Sodium N-methyldithiocarbamate impact on soil bacterial diversity in greenhouse tomato (Solanum lycopersicum L.) crop

The constant use of sodium N-methyldithiocarbamate (metam sodium: MS) in protected agriculture in México has attracted the attention of researchers and producers on their effects on the environment. The objective of this study was to evaluate the impact of MS on the bacterial community structure in an agricultural soil with tomato crop (Solanum lycopersicum L.) considering the different phenological stages of the crop. The experiment was carried out in a greenhouse, with a completely randomized block design with two treatments: 1) without MS and 2) with application of 400 L·ha-1 of MS. For the determination of the bacterial structure, the biodiversity indexes of richness (S), diversity (H') and equity (J'), identification of operational taxonomic units (OTU) were used through the T-RFLP technique. Application of MS in soil showed no significant effect on bacterial richness. However, the application of MS does alter the structure of the bacterial community (H' and J') in each of the tomato phenological stages. Finally, future studies which include the evaluation of the effects of MS on the physiology of intensive crops and functions in the different soil types are need.The constant use of sodium N-methyldithiocarbamate (metam sodium: MS) in protected agriculture in México has attracted the attention of researchers and producers on their effects on the environment. The objective of this study was to evaluate the impact of MS on the bacterial community structure in an agricultural soil with tomato crop (Solanum lycopersicum L.) considering the different phenological stages of the crop. The experiment was carried out in a greenhouse, with a completely randomized block design with two treatments: 1) without MS and 2) with application of 400 L·ha-1 of MS. For the determination of the bacterial structure, the biodiversity indexes of richness (S), diversity (H') and equity (J'), identification of operational taxonomic units (OTU) were used through the T-RFLP technique. Application of MS in soil showed no significant effect on bacterial richness. However, the application of MS does alter the structure of the bacterial community (H' and J') in each of the tomato phenological stages. Finally, future studies which include the evaluation of the effects of MS on the physiology of intensive crops and functions in the different soil types are need

Effect of poultry manure and biosolid mixed with European turbe for cucurbit seedling production

En México, la turba de Sphagnum (peat moss), es el principal sustrato utilizado para la producción de plántulas de hortalizas en bandeja de poliestireno, su precio es elevado por ser de importación, lo que hace necesario estudiar alternativas de menor costo. Por lo anterior, se propone mezclar la turba con materiales orgánicos de origen local como la gallinaza (G) y biosólido (B) para producir plántulas de pepino (Cucumis sativus L.) y calabacita (Cucurbita pepo L.). Ocho mezclas de material orgánico-turba fueron evaluadas para cada especie: 1) 4% G + 96% turba; 2) 8% G + 92% turba; 3) 12% G + 88% turba; 4) 16% G + 84% turba; 5) 4% B + 96% turba; 6) 8% B + 92% turba; 7) 12% B + 88% turba; 8) 16% B + 84% turba, el tratamiento testigo fue 100% turba. En los resultados se destaca, en pepino, la mezcla con 16% de biosólido que afectó positivamente en unidades SPAD (Soil Plant Analysis Development), diámetro de tallo y área foliar, mientras que la mezcla con 12% de gallinaza aumentó peso seco de parte aérea y total (P ≤ 0,05). En calabacita, la mezcla con 16% de gallinaza incrementó área foliar (P ≤ 0,05). En las variables de altura, peso seco de raíz y balance de plántula no se encontraron diferencias significativas en ambas especies y mezclas. Se concluye que mezclas de turba europea (peat moss) con gallinaza o biosólido, son una importante alternativa técnica y económica para la producción de plántulas en pepino y calabacita.In Mexico, Sphagnum turbe (peat moss) is the main substrate used for the production of vegetable seedlings in polystyrene trays. It is imported and thus has an elevated price, therefore some lower cost alternatives need to be addressed. This work proposes a mixture of peat with local organic materials as poultry manure (PM) and biosolid (B) to produce cucumber (Cucumis sativus L.) and zucchini (Cucurbita pepo L.) seedlings. Eight mixtures of organic material-peat were evaluated for each species: 1) 4% PM + 96% peat; 2) 8% PM + 92% peat; 3) 12% PM + 88% peat; 4) 16% PM + 84% peat; 5) 4% B + 96% peat; 6) 8% B + 92% peat; 7) 12% B + 88% peat; 8) 16% B + 84% peat, and 100% peat as control. Compared with the control, the mixture with 16% of biosolid affected positively SPAD (Soil Plant Analysis Development) units, stem diameter and leaf area in cucumber seedlings, while the mixture with 12% of poultry manure increased aerial and total dry weight (P ≤ 0.05). In zucchini, the mixture with 16% of poultry manure increased leaf area (P ≤ 0.05). No significant differences were found in height, root dry weight and seedling balance in both species and mixtures. We concluded that use of peat moss mixed with poultry manure or biosolid represents an important technical and economic alternative for cucumber and zucchini seedling production.Fil: Carballo Méndez, Fernando de Jesús. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Rodríguez Ortiz, Juan Carlos. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: García Hernández, José Luis.Fil: Alcalá Jáuregui, Jorge Alonso. Universidad Autónoma de San Luis Potosí. Facultad de AgronomíaFil: Preciado Rangel, Pablo. Instituto Tecnológico de Torreón (México)Fil: Rodríguez Fuentes, Humberto. Universidad Autónoma de Nuevo León (México). Facultad de Agronomía.Fil: Villarreal Guerrero, Federico. Universidad Autónoma de San Luis Potosí. Facultad de Agronomí

