator of susceptibility to erosion was vegetation cover, which is being affected because of the high number of livestock located in watering places (2,802 hectares per watering place). When action research methodologies are used for social, physical and economic conditions of the protected natural area, participatory planning is workable in soil restoration affected by erosion.
POTENTIAL USE OF HUIZACHE (Acacia farnesiana L. Will) IN PHYTOREMEDIATION OF LEAD-CONTAMINATED SOILS
USO POTENCIAL DEL HUIZACHE (Acacia farnesiana L. Will) EN LA FITORREMEDIACIÓN DE SUELOS CONTAMINADOS CON PLOMO
/ pages 11-20
Several studies have been carried out in order to identify the effects of heavy metals in cultivated plants and in some species considered as hyperaccumulators. However, little efforts have been per¬formed on assessment of native species in arid areas for phytoremediation. The current study was carried out ex situ in order to evaluate lead phytoextraction rate in Acacia farnesiana L. Will. Young plants (n=48) were placed in plastic pots, in which a combination of three concentrations of lead was added (0, 250 y 500 mg•kg-1) in the form of Pb(NO3)2 and four nitrogen doses (0, 100, 300 y 500 mg•kg-1) in the form of phospho-nitrate (33-03-00). Photosynthetic rate and lead concentration in root, stem and leaf were evaluated. Nitrogen doses and lead concentrations separately didn’t provoke significant differences in photosynthetic rate of acacia plants, however, the interaction between these factors was statistically significant (P=0.0074), observing that the highest accumulation of lead was in aerial parts of the plants with a mean of 352.34 mg•kg-1.
POLYETHYLENE GLYCOL INFLUENCE ON in vitro GAS PRODUCTION PARAMETERS IN FOUR NATIVE FORAGES CONSUMED BY WHITE-TAILED DEER
INFLUENCIA DEL POLIETILÉN GLICOL SOBRE LOS PARÁMETROS DE PRODUCCIÓN DE GAS in vitro EN CUATRO FORRAJERAS NATIVAS CONSUMIDAS POR EL VENADO COLA BLANCA
/ pages 21-32
The chemical composition and the in vitro fermentation in leaves, treated with or without polyethylene glycol (PEG), of native shrub from northeastern Mexico, such as: Acacia amentacea, Celtis pallida, Forestiera angustifolia and Parkinsonia texana were established. These shrubs were gathered from fields without any disturbance. Leaves were collected at two sampling times (January and April, 2009) in three municipalities (China, Linares and Los Ramones) of the state of Nuevo Leon, Mexico. A wide range in chemical composition and in vitro gas production kinetics was observed among sites, species and sampling times of each species. A. amentacea (CT = 18 %) and P. texana (8 %), which had a higher condensed tannins content (CT), significantly increased the in vitro gas production parameters and the metabolizable energy after a treatment with PEG. Celtis pallida had the highest in vitro fermentation parameters due to the lower levels of lignin (ADL) and CT. Some variation was observed among shrubs such as in F. angustifolia that had lower fermentation and lower ADL and CT. This discrepancy could be due to genotypic characteristics relative to the type of plant secondary compounds activity. All plants resulted with high nutritional value for white-tailed deer knowing that deer have digestive mechanisms to neutralize CT.
EFFECT OF TILLAGE ON THE POROSITY OF CLAY GRASSLAND SOIL ESTIMATED BY MEANS OF AN ANALYSIS OF DIGITAL IMAGES
EFECTO DE LA LABRANZA SOBRE LA POROSIDAD DE UN SUELO ARCILLOSO DE PASTIZAL ESTIMADA MEDIANTE ANÁLISIS DE IMAGEN
/ pages 33-43
Primary tillage has been evaluated from different points of view. It is known that tillage provokes changes in soil porosity, and the processes associated with it. However, there are still questions about the size of its impact. Therefore, between 2006 and 2007 this research was carried out, focusing on the measurement and comparison of soil porosity in grassland turned into agricultural land, using an advanced imaging technique in rancho Los Angeles, Saltillo, Coahuila, Mexico (25° 6,650’ N, 100° 59,413’ O) where the climate is BWhw (x’) (e) and soils are clayey (Feozem Luvic, Hl). The effect of tillage using disk plow (LAD) and tillage using multi-plow (LM), were compared with undisturbed soil (NL). Results indicated changes in size and shape of the pores. It was observed that treatment with vertical tillage using multi-plow shows a decrease in porosity in three diameter ranges: T3 (with pores less than 2 mm2), T4 (with pores of 0.1 to 2 mm2) and T6 (with pores smaller than 0.02 mm2).
