REVISTA TERRA LATINOAMERICANA <h4><span style="float: right; color: #111111; font-family: 'helvetica neue',helvetica,arial,verdana,sans-serif; font-size: 14.4px; font-style: normal; font-variant: normal; letter-spacing: normal; line-height: 18.72px; text-align: justify; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; display: inline ! important; background-color: #ffffff;">ISSN Electrónico 2395 - 8030.</span></h4> The Mexican Society of Soil Science en-US REVISTA TERRA LATINOAMERICANA 2395-8030 Portada Interna 39 Rosa Maria López-Atilano Copyright (c) 2021-01-18 2021-01-18 39 Editorial Committee 39 Rosa Maria López-Atilano Copyright (c) 2021-01-18 2021-01-18 39 Index 39 Rosa Maria López-Atilano Copyright (c) 2021-01-18 2021-01-18 39 Actinobacteria from avocado rhizosphere: antagonistic activity against Colletotrichum gloeosporioides and Xanthomonas sp. <p>Actinobacteria from the rhizosphere of agricultural crops are a potential source of antagonists against phytopathogenic microorganisms. Thus, the objective of this study was to characterize the antagonistic activity in vitro of actinobacteria from the rhizosphere of avocado trees (Persea americana) against Colletotrichum gloeosporioides and Xanthomonas sp. Actinobacteria were isolated from rhizosphere soil samples of avocado trees var. Hass collected from an orchard from Ziracuaretiro, Michoacán. The isolated strains were assessed against C. gloeosporioides and Xanthomonas sp. by means of in vitro confrontation tests. The antagonistic activity was determined by measuring the radius and diameter of the growth inhibition zone of C.&nbsp;gloeosporioides and Xanthomonas sp., respectively. A total of 41 actinobacterial strains were isolated, of which 44% inhibited growth of at least one of the two plant pathogens. Specif ically, 15% of the isolates inhibited growth of C. gloeosporioides, 22% of Xanthomonas sp. and 7% of both phytopathogens. The mycelial growth inhibition radius of C. gloeosporioides fluctuated from 6.6 to 15.5&nbsp;mm, while in Xanthomonas&nbsp;sp., the inhibition zone was from 15.5 to 62.7 mm. These results indicated the importance of rhizosphere actinobacteria as antagonists of phytopathogenic microorganisms, some of which could be used as potential biological control agents against anthracnose and bacterial leaf spot.</p> Jesús Rafael Trinidad-Cruz Gabriel Rincón-Enríquez Zahaed Evangelista-Martínez Cecilia Guízar-González Jhony Navat Enríquez-Vara Luis López-Pérez Evangelina Esmeralda Quiñones-Aguilar Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-18 2021-01-18 39 10.28940/terra.v39i0.802 Tolerance to heavy metals of plants from arid zones <p>In Mexico, arid areas represent more than half of the territory where erosion is due to pollution, so the level of tolerance of representative plant species should be studied to restore or reforest. This study evaluated six species from arid zones – Agave funkiana, A. obscura, A. salmiana of the Asparagaceae family and Opuntia cochenillifera, O. ficus-indica, Pereskia sacharosa of the Cactaceae family. The plants were propagated in vitro to obtain shoots that were established at different cadmium (Cd2+) and lead (Pb2+) concentrations during the rooting stage to determine their tolerance. The Probit Analysis was used to calculate the mean lethal concentration (LC50) at the different doses, which produced different effects in the six species of arid zone plants evaluated in this investigation. The species A. salmiana and P. sacharosa obtained a mortality of 55% with 0.009 mM of Cd and 77% with 0.8 mM for Pb. These concentrations were the highest. Thus, ecotoxicological bioassays are useful for evaluating contaminants, such as heavy metals in tolerant plants as A. obscura, O. cochenillifera, and O. ficus-indica.</p> Lucila Perales-Aguilar José Antonio Esquivel-Rivera Héctor Silos-Espino José Cruz Carrillo-Rodríguez Catarino Perales-Segovia Copyright (c) 2021 Terra Latinoamericana 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.759 Agronomic response of two tomato varieties (Solanum lycopersicum L.) to the application of the biostimulant whit chitosan <p>Chitosan has properties that promote growth and nutrition of crops. It is a biostimulant that in previous studies it demonstrated activity as growth regulator, germination and vigor promoter of plants, and yield increaser. In this work, it was evaluated the individual or combined effect of the application of chitosan by seed imbibition and foliar administration at the beginning of flowering on the agronomic response (growth, development and yield) of two varieties ESEN and L-43, established in f ield conditions with a block design at random with three replicates. The results show that the combined treatment of chitosan on the seeds in doses of 1 g L-1 and at the beginning of flowering in doses of 300&nbsp;mg ha-1 promotes the evaluated variables associated with yield, and increasing this up to 60.9&nbsp;Mg&nbsp;ha-1 in the ESEN variety and up to 27 Mg&nbsp;ha-1 in the L-43 variety, which represents an increment of 28.5 and 25% respectively, in comparison with the control treatment. It is concluded that the biostimulant chitosan applied as combined treatment during seed imbibition and foliar via at the beginning of flowering has signif icant results improving the variable number of flowers for plants, number of fruits, mass of the fruits and yield for both varieties in comparison with the treatment control, being obtained yield among 47‑60.9&nbsp;Mg ha-1 when applying chitosan for single 42‑43 Mg ha-1 in the treatment control.