Contaminación por metales pesados en sedimentos de un área ribereña en San Luis Paotosí, México

The aim of this study was to determine the presence of heavy metal in sediments of a fragmented riparian area, as an indicator of environmental pollution in San Luis Potosi, Mexico. Eleven sampling points, including four different land uses were established: Pond, Agriculture, Livestock and Rural Settlement. Sediment samples were taken during the seasons of spring, summer and autumn 2010, and winter 2011. The technique of ICP-MS was used to determine Pb, Cd, Cu, and Zn data analysis was performed with Minitab®. Land use has an effect on the accumulation of Cu, Zn and Cd, with the agricultural area containing the highest concentrations. The season was a significant factor for concentrations of Zn, Cd and Pb, emphasizing spring 2010 and autumn 2010, respectively. Significant correlations were found between Cu-Zn (r = 0.746), Pb-Cu (r = 0.635) and Cd-Zn (r = 0.720). The normal limits of Cu, Cd, Zn and Pb in sediments established by the Canadian Environmental Quality Guidelines were exceeded. By using other scientific and technical sources, maximum levels of Cu, Cd and Pb were defined with a condition of high pollution. This condition is attributed to the land use change dynamics, to wastewater discharges, and urban, agricultural and livestock wastes. Thus, a further environmental assessment is recomended for the study area.Se determinó la presencia de metales pesados en sedimentos de un sistema ribereño fragmentado por usos de suelo como indicador de contaminación ambiental en San Luis Potosí, México. Se establecieron once puntos de muestreo considerando los usos de suelo: Estanque, agrícola, Asentamiento rural y Ganadero. Durante las estaciones de primavera, verano y otoño de 2010 e invierno 2011, se tomaron muestras de sedimentos. Se utilizó la técnica de ICP-MS para determinar Pb, Cd, Cu and Zn y los datos fueron analizados en Minitab®. El uso de suelo incide en la acumulación de Cu, Zn y Cd, siendo la zona agrícola la que cuenta con mayores concentraciones. La estación fue significativa respecto de las concentraciones de Zn, Cd y Pb, destacando primavera 2010 y otoño 2010 respectivamente. Asimismo, fueron encontradas correlaciones significativas entre Cu-Zn (r = 0,746), Pb-Cu (r = 0,635) y Cd-Zn (r = 0,720). Los límites normales de Cu, Cd, Zn y Pb en sedimentos establecidos por la Canadian Environmental Quality Guidelines fueron rebasados. Con otras fuentes se definieron que los niveles máximos de Cu, Cd y Pb presentaron una condición alta de contaminación. Esta condición es atribuida a la dinámica de usos de suelo, descargas de aguas residuales, desechos sólidos urbanos, agrícolas y ganaderos, recomendándose continuar su evaluación ambiental

Metallic elements in foliar material and fruits of three tree species as bioindicators