EXTREME TEMPERATURE VARIATION IN THE ‘COMARCA LAGUNERA’ AND NEARBY AREAS
LA VARIACIÓN DE LAS TEMPERATURAS EXTREMAS EN LA ‘COMARCA LAGUNERA’ Y CERCANÍAS
/ pages 45-61
Time series of daily maximum and minimum temperatures, of at least 30 years long, from 23 weather stations in the ‘Comarca Lagunera’ (Lagoon region) and nearby areas were analyzed using simple linear regression and power-spectrum density techniques for significant trends and frequencies. Time series from 15 of the 23 stations showed significant (P≤0.05) trends for both temperatures. The trend average for maximum temperature was -0.22 0C per decade, as 15 of 23 series showed downward trends, 13 significantly. The trend average for minimum temperature was -0.085 0C per decade, since 13 of 23 series showed negative trends, 11 significantly. Long-term variation was predominant becau¬se the fractal dimension averages were 1.46 and 1.47 for maximum and minimum temperature, res¬pectively. Most series showed quasi-biennial, quasi-three-year and quasi-four-year frequencies. Five stations showed 10- to 11-year frequencies for both minimum and maximum extreme temperatures;
one station showed the 20-year frequency for both temperatures.
AWASSI SHEEP PRODUCTION SYSTEMS AND REPRODUCTIVE PERFORMANCE: AN EXPERIENCE FROM THE MIDDLE EAST
SISTEMAS DE PRODUCCIÓN DE OVEJA AWASSI Y RENDIMIENTO REPRODUCTIVO: UNA EXPERIENCIA DEL MEDIO ORIENTE
/ pages 63-75
Jordan is a predominantly semi arid country. Much of the land area is uncultivable and can only be used as a range for grazing small ruminants. Fat tailed Awassi is the indigenous sheep breed of Jordan. The breed is popular for many reasons such as the adaptability to harsh ecosystems, milk production ability and having favorable meat flavor and characteristics. The sheep industry in Jordan faces many challenges, the most important of which is water shortage leading to low forage availability and high feed prices. Despite such hardships, efforts are made to improve productivity of Awassi sheep through selection, veterinary care, evaluating alternative feed sources and hormonal treatments to improve fertility and fecundity. This review highlights the major research conducted on Awassi sheep in Jordan over the last decade with special emphasis on reproductive performance.
THE PRESENCE OF ESTROGENIZED FEMALES AT THE MOMENT OF MALE EFFECT INDUCE OESTROUS ACTIVITY OF GOATS IN THE MEXICAN SEMI-DESERT
LA PRESENCIA DE HEMBRAS ESTROGENIZADAS AL MOMENTO DEL EFECTO MACHO INDUCE LA ACTIVIDAD ESTRAL DE CABRAS EN EL SEMIDESIERTO MEXICANO
/ pages 77-85
The objective of this study was to determine whether the presence of estrogenized females and sexually inactive males stimulates the estrous activity of anovulatory goats, and if the percentage of females estrogenized affects this response. Three groups (n = 31 each) of anovulatory females expo¬sed to two males/group were used. The first group was exposed to six estrogenized females (G20 %), a second group was exposed to tree estrogenized females (G10 %), and the third group was exposed to six non estrogenized females (G0 %). The total percentage of goats in estrus during the study was similar between the groups G20 and G20 % ( 93 and 90 %, respectively, P>0.05), but different in the group G0 %, where any female was in estrus (P
MENSURATION CHARACTERISTICS AND DEMARCATION OF MESQUITE (Prosopis sp) PLANTATIONS IN THE STATE OF COAHUILA
CARACTERIZACIÓN DASOMÉTRICA Y DELIMITACIÓN DE RODALES DE MEZQUITE (Prosopis sp) EN EL ESTADO DE COAHUILA
/ pages 87-96
This paper presents the forest mensuration characteristics of pure mezquite (Prosopis sp) stands in two sampling sites in the state of Coahuila, which are characterized by their importance in the production of charcoal, in order to thus determine the current tree population density and the ecological importance of the mezquite in the ecosystems of the region. This study provides the first assessment of the volume of commercial timber available in the mezquite stands, plus mapping of the distribution of mezquite in the sta¬te of Coahuila. The results show that in the state of Coahuila there are 73,868 ha covered by pure mezquite stands and 3,803,149 ha occupied by microphyll desert scrub, in which the genus Prosopis also develops. Mensuration studies were conducted in the municipalities of Viesca and San Pedro de las Colonias, re¬sulting in a population density of 867 and 567 individuals/ha, respectively, a percentage of commercial individuals of 35.23 and 27.84 % respectively and 1.64 and 39.71 m3•ha-1 of commercial timber.