</p> Tomás Rivas-García Luis Gustavo Gonzalez-Gomez Tony Boicet-Fabré María Caridad Jiménez-Arteaga Alejandro Bernardo Falcón-Rodríguez Julio César Terrero-Soler Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.796 Land use change model in Carmen-Pajonal-Machona lagoon system, Mexico <p>Change in land use is a dominant process with negative effects on the structure and functioning of ecosystems. The coastal area of Tabasco is very important for economic development because of the large coastal wetland areas that flow into the Gulf of Mexico. However, coastal wetlands are strongly altered by the change in land use due to their proximity to urban areas, oil extraction and agricultural activities. They are also severely threatened by climate change and sea level rise. This study analyzed the change in land use in Carmen-Pajonal-Machona lagoon system on Tabasco coast through Land Change Modeler during 2000-2015. A probabilistic-spatial scenario was generated in 2030 through Markov Chains and Cellular Automata, detecting that secondary vegetation, wetlands, and acahuales altogether decreased 14 238&nbsp;hectares from 2000-2015. These changes have affected the reduction of coastal habitats and lead to high flood risks for the population in this area. Additionally the 2030 projection shows alarming values because the ecosystems reflect a loss of 8090 hectares if no change in favor is performed in the paradigm of coastal soil management. Therefore, future trends in land use change on the coast of Tabasco can be mitigated through the implementation of sustainable development policies that involve short- and medium-term planning of the establishment of Territorial Planning programs and the creation of Protected Natural Areas.</p> Rodimiro Ramos-Reyes Miguel Ángel Palomeque-De la Cruz Hector Javier Megia-Vera Daniel Pascual-Landeros Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.587 Impact of climate change on potential evapotranspiration and growing season in Mexico <p>Potential evapotranspiration (PET) and length of growth period (LGP) are essential indicators of agricultural planning. National and local agendas should consider climate change scenarios and its impact on evapotranspiration. Therefore, the objective of this study was to analyze spatial distribution of PET and LGP in current climate conditions throughout the country, and under a climate change scenario to have suff icient technical elements for recommending adaptation actions for agricultural national production. The monthly PET was estimated from the reference PET (ET0) by the Penman-Monteith method using parameter and monthly average rainfall (R), start and end date, and length of growing period were evaluated. Once this was done, 28 climate change scenarios were studied to def ine the alteration of PET and its effect on LGP in the agricultural areas of the country. PET is expected to increase practically throughout the national territory as a consequence of the general increase in temperature and the decrease in relative humidity. PET classes smaller than 1000 mm per year may decrease, while those greater than 1000 mm may increase on average 20% around the years 2040-2069, and almost 50% towards 2070-2099. When climate change in LGP was considered for each state, three of them (Baja California Sur, Coahuila, and San Luís Potosí) were considered to experience no change concerning current conditions. In the rest of states, the LGP may decrease due to a combination of changes at the beginning and end of the growing period. Cartographic studies allow spatial analysis of the results, which should be integrated into the planning of agricultural water use. At the same time, they make it possible to advance in the design of measures to adapt for climate change with a solid technical support.</p> Alejandro Ismael Monterroso-Rivas Jesús David Gómez-Díaz Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.774 In vitro establishment of the nematophagous fungus Pochonia chlamydosporia var. catenulata in different soils <p>The edaphic conditions present in agroecosystems can influence the establishment and effectiveness of a microbial control agent for nematodes. For this reason, the objective of the present investigation was proposed to evaluate the in vitro establishment of Pochonia chlamydosporia var. catenulata in Cuban agricultural soils of the Ferralitic, Fluvisol and Brown type. For this, three types of soils were analyzed using the soil membrane technique, evaluating in each one of them the native microbial populations, the mycelial growth and the relative growth of the nematopophagous fungus of interest. A completely randomized design was used and the statistical processing of the data obtained was performed using a factorial ANOVA and linear regression. The results showed that P. chlamydosporia var. catenulata grew and produced chlamydospores in all the edaphic conditions evaluated, however, the greatest growth was registered in Fluvisol and Ferralitic soils compared to Pardo. This suggested that the higher native microbial populations and the acid pH present in the Brown soil, could affect the growth of this fungus. The results obtained conf irm that the nematophagous fungal species P. chlamydosporia var. catenulata has adaptability, persistence and multiplication capacity in different soils and its use is suggested in Fluvisol, Ferralitic and Brown soils, provided they do not present an acid pH ≤ 4.17.