This study aimed to determine the presence of metal elements in fruits and leaves of three tree species as bioindicators in San Luis Potosi, Mexico. Ninety fruit and 90 leaf samples (30 per tree species) were collected at five sites (agricultural, suburban, commercial and services, urban, and mining), using the site and the presence of P. laevigata, S. molle, and A. farnesiana as references. Total concentrations of 13 metal elements were determined using an inductively coupled plasma mass spectrometer (ICP-MS). The species were significantly affected by Co, As, and Pb (ANOVA, p≤0.05). Considering the land use and the species, the contents determined in the leaves and fruits of the three species had sufficient and phytotoxic contents of Al, Cd, Co, Ni, Mn, Ti, and Cr, and excessive ranges with the possible phytotoxic effect of As, Cu, Pb, Zn, V, and Fe. The A. farnesiana had the highest concentrations of 12 heavy metals analyzed (HM). The variation in total metal concentrations between leaves and fruits ranged from 84.70 to 99.06%, with V, As, and Cr being prominent. The functionality of these tree species as phytoremediators and bioindicators is reviewed to evaluate environmental impacts on land use. Highlights Tree species represent a potential bioindicator for studying environmental pollutants due to their ability to accumulate heavy metals. The variation in total metal concentrations between leaves and fruits ranged from 84.70 to 99.06% The contents determined in the leaves and fruits of the three species trees had sufficient and phytotoxic HM contents. The tree species have phytoremediators capacity to evaluate environmental impacts and environmental contamination of land use.This study aimed to determine the presence of metal elements in fruits and leaves of three tree species as bioindicators in San Luis Potosi, Mexico. Ninety fruit and 90 leaf samples (30 per tree species) were collected at five sites (agricultural, suburban, commercial and services, urban, and mining), using the site and the presence of P. laevigata, S. molle, and A. farnesiana as references. Total concentrations of 13 metal elements were determined using an inductively coupled plasma mass spectrometer (ICP-MS). The species were significantly affected by Co, As, and Pb (ANOVA, p≤0.05). Considering the land use and the species, the contents determined in the leaves and fruits of the three species had sufficient and phytotoxic contents of Al, Cd, Co, Ni, Mn, Ti, and Cr, and excessive ranges with the possible phytotoxic effect of As, Cu, Pb, Zn, V, and Fe. The A. farnesiana had the highest concentrations of 12 heavy metals analyzed (HM). The variation in total metal concentrations between leaves and fruits ranged from 84.70 to 99.06%, with V, As, and Cr being prominent. The functionality of these tree species as phytoremediators and bioindicators is reviewed to evaluate environmental impacts on land use. Highlights Tree species represent a potential bioindicator for studying environmental pollutants due to their ability to accumulate heavy metals. The variation in total metal concentrations between leaves and fruits ranged from 84.70 to 99.06% The contents determined in the leaves and fruits of the three species trees had sufficient and phytotoxic HM contents. The tree species have phytoremediators capacity to evaluate environmental impacts and environmental contamination of land use

Indicators of restoration strategies in land uses: metallic and non-metallic elements