XYLEM WATER POTENTIAL IN FOUR NATIVE BROWSE SPECIES FROM NORTHEASTERN MEXICO
POTENCIAL HÍDRICO XILEMÁTICO EN CUATRO ESPECIES ARBUSTIVAS NATIVAS DEL NORESTE DE MÉXICO
/ pages 97-109
Since water stress is the most limiting factor in this region, the aim of the current study was to establish how the xylem water potential (Ψ) in native shrubs such as Celtis pallida (Ulmaceae), Acacia amentacea (Leguminosae) Forestiera angustifolia (Oleaceae), and Parkinsonia texana (Leguminosae) is influenced by soil water content, air temperature, relative humidity, and rainfall. The study was carried out in an area located the municipality of China, state of Nuevo Leon. Using a Scholander pressure bomb the Ψ were estimated at 15 days intervals between January 15 and September 28, 2009 in five different plants per species at 06:00 h (predawn) and 14:00 h (midday). At the wettest period, Ψ oscillated from -0.30 (C. pallida) to -0.90 MPa (P. texana) at predawn, in contrast, at the driest period, Ψ oscillated from -2.18 (P. texana) to -3.94 MPa (F. angustifolia) at predawn. At midday, P. texana and F. angustifolia achieved the highest (-1.14 MPa) and lowest (-3.38 MPa) Ψ values, respectively. Average soil water content at depth profile 0-50cm showed between 82 and 33 % of the variation of Ψ at predawn. Soil water content at different soil depths, and relative humidity were significantly and positively correlated with Ψ at predawn; whereas air temperature and vapor pressure deficit was negatively correlated. A. amentacea and P. texana maintainedhigh values in Ψ at predawn and midday under water stress conditions, so these species may be considered as drought tolerant species.
VEGETATION ECOLOGY OF THE CHIHUAHUAN DESERT
ECOLOGÍA DE LA VEGETACIÓN DEL DESIERTO CHIHUAHUENSE
/ pages 111-130
The Chihuahuan Desert (CD), the largest in the Americas, is flanked by mountains that prevent wet winds from blowing across it; those mountain ranges are the Sierra Madre Oriental, the Trans- Mexican Volcanic Belt and the Sierra Madre Occidental in Mexico, and the Rockies in the United States. The desert covers an area of 507,000 km2, stretching from New Mexico and Texas in the United States to parts of the states of Chihuahua, Coahuila, Durango, Guanajuato, Hidalgo, Nuevo León, Querétaro, San Luis Potosi, Tamaulipas and Zacatecas in Mexico. Field work consisted of the qualitative characterization of the main vegetation types in the CH, based on their physiognomy and the collection of plant specimens for later identification. With the composition and physiognomy data, semi-realistic profiles were made of the main plant associations and the physiographic and soil conditions where they thrive. The associations detected were: Larrea tridentata microphyll scrub, Agave lechuguilla rosette scrub, Dasylirion spp. rosette scrub, grassland, chaparral, nopalera (a patch of prickly pears), mesquite, yucca, dune vegetation and halophytic vegetation.