</p> Wilson Geobel Ceiro-Catasus Maité Hidalgo-Viltres Leopoldo Hidalgo-Díaz Jersys Arévalo-Ortega Milagro García-Bernal José Manuel Mazón-Suástegui Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.792 Soil quality evaluation: generation and interpretation of indicators <p>Soil management practices alter its properties, especially when the energy inputs to the soil-plant system are less than the outputs, or its resilience is unable to return it to the state prior to the intervention. When the disturbances approach the tolerance limits of the soil system, factors that limit production appear. Changes can be established using quality indicators and indices. These show the direction of change over time. The objective of this work was to evaluate the current soil quality in four agricultural ejidos of Tepeaca, Puebla, Mexico, which have centuries of dedication to agricultural production. The history, the most common cropping patterns and the dominant land classes, defined with the participation of local producers, were investigated. Physical, chemical and biological properties of soils subjected to different management were analyzed and quality indicators were defined. The&nbsp;selection criteria for the sampling sites were the most frequent cultivation patterns as follows: (i) cut flower, (ii) continuous vegetables, and (iii) vegetables with resting period during the season with no rain. The same soils were used without management as reference. The properties selected as indicators were the following: pH, electrical conductivity, soil organic matter, wet aggregate stability, Olsen extractable phosphorus, DTPA extractable iron, and earthworm density. The first four were sensitive to differentiate between undisturbed (uncultivated) soils from cultivated soils. The last four were selected by showing rates of change according to cropping patterns, which indicates the need to promote agronomic management strategies. With these properties, a soil quality index was built that allows to establish the direction of change that soil quality will experience when modifying one or more indicators.</p> Ximena Castillo-Valdez Jorge Dionisio Etchevers-Barra Claudia María Isabel Hidalgo-Moreno Arturo Aguirre-Gómez Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.698 Evaluation of the yield, morphological and chemicals characteristics of varieties of purple corn (Zea mays L.) in the region Cajamarca-Peru <p>Peru has a great diversity of agricultural products due to the variety of climates and geographical diversity, hence it accounts with seven main races of purple corn. Therefore, the objective of our research was to evaluate the yield, and the morphological and chemical characteristics of five varieties of purple corn, which were the following: INIA-601, MMM improved purple corn (experimental variety), UNC‑47, INIA‑615, and PM-581, plus Canteño race, which was used as control. The study was conducted at two altitudinal levels, 2770 m (Llollon) and 3140 m (Llanupacha), both belonging to the District of Ichocan, Province of San Marcos and Region Cajamarca in Peru, during 2017/18 and 2018/19 agricultural campaigns. The agronomic variables and anthocyanin content were evaluated. The results show that the best yield on average was for INIA-601, with 5.3 Mg ha-1 in Llanupacha and with 4.5 Mg ha-1 in Llollon. The varieties with the highest height of the plant and ear were MMM (2.33 and 1.2&nbsp;m) and INIA-601 (2.35 and 1.25 m) in Llollon; whereas in Llanupacha, MMM (1.93 and 0.88 m) and INIA-601 (1.9 and 0.88 m), respectively, obtained the highest values. The INIA-615 variety showed the earliest flowering for females and males in both altitudinal levels, at days101.5 and 93.3 in Llollon and at days 125.6 and 118.3 in Llanupacha, respectively. In addition, this variety obtained the lowest percentage of rot in Llanupacha (2.3%) and in Llollon (5.9%). In addition, the INIA-601 variety was highlighted for having the highest quantity of anthocyanins in both the ear and bracts, presenting (6.7 and 7.5 mg g-1) and (2.9 and 2.5 mg g-1), in Llanupacha and Llollon, respectively.