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Abrisqueta I.,CSIC - Center of Edafology and Applied Biology of the Segura | Vera J.,CSIC - Center of Edafology and Applied Biology of the Segura | Abrisqueta J.M.,CSIC - Center of Edafology and Applied Biology of the Segura | Ruiz-Sanchez M.C.,CSIC - Center of Edafology and Applied Biology of the Segura | Tapia L.M.,Instituto Nacional Of Investigaciones Forestales Y Agropecuarias Inifap
Acta Horticulturae | Year: 2011

The use of soil water sensors for irrigation management requires soil water content to be maintained within two limits: the upper limit at field capacity and the lower limit being slightly above the point where a crop begins to experience water stress. The objective of this work was to evaluate whether changes in the daily reduction of the soil water content could be used to identify the beginning of plant water stress. For that purpose, an experiment was carried out in a drip irrigated mature peach tree orchard (Prunus persica (L.) Batsch, 'Flordastar', on GF-677 rootstock) at the CEBAS-CSIC experimental field station, in Santomera, Murcia (Spain). One drying cycle was applied to trees (stress treatment) for one month, coinciding with the post-harvest stage. The soil water content (SWC) was measured continuously using multisensor capacitance probes at 0.8 m soil upper layer and three SWC-derived indices were calculated. The beginning of plant water stress was identified by the first statistically significant difference in midday stem water potential (Ψ stem) between stressed and well watered trees. The 'breaking point', calculated as the transition between a relatively rapid rate to a slower rate of reduction of SWC in the drying soil, coincided with the beginning of plant water stress as judged from the Ψ stem reduction. The dates for both the indication of plant water stress using the SWC-derived indices delayed two days respect to that of Ψ stem reduction or breaking point. The results suggested that lower SWC limit for irrigation management in peach trees using the capacitance probes could be established as 10% of the soil field capacity during the postharvest period. Source


Abrisqueta I.,CSIC - Center of Edafology and Applied Biology of the Segura | Vera J.,CSIC - Center of Edafology and Applied Biology of the Segura | Conejero W.,CSIC - Center of Edafology and Applied Biology of the Segura | Abrisqueta J.M.,CSIC - Center of Edafology and Applied Biology of the Segura | And 2 more authors.
Acta Horticulturae | Year: 2011

The water balance of drip-irrigated peach trees (Prunus persica (L.) Batsch 'Flordastar' on GF-677 peach rootstock) planted in drainage lysimeters (5×5×1.5 m) with a clay loam textured soil located in southern Spain was determined during a 24-month period. Trees were drip irrigated during the night using one lateral pipe per tree row and eight emitters per tree, each delivering 2 L h -1. Tree irrigation requirements were determined according to daily reference crop evapotranspiration (ET o) by the Penman-Monteith equation, a crop factor based on the time of the year and the percent of ground area shaded by tree canopy. The water balance parameters are shown and discussed. The measured crop water use followed the same trend as the ET o, increasing with time, but reaching a peak in August, a shift of 1.5 months compared with the peak in ET o. The crop coefficient (K c) was calculated using the measured crop water use and the ET o values. Over the two years, K c increased gradually, beginning with irrigation in February and extending to early May. There was a brief fall at the end May in K c, followed by a recovery in early June until a maximum K c was reached in August. This was followed by a rapid decline in K c in mid November, when irrigation ended. The crop coefficients calculated on the basis of a water balance would have saved up to 33 and 17% for 2007 and 2008, respectively, in irrigation water compared to the FAO-56 recommendations. Source


Moreno-Sanchez R.,University of Colorado at Denver | Torres-Rojo J.M.,Research Center y Docencia Economicas | Moreno-Sanchez F.,Instituto Nacional Of Investigaciones Forestales Y Agropecuarias Inifap | Hawkins S.,University of Colorado at Denver | And 2 more authors.
Journal of Forestry Research | Year: 2012