TOWARDS A PARTICIPATORY RESEARCH APPROACH TO IMPROVE GOATS PRODUCTION SYSTEMS IN SEMI ARID MEXICO:SOCIOECONOMIC AND ECOLOGICAL
HACIA UN ENFOQUE DE INVESTIGACIÓN PARTICIPATIVA PARA MEJORAR LOS SISTEMAS DE PRODUCCIÓN DE CAPRINOS EN REGIONES SEMIÁRIDAS DE MÉXICO:UNA CARACTERIZACIÓN SOCIOECONÓMICA Y ECOLÓGICA
/ pages 131-146
The objective of this study was to identify research options which may lead to the improvement of goat productivity in a microwatershed involving two villages in the dry areas of northern Mexico. The study was carried out during 2004-2007 and was based on the systems theory. Socioeconomic and ecological aspects were evaluated at the macro-system level to identify socioeconomic differences and possible income generation options, to determine suitability of the area for goat production and to identify cropland areas to be reconverted to range production. In addition, the study assessed water erosion occurrence, evaluation of range vegetation and grazing quality changes to identify appropriate land management interventions. Poor participation of women in economic activities at the municipa¬lity level was a differentiating aspect that prompted recommendations for exploring gender-sensitive income-generation options (i.e. milk processing into highly demanded cheese). The microwatershed’s 4914 ha of land were categorized as suitable for goat production systems, however in need of impro¬vement interventions: results from water erosion and land degradation analysis identified 807 ha to be reconverted from agricultural uses to range and 208 ha from range use to native vegetation. The results concerning native vegetation availability and quality across the year defined major considera¬tions for appropriate protein and energy feeding in particular during the dry season.
THE MALE EFFECT STIMULUS INCREASES REPRODUCTIVE ACTIVITY OF MEXICAN CRIOLLO GOATS IRRESPECTIVE OF THE PHOTOPERIODIC REGIME
EL ESTÍMULO DEL MACHO CABRÍO INCREMENTA LA FUNCIÓN REPRODUCTIVA DE LAS CABRAS CRIOLLAS DEL SEMIDESIERTO MEXICANO INDEPENDIENTEMENTE DEL RÉGIMEN DE FOTOPERIODO
/ pages 147-161
Influence of a sexually-active male buck was evaluated on the onset of reproductive function (hypothalamic and ovarian activity) and estrous cycles progression in Criollo goats from the northen Mexican desert, exposed to an alternated (decreasing/increasing) artificially controlled photoperiod fluctuating within 13.4 to 10.6 light hours per day until fulfilling 6 photoperiodic cycles of 90 d each cycle: ascending (n=3); and descending (n=3). Mexican-native Criollo goats (n=30) were randomly assigned into 2 treatment groups: 1) goats exposed to a sexually-active male buck (n=15); 2) goats not exposed to a male buck (absence of a male buck; n=15). Each experimental group of goats included ovariectomized goats (OVX, n=5), ovariectomized and estradiol-implanted goats (OVX + E2, n=5), and intact-ovaries goats (Control, n=5). Blood samples were taken from OVX and OVX + E2 goats, every four weeks, during 6 h at 15 min intervals (i.e., 24 samples/day), to determine frequency (FREQ), amplitude (AMP), and concentration (CONC) of luteinizing hormone (LH). For Control goats, blood samples were taken twice every week in order to quantify serum-progesterone levels through radioimmunoanalysis (RIA). Goats implanted with E2 (OVX + E2-goats) showed an increased LH pulse frequency compared to OVX-goats without an E2 implant (2.0 ± 0.5 vs. 0.7 ± 0.1 LH pulses/ 6 h). Presence of a sexually-active male buck increased frequency, amplitude and concentration of LH in OVX goats compared to goats not exposed to males (Frequency: 3.2 ± 0.4 vs. 0.7 ± 0.1 pulses/6 h; Amplitude: 1.6 ± 0.1 vs. 0.8 ± 0.3 ng•mL-1; Concentration: 5.3 ± 0.6 vs. 2.0 ± 0.9 ng•mL-1) (P0.05). In conclusion, presence of a sexually-active male buck induced a greater ovarian activity in Criollo goats, shortening seasonal anestrous even during an ascendent controlled-photoperiod. Such strategy, using a sexually-active male buck might be helpful to increase ovarian activity and reproductive function during the seasonal anestrous of Criollo goats from dry and arid areas of northern Mexico and similar regions of the world.