</p> Melissa Rabanal-Atalaya Alicia Medina-Hoyos Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.829 Nitrous oxide (N2O) measurements in managed soil under grazing with dairy cattle <p>Nitrous oxide (N2O) emissions measurements in livestock systems in the Dominican Republic are a priority for its government. The N2O has been responsible for 5% of total GHG (greenhouse gas) in the last 100 years. In Dominican livestock, various nitrogen fertilizers and amendments are used to increase the productivity these systems. However, if these fertilizers are not properly managed, these could generate N2O emissions. Therefore, our research was carried out with the aim of quantifying N2O emissions from grazing forage with dairy cattle. A Bermuda grass pasture (Cynodon dactylon) from Casa de Alto, Dominican Republic was used. The study was conducted during the period of June – August, 2018. A completely randomized sub-divided plot design was used with three factors, four repetitions and three treatments (urine, urea, and control). Closed-flow PVC chambers were used to obtain gas samples and determine N2O emissions. In addition, climatic factors, nitrogen (N) in urine, soil and grass were recorded. Data were analyzed with the InfoStat statistical software. The N2O emissions averaged the following values: 0.56 mg L-1 for control, 1.02 mg L-1 for urine and 1.18 mg L-1 for urea. The only treatment that showed statistical differences with the control (P&nbsp;&lt;&nbsp;0.05) was urea. Emissions were 5.6, 10.2 and 11.8&nbsp;kg ha-1 for the control, urine and urea, respectively, with high emissions compared to results obtained in other research in the country.</p> Pedro Antonio Núñez-Ramos Gregorio García-Lagombra Joaquín Caridad del Rosario Víctor José Asencio-Cuello Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.813 Analysis of anthocyanins in the purple corn (Zea mays L.) from Peru and its antioxidant properties <p>The purple corn (Zea mays L.), is an important cereal in Peru, which contains polyphenols, among which include flavonoids, being anthocyanins the most important one. The ear (cob and grain) is made up of 85% grain and 15% cob. Its high content of anthocyanin, mainly as cyanidine-3-glucoside (C3G), makes it act as a powerful natural antioxidant, anti-carcinogenic, and anti-inflammatory, it also helps lower blood pressure and high cholesterol, improves blood circulation and promotes tissue regeneration. Because of these important benefits, it arises the need to understand the mechanism of action of anthocyanins in human health. Therefore, the objective of the present review paper is to describe the chemical structure of anthocyanins, what types and factors affect not only its color but also its stability. In the second part, it was detailed the different races and varieties improved of purple corn in Peru, and the amount of anthocyanins found with the different chemical techniques used. Finally, the different biological activities of anthocyanins are described with emphasis in the most important one as a powerful antioxidant. Finding that the optimal extraction conditions of anthocyanins are with 1 g of sample and 15 mL of water with in agitation constant for 15 min at 90 ºC, highlighting the high antioxidant power in both systems in-vitro and ex-vivo.</p> Melissa Rabanal-Atalaya Alicia Medina-Hoyos Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.808 The h index: overvaluation of its use in the assessment of the impact of scientific work in Mexico <p>To judge the impact and relevance of the results of the scientif ic work, the researchers are subjected to evaluation processes that involve records of publications and the corresponding citations. For this purpose, some index has been developed. Among them, the index proposed by Hirsch are considered in most evaluation processes. The analysis developed here concludes that the h-index does not measure the relative contribution of a researcher in publications, especially in those that are generated by groups of between 80 and 700 authors. Likewise, the aforementioned index does not consider book publications, nor the contribution of a researcher in the formation of human resources, nor the formation of scientif ic groups or societies. Nor does the h index value contributions in technological innovation, in the dissemination of scientif ic knowledge. In a relevant way, it must be emphasized that the h index does not take into account the contribution of a specif ic researcher to the establishment of public policies generated through scientif ic research, which can be strategic and of local, regional and even national relevance. Assessing the work of a researcher based primarily on its h-index is not only limited and unfair, but it is severely distorting the priorities of the new generations of scientists in Mexico. Scientists must not forget that we are subsidized with public resources, which leads to not only being widely cited at the international level, but also to contribute to the formation of human resources, to the resolution of local and national problems, to influence the generation of Public Policies and in the social appropriation of knowledge. Therefore, the need to manage a system that considers these aspects is essential in order to evaluate the possible impact of the work of each researcher.</p> Alfredo Ortega-Rubio Bernardo Murillo-Amador Enrique Troyo-Diéguez Ricardo David Valdez-Cepeda Copyright (c) 2021 REVISTA TERRA LATINOAMERICANA 2021-01-17 2021-01-17 39 10.28940/terra.v39i0.895