Forest managers and policy makers increasingly demand to have access to estimates of forest fragmentation, human accessibility to forest areas and levels of anthropogenic pressure on the remaining forests to integrate them into monitoring systems, management and conservation plans. Forest fragmentation is defined as the breaking up of a forest unit, where the number of patches and the amount of expose edge increase while the amount of core area decreases. Forest fragmentation studies in Mexico have been limited to local or regional levels and have concentrated only on specific forest types. This paper presents an assessment of the fragmentation of all forest types at the national level, their effective proximity to anthropogenic influences, and the development of an indicator of anthropogenic pressure on the forests areas. Broadleaf forests, tropical evergreen forests and tropical dry deciduous forests show the greatest fragmentation. Almost half (47%) of the tropical forests are in close effective proximity to anthropogenic influences and only 12% of their area can be considered isolated from anthropogenic influences. The values for the temperate forests are 23% and 29% respectively. Anthropogenic pressure in the immediate vicinity of anthropogenic activities is much higher in the tropical forests (75 in a scale 0-100) than in the temperate forests (30). When considering these results jointly, the tropical forests, and more specifically, the tropical evergreen forests and tropical dry deciduous forests are under the greatest pressure and risks of degradation. © 2012 Northeast Forestry University and Springer-Verlag Berlin Heidelberg. Source


de los Santos-Villalobos S.,Research Center Estudios Avanzados Ipn | Barrera-Galicia G.C.,Research Center Estudios Avanzados Ipn | Miranda-Salcedo M.A.,Instituto Nacional Of Investigaciones Forestales Y Agropecuarias Inifap | Pena-Cabriales J.J.,Research Center Estudios Avanzados Ipn
World Journal of Microbiology and Biotechnology | Year: 2012

Colletotrichumgloeosporioides is the causal agent of anthracnose in mango. Burkholderiacepacia XXVI, isolated from mango rhizosphere and identified by 16S rDNA sequencing as a member of B. cepacia complex, was more effective than 6 other mango rhizosphere bacteria in inhibiting the model mango pathogen, C. gloeosporioides ATCC MYA 456. Biocontrol of this pathogen was demonstrated on Petri-dishes containing PDA by > 90 % reduction of surface colonization. The nature of the biocontrol metabolite(s) was characterized via a variety of tests. The inhibition was almost exclusively due to production of agar-diffusible, not volatile, metabolite(s). The diffusible metabolite(s) underwent thermal degradation at 70 and 121 °C (1 atm). Tests for indole acetic acid production and lytic enzyme activities (cellulase, glucanase and chitinase) by B. cepacia XXVI were negative, indicating that these metabolites were not involved in the biocontrol effect. Based on halo formation and growth inhibition of the pathogen on the diagnostic medium, CAS-agar, as well as colorimetric tests we surmised that strain XXVI produced a hydroxamate siderophore involved in the biocontrol effect observed. The minimal inhibitory concentration test showed that 0. 64 μg ml-1 of siderophore (Deferoxamine mesylate salt-equivalent) was sufficient to achieve 91. 1 % inhibition of the pathogen growth on Petri-dishes containing PDA. The biocontrol capacity against C. gloeosporioides ATCC MYA 456 correlated directly with the siderophore production by B. cepacia XXVI: the highest concentration of siderophore production in PDB on day 7, 1. 7 μg ml-1 (Deferoxamine mesylate salt-equivalent), promoted a pathogen growth inhibition of 94. 9 %. The growth of 5 additional strains of C. gloeosporioides (isolated from mango "Ataulfo" orchards located in the municipality of Chahuites, State of Oaxaca in Mexico) was also inhibited when confronted with B. cepacia XXVI. Results indicate that B. cepacia XXVI or its siderophore have the potential to be used as a biological control agent against C. gloeosporioides; thus diminishing environmental problems caused by the current practices to control this disease. © 2012 Springer Science+Business Media B.V. Source


Roth D.,University of Colorado at Denver | Moreno-Sanchez R.,University of Colorado at Denver | Torres-Rojo J.M.,Research Center y Docencia Economicas | Moreno-Sanchez F.,Instituto Nacional Of Investigaciones Forestales Y Agropecuarias Inifap
Applied Geography | Year: 2016

Land use/cover types have an associated level of human induced disturbance of the environment. Previous studies in Mexico document the extent of land use/cover types and their changes over time. This information is important but not sufficient to support land use planning and environmental conservation decisions. This article explores the informational value of generating a numerical quantification of the level of human induced disturbance of the environment associated with land use/cover classes and their patterns at the national and state levels in Mexico. Estimates for land use/cover patterns existing in 2002, 2008 and 2013 are created. A disturbance scale created in a previous study was adapted and calibrated for 14 broad land use/cover types through domain expert opinions. The results indicate that the disturbance of the environment is increasing at the national level, but at a significantly slower rate between 2002 and 2008 (1.9%) and 2008-2013 (0.8%). Six states report a decrease in total environmental disturbance. A land use/cover transition analysis conducted for these states indicates a large proportion of transitions from anthropogenic land use/covers to natural ones. © 2015 Elsevier Ltd. Source

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