FORAGE UTILIZATION AND DIET SELECTION BY GRAZING GOATS ON A SARCOCAULESCENT SCRUBLAND IN NORTHWEST MEXICO
UTILIZACIÓN DEL FORRAJE Y SELECCIÓN DE LA DIETA POR CABRAS PASTANDO EN UN MATORRAL SARCOCAULESCENTE EN EL NOROESTE DE MÉXICO
/ pages 163-171
Sarcocaulecent scrubland is representative of the Sonoran Desert of Baja California Sur, Mexico. In this area 92 % of its flora is shrubs and 23 % of these are endemic species, however, the ecological impact of animal production is unknown. The objectives of this study were to determine and to com¬pare during two years the preference and use of plant species by grazing goats. Data field collections were done from June 2006 through June 2008. Botanical composition of diet and the study area data sets were used to estimate preference and similarity indices. In the studied site total plant species were 78 and goats utilized 41 throughout the study, in each collection date goats utilized 10 to 24 species. Mean similarity index was 26 % (16 to 32 %), both preference and utilization were highly variable between collection dates for each plant species. Preference by goats was not in accordance with similarity. This pattern of feeding behavior may indicate a conservative strategy of forage utiliza¬tion by goats.
NATIVE Trichogramma (HYMENOPTERA: TRICHOGRAMMATIDAE) SPECIES COLLECTED IN AGRICULTURAL CROPS OF NORTHERN MEXICO
ESPECIES NATIVAS DE Trichogramma (HYMENOPTERA: TRICHOGRAMMATIDAE) COLECTADAS EN CULTIVOS AGRÍCOLAS DEL NORTE DE MÉXICO
/ pages 173-181
Trichogramma atopovirilia Oatman and Platner, T. deion Pinto and Oatman, T. exiguum Pinto and Platner, T. fuentesi Torre and T. pretiosum Riley, were determined from 27 samples collected in the following crops: cotton plant, sugar cane, serrano chili, cabbage, sunflower, corn, orange, walnut, soybean and tomato, established in eight states in Northern Mexico. T. pretiosum was found in cotton, serrano chili, cabbage, sunflower, corn, orange, walnut, soybean and tomato.; T. fuentesi in samples of corn and walnut; in corn samples to T. deion and T. exiguum; and T. atopovirilia in sugarcane. T. pretiosum was found in 19 of the 27 samples checked, in contrast T. atopovirilia and T. exiguum were determined in one sample each. The taxonomic determination of T. deion and T. fuentesi in samples of corn are considered as new records for Mexico.
INFLUENCE OF IRRIGATION FREQUENCY ON OREGANO (Lippia graveolens HKB) GROWTH
INFLUENCIA DE LA FRECUENCIA DEL RIEGO EN EL CRECIMIENTO DE ORÉGANO (Lippia graveolens HKB)
/ pages 183-193
Oregano (Lippia graveolens HKB) is a species native to arid areas and thus it can be an alternative crop for areas with low water availability. This study evaluated the effects of four irrigation frequencies (every 30, 45 and 60 days, and a single watering at the time of transplanting (T1, T2, T3 and T4, respectively) on growth and water use efficiency. The experimental design was randomized blocks with four replications. At 85 days after sowing in a greenhouse nursery, the seedlings were transplan¬ted and a water depth of 15 cm was applied. The response to irrigation occurred at 110 days after transplanting (dat). The highest values of leaf area index, leaf dry biomass, total plant biomass and plant growth rate were reached at the end of the study, with maximum values obtained in T1 and T2. Treatments T2 and T4 were more efficient in water use. The above results suggest that oregano plants do not require frequent watering in the early stages of growth.
APPLICATION OF A MATHEMATICAL MODEL TO PREDICT AND REDUCE WIND EROSION IN NON-PROTECTED ARID LANDS
APLICACIÓN DE UN MODELO MATEMÁTICO PARA PREDECIR Y REDUCCIÓN DE LA EROSIÓN EÓLICA EN TIERRAS ÁRIDAS NO PROTEGIDAS
/ pages 195-206
Soil wind erosion is one of the most serious land degradation problems in the arid and semi-arid regions of the world. Calculation of the potential erosion for study area averaged 70.2 Mg•ha-1•year-1. In an at¬tempt was made to reduce wind erosion using a mathematical model. Results showed that applying short predetermined succeeding lengths reduced wind erosion greatly but not fairly enough. Wind erosion tends to decrease with decreasing field distance; however the tolerable level of soil loss was not achieved by applying a short field length of 50 m and a ridge value of 0.5. The used model helps to draw some prelimi¬nary conclusions about the possible conservation practices (vegetative cover) to mitigate wind erosion. Calculations indicated that using 250 to 500 kg ha-1 of plant residues seems to be adequate to diminish soil loss to a tolerable level (~ 2 Mg•ha-1) irrespective of K and L values.