Land management practices can have an impact on the environmental quality of soil and contribute to identifying the source of its pollution. The objective of this study was to determine presence of metallic and non-metallic elements as indicators of land use impact (livestock management, restoration strategies and without management practices) in the Monte Caldera communal lands located in Cerro de San Pedro, San Luis Potosi, Mexico. Eighteen samples were collected at depths of 0-10 cm and 10-20 cm for each land use. Total concentrations of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu were determined by X-ray fluorescence. Mean concentrations ranged in the following order: Ti>Zr>Rb>V>Sr>Zn>Cr>Pb> Cu>Th>U>As, with concentrations for Ti, Cr, Th, U and As exceeding technical reference values for phytotoxic soils. Significant differences were evidenced by ANOVA between land use (Th, Pb, Rb, Cu) and soil depth (U, Pb, and As). Land use practices associated with restoration resulted in a positive environmental impact. These findings underscore the need to conduct follow-up studies in the area and further examine the relationship of such practices with other environmental factors. Highlights: Soil management practices can affect the environmental quality of this resource and help diagnose the source of its contamination. It is necessary to evaluate the Impact of land use on livestock management, restoration strategies, and without management or conservation areas. By X-ray fluorescence technique the total concentration of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu was determined. Ti, Cr, Th, U and As exceed the technical reference values for consideration as phytotoxic in soils. Land use associated with reclamation practices is an indicator of a positive influence on improving soil quality.Land management practices can have an impact on the environmental quality of soil and contribute to identifying the source of its pollution. The objective of this study was to determine presence of metallic and non-metallic elements as indicators of land use impact (livestock management, restoration strategies and without management practices) in the Monte Caldera communal lands located in Cerro de San Pedro, San Luis Potosi, Mexico. Eighteen samples were collected at depths of 0-10 cm and 10-20 cm for each land use. Total concentrations of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu were determined by X-ray fluorescence. Mean concentrations ranged in the following order: Ti>Zr>Rb>V>Sr>Zn>Cr>Pb> Cu>Th>U>As, with concentrations for Ti, Cr, Th, U and As exceeding technical reference values for phytotoxic soils. Significant differences were evidenced by ANOVA between land use (Th, Pb, Rb, Cu) and soil depth (U, Pb, and As). Land use practices associated with restoration resulted in a positive environmental impact. These findings underscore the need to conduct follow-up studies in the area and further examine the relationship of such practices with other environmental factors. Highlights: Soil management practices can affect the environmental quality of this resource and help diagnose the source of its contamination. It is necessary to evaluate the Impact of land use on livestock management, restoration strategies, and without management or conservation areas. By X-ray fluorescence technique the total concentration of Zr, Sr, U, Th, Pb, As, Rb, Cr, V, Ti, Zn, and Cu was determined. Ti, Cr, Th, U and As exceed the technical reference values for consideration as phytotoxic in soils. Land use associated with reclamation practices is an indicator of a positive influence on improving soil quality

Nanocompuesto de Nitrógeno como Fertilizante de Liberación Lenta en Columnas de Suelo con Plantas de Lechuga

El uso continuo de fertilizantes nitrogenados en exceso genera riesgos ambientales al aumentar en el suelo la acumulación, volatilización y lixiviación de nitratos, que provocan pérdidas y baja eficiencia en la utilización de N. En este estudio, el objetivo fue evaluar la aplicación de nanocompuestos nitrogenados (NCN) como fertilizante de liberación lenta en el suelo y su efecto en el crecimiento del cultivo de lechuga. El NCN se preparó por la sorción de un surfactante catiónico en una arcilla de bentonita. El estudio se realizó en columnas de suelo, los tratamientos evaluados fueron relaciones de NCN y fertilizante convencional (FC) 25/0, 50/0, 75/0 y 100/0, 0/100, 25/75, 50/50 y 75/25. Las variables evaluadas fueron: peso fresco, biomasa seca, área foliar, conductividad eléctrica, concentración de NO3- en lixiviado y hoja, unidades SPAD y NDVI, además de la liberación del NCN en agua desionizada. Los resultados obtenidos indican que después de 40 días los tratamientos con NCN igualaron al control excepto el tratamiento 25/0 que redujo las variables peso fresco 20% y el área foliar 18% con respecto al control 0/100. Los valores de SPAD y NVDI no tuvieron diferencias significativas entre tratamientos. Las relaciones NCN/FC 0/100, 50/50 y 75/25 aumentaron 19% la concentración de nitratos en hojas. El tratamiento 100/0 aumentó biomasa seca total con 48%, 87% el volumen radical y 73% la biomasa seca de raíz. Los resultados de la liberación en agua desionizada confirmaron que el NCN libera gradualmente nitratos y en mayor cantidad que lo calculado. Finalmente, se concluye que el material nanocompuesto tiene el potencial de usarse como fertilizante de lenta liberación al aumentar crecimiento, por lo que podría ser una alternativa para reducir el uso de fertilizantes convencionales y disminuir las pérdidas de nitrógeno en suelo

Efecto de gallinaza y biosólido en mezcla con turba europea para producción de plántulas de cucurbitáceas

In Mexico, Sphagnum turbe (peat moss) is the main substrate used for the production of vegetable seedlings in polystyrene trays. It is imported and thus has an elevated price, therefore some lower cost alternatives need to be addressed. This work proposes a mixture of peat with local organic materials as poultry manure (PM) and biosolid (B) to produce cucumber (Cucumis sativus L.) and zucchini (Cucurbita pepo L.) seedlings. Eight mixtures of organic material-peat were evaluated for each species: 1) 4% PM + 96% peat; 2) 8% PM + 92% peat; 3) 12% PM + 88% peat; 4) 16% PM + 84% peat; 5) 4% B + 96% peat; 6) 8% B + 92% peat; 7) 12% B + 88% peat; 8) 16% B + 84% peat, and 100% peat as control. Compared with the control, the mixture with 16% of biosolid affected positively SPAD (Soil Plant Analysis Development) units, stem diameter and leaf area in cucumber seedlings, while the mixture with 12% of poultry manure increased aerial and total dry weight (P ≤ 0.05). In zucchini, the mixture with 16% of poultry manure increased leaf area (P ≤ 0.05). No significant differences were found in height, root dry weight and seedling balance in both species and mixtures. We concluded that use of peat moss mixed with poultry manure or biosolid represents an important technical and economic alternative for cucumber and zucchini seedling production.En México, la turba de Sphagnum (peat moss), es el principal sustrato utilizado para la producción de plántulas de hortalizas en bandeja de poliestireno, su precio es elevado por ser de importación, lo que hace necesario estudiar alternativas de menor costo. Por lo anterior, se propone mezclar la turba con materiales orgánicos de origen local como la gallinaza (G) y biosólido (B) para producir plántulas de pepino (Cucumis sativus L.) y calabacita (Cucurbita pepo L.). Ocho mezclas de material orgánico-turba fueron evaluadas para cada especie: 1) 4% G + 96% turba; 2) 8% G + 92% turba; 3) 12% G + 88% turba; 4) 16% G + 84% turba; 5) 4% B + 96% turba; 6) 8% B + 92% turba; 7) 12% B + 88% turba; 8) 16% B + 84% turba, el tratamiento testigo fue 100% turba. En los resultados se destaca, en pepino, la mezcla con 16% de biosólido que afectó positivamente en unidades SPAD (Soil Plant Analysis Development), diámetro de tallo y área foliar, mientras que la mezcla con 12% de gallinaza aumentó peso seco de parte aérea y total (P ≤ 0,05). En calabacita, la mezcla con 16% de gallinaza incrementó área foliar (P ≤ 0,05). En las variables de altura, peso seco de raíz y balance de plántula no se encontraron diferencias significativas en ambas especies y mezclas. Se concluye que mezclas de turba europea (peat moss) con gallinaza o biosólido, son una importante alternativa técnica y económica para la producción de plántulas en pepino y calabacita

Un artículo Red Internacional de Impacto Ambiental Agropecuario: México-Argentina: Red Internacional de Impacto Ambiental

Red Internacional de Impacto Ambiental Agropecuario: México-Argentina El  conocimiento y la concientización de la sociedad sobre los problemas ambientales y el seguimiento de los objetivos y principios del desarrollo sustentable detona la colaboración académica y científica desde un contexto local a global. Por tal motivo, desde 2010 se da el acercamiento y antecedente para que en 2014 se diera la creación de una red de colaboración académica y científica entre Grupos de Investigación de México-Argentina, particularmente entre la Facultad de Agronomía y Veterinaria (UASLP), Facultad de Ciencias Agrarias (UNCUYO) y del Instituto Argentino de Investigaciones de las Zonas Áridas (IADIZA-CONICET). Trasciende no solo el resultado de producción científica, académica, sino un estrecho intercambio cultural y de experiencias que buscan compartir con futuros profesionistas e investigadores.&nbsp

Ensayo en invernadero de abonos verdes sobre las propiedades del suelo, producción de acelga e implicaciones ambientales

In this trial, legumes dolichos beans (Lablab purpureosL. ex Sweet) and yorimon beans (Vigna unguiculataL. Walp) as green manureswere studied. The objectives of the study were to evaluate the ability to capture carbon and fix nitrogen, as well as to measure the effects of its incorporation in the soil, the production of chard (Beta vulgarisvar. cicla L.) and to analyze the environmental implications. In the results, L. purpureosproduced 1932 kg of dry matter in 90 days after sowing (869 kg ha-1of C) and fixed 30 kg of N ha-1in its tissues, while V. unguiculataproduced 2040 kg of dry matter in 80 days after sowing (918 kg ha-1of C) and fixed 40 kg of N ha-1in its tissues. The soil effects were not significant in both AV, compared to the control treatment (without AV). However, both promoted an increase in the weight of chard (40% in L. purpureosand 31% in V. unguiculata). Environmentally, green manures canreduce the carbon footprint by 280 kg ha-1of CO2equivalent by dispensing with synthetic nitrogenous chemical fertilizers in the production of chard. Green manures, as a source of nutrients, especially N, could form part of the integral management of thesoil in the horticultural production systems of semi-arid zonesEn este ensayo se estudió las leguminosas frijol dolichos (Lablab purpureos L. ex Sweet) y frijol yorimón (Vigna unguiculata L. Walp) como abonos verdes. Los objetivos del estudio fueron evaluar la capacidad de capturar carbono y fijar nitrógeno, así como medir los efectos de su incorporación en el suelo, la producción de acelga (Beta vulgaris var. cicla L.) y analizar las implicaciones ambientales. En los resultados L. purpureos produjo 1 932 kg de materia seca en 90 días después de la siembra (869 kg ha-1 de C) y fijó en sus tejidos 30 kg de N ha-1, mientras que V. unguiculata produjo 2 040 kg de materia seca en 80 días después de la siembra (918 kg ha-1 de C) y fijó en sus tejidos 40 kg de N ha-1. Los efectos en el suelo no fueron significativos en ambos AV, en comparación con el tratamiento testigo (sin AV). Sin embargo, ambos promovieron un incremento en peso de acelga (40% en L. purpureos y 31% en V. unguiculata). En lo ambiental, los abonos verdes pueden reducir la huella de carbono en 280 kg ha-1 de CO2 equivalente al prescindir de fertilizantes químicos sintéticos nitrogenados en la producción de acelga. Los abonos verdes, como fuente de nutrientes, en especial N, podrían formar parte del manejo integral del suelo en los sistemas de producción hortícola de zonas semiárida

Elementos traza en fertilizantes y abonos utilizados en agricultura orgánica y convencional

Fertilizers and manures are the major sources of crop nutrients. Their composition of trace elements and transfer into soil by these means has been poorly studied in Mexico. Arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) were determined by inductively coupled plasma mass spectrometry (ICP-MS) in nine nutrient sources used in organic and conventional agroecosystems; vermicompost, compost, Chilean nitrate, phosphate rock, urea, calcium nitrate, diammonium phosphate (DAP), triple superphosphate (TSP) and potassium sulphate. The results show that DAP, TSP, phosphate rock and vermicompost have the highest concentrations of As, Cd and Pb, while Hg was detected only at low concentrations in TSP. Urea, calcium nitrate and potassium sulphate obtained the lowest concentrations. However, vermicompost is the material incorporating most trace elements into the soil when taken as a source of 100 kg N ha-1, the estimated quantities were 17 139, 2 190 and 76 176 mg ha-1 of As, Cd and Pb, respectively. If used as a source of P2O5 or K2O, there will be higher trace elements transfer into the soil.Los fertilizantes y abonos son las principales fuentes de nutrientes de los cultivos. La composición de elementos traza en ellos ha sido poco estudiada en México, así como su ingreso total a los suelos por esta vía.Arsénico (As), cadmio (Cd), mercurio (Hg) y plomo (Pb) fueron determinados por espectrofotometría de masas con plasma acoplado inductivamente (ICP-MS) en nueve fuentes nutrimentales utilizadas en agroecosistemas orgánicos y convencionales; lombricomposta, composta, nitrato chileno, roca fosfórica, urea, nitrato de calcio, fosfato diamónico (DAP), superfosfato triple (SPT) y sulfato de potasio. Los resultados muestran que DAP, SPT, roca fosfórica y lombricomposta poseen las más altas concentraciones de As, Cd y Pb, mientras que Hg sólo fue detectado en SPT a bajas concentraciones. La urea, nitrato de calcio y sulfato de potasio obtuvieron las concentraciones más bajas. Sin embargo, la lombricomposta