THE UNDERNOURISHMENT OF ALPINE-FRENCH GOATS DOES NOT DIMINISH REPRODUCTIVE OUTCOMES, BUT DOES AFFECT DYNAMICS OF OFFSPRING-GROWTH
LA SUBALIMENTACIÓN DE LAS CABRAS ALPINO-FRANCÉS NO DISMINUYE SUS PARÁMETROS REPRODUCTIVOS PERO SÍ LA DINÁMICA DE CRECIMIENTO DE SUS CRÍAS
/ pages 217-224
The aim of the present study was to determine whether undernourishment decreased the sexual response of Alpine-French goats, as well as to characterize both litter size and offspring-growth dy¬namics at weaning. Since April 1, 2007, a group of females (n = 10) received an experimental diet to provide 70 % of their maintenance requirements (T-70), while the other group (n = 10) received a diet to cover 100 % of their maintenance requirements (T-100). On October 1, both weight (42.4 ± 1.6 kg) and body condition (3.6 ± 0.1 units) of T-100 were higher (P0.05). Most of the females kidded in both groups (100 and 90 %, T-70 and T-100, respectively, P>0.05). However, the prolificity was higher in the T-100 compared with the T-70 group (1.8 ± 0.1 vs. 1.1 ± 0.1, respectively, P0.05). However, there was a time by group interaction (P0.05). These results suggest that, irrespective of nutritional level, reproductive outcomes of Alpine-French goats were similar. Nonetheless, both litter size and offspring growth dynamics at weaning favored the well-nourished female goats.
PARTICIPATORY EVALUATION OF GOAT TECHNOLOGIES IN SEMIARID NORTH CENTRAL MEXICO
EVALUACIÓN PARTICIPATIVA DE TECNOLOGÍAS EN CAPRINOS EN EL SEMIÁRIDO DEL NORTE CENTRO DE MÉXICO
/ pages 225-234
The goat is located in fragile ecosystems. In order to evaluate the effect of applied technologies in a participatory manner, within a framework of conservation of natural resources, on the productivity of small ruminants, six technologies were tested: 1) deferred-rotation grazing system (DRGS) achieved 60 % vegetation cover compared to 35 % for continuous grazing (CG); 996.5 vs. 280.8 kg.ha-1 of dry matter...
THE GOAT AND GOAT PRODUCTION SYSTEMS OF SMALL-SCALE PRODUCERS OF THE COMARCA LAGUNERA, IN NORTHERN MEXICO
LA CABRA Y LOS SISTEMAS DE PRODUCCIÓN CAPRINA DE LOS PEQUEÑOS PRODUCTORES DE LA COMARCA LAGUNERA, EN EL NORTE DE MÉXICO
/ pages 235-246
A baseline study was conducted in the Comarca Lagunera in the North of Mexico to evaluate the potential for implementation of a breeding program. A questionnaire was applied to 64 producers to document the production system. A phenotypic characterization of the goat population was performed; body measurements of 509 animals were recorded. The systems differentiated in production intensification, distance to urban areas and type of employees. Animal feeding is based on grazing with minimum supplementation. Body measurements including: height at withers (77.0 ± 0.3 cm), chest circumference (87.0 ± 0.3 cm) and body length (78.0 ± 0.3 cm), increased until 4 years of age. Age of first estrus, age of first service, kidding intervals, lactation length and kiddings per doe averaged, respectively, 6.9 months, 8.3 months, 1 year, 7.4 months and 6.3 kiddings. Most (40 %) producers evaluate their females on production and phenotype basis, recording is not done. The main source of males is form outside of the herd, without consideration of adaptation and productivity traits. All producers expressed that goats with high percentage of genetically improved European breeds showed adaptation problems. A community-based system, that allows access to improved animals and which considers the producers’ objectives, was considered important.
FEEDING SYSTEMS FOR GOATS AND QUALITATIVE ASSESSMENT OF FEEDSTUFFS ACCESSIBLE DURING THE DRY SEASON: TWO CASE STUDIES FROM THE MEXICAN HIGHLANDS
SISTEMAS DE ALIMENTACIÓN PARA LAS CABRAS Y EVALUACIÓN CUALITATIVA DE LOS PIENSOS A LOS QUE SE TIENEN ACCESO DURANTE LA TEMPORADA DE SECA: DOS ESTUDIOS DE CASO DEL ALTIPLANO MEXICANO
/ pages 247-258
The aim of this study was to characterize existing feeding strategies and main feed sources utilized in two different goat production systems in the Highlands of Mexico during the dry season.
Important fodder plants were collected on the rangelands and analyzed for their nutrient content. In interviews and participatory workshops farmers provided background information about their production systems. Chemical analysis of 43 fodder plants, collected during the dry season, showed mostly poor nutrient contents. Some legumes and composites had a reasonable feeding value, but may possess de¬fense mechanisms which limit their potential utilization. Improving or even maintaining the productivity of the current production systems strongly depend on the improvement of the nutritional basis, especially in the dry season when suitable fodder plants are scarce. Recent approaches such as the cultivation of certain fodder crops which also contribute to the reduction of erosion and soil loss should be conse¬quently developed and implemented. The information provided by farmers show that the two production systems studied herein differ: farmers in one study site mostly rely on traditional farming methods, while in the other site farmers continuously search for new farming options with the strong technical support of an external funded project.
HYDROGEN CYANAMIDE INCREASES PISTACHIO (Pistacia vera L.) BUD BREAK IN ARID REGIONS WITH INSUFFICIENT CHILLING
CIANAMIDA DE HIDRÓGENO INCREMENTA LA BROTACIÓN DE PISTACHE (Pistacia vera L.) EN REGIONES ÁRIDAS CON FRÍO INSUFICIENTE
/ pages 259-265
The pistachio (Pistacia vera L.) requires extended dry summers for its proper development and produc¬tivity. These conditions are characteristic of arid and semiarid areas, as are mild winters which are more constant due in part to climate change. Under these conditions chilling requirements for the optimum budbreak of this species are not met. Therefore, the use of chilling compensators is one of the ways to solve this problem. This experiment was carried out to evaluate the effects of hydrogen cyanamide on budbreak in pistachio (Pistacia vera L.) grown in an arid region with insufficient chilling hours (≤7.2 °C). Dormant buds on branches from 1 to five years old were treated on February 20 of both 2006 and 2007 with 0, 25.5 and 51.0 g.L-1 of H2CN2 [hereafter referred to as 0, 2.5 and 5.0 % (v/v) H2CN2]. Hydrogen cyanamide advanced and increased vegetative budbreak in branches from one to five years old. The hig¬hest budbreak was observed when H2CN2 was applied at 5.0 % without causing phytotoxicity. Hydrogen cyanamide applied at 5.0 % ≈ 30 days before expected budbreak can increase budbreak and substitute for chilling when pistachio is grown in environments with mild winters.
MAPPING OF THE ARIDITY INDEX AND ITS POPULATION DISTRIBUTION IN MEXICO
MAPEO DEL ÍNDICE DE ARIDEZ Y SU DISTRIBUCIÓN POBLACIONAL EN MÉXICO
/ pages 267-275
The arid and humid zones of Mexico were delimited using the Aridity Index (AI) adopted by the United Nations Environment Programme (AI = Map / Evt). Mean annual precipitation (Map) and evaporation (Ev) data were obtained from the records of 2,165 and 1,750 SMN (Mexico’s weather service) stations, respectively. Potential evapotranspiration (Evt) was calculated using the expression Evt = Ev * 0.8. Both variables (Map and Evt) were interpolated with a resolution of 90 m. Map algebra and Geographic Information System (GIS) spatial techniques were used to obtain the AI, which was classified according to UNEP classes and its population quantified. There were no significant differences between the Evt calculated and the Evt recorded at 30 CLIMWAT-FAO stations (P=0.489). It was found that hyper-arid, arid and semi-arid zones occupy 1, 27 and 35 % of the country’s total area and are inhabited by 1, 7 and 33 % of the population, respectively. The dry-subhumid, moist-subhumid and humid zones occupy 11, 16 and 15 % of the country’s landbase and are inhabited by 27, 15 and 16 5 % of Mexico’s inhabitants. This means that 63 % of the country has some level of dryness and is inhabited by 41 % of the nation’s population. is grown in environments with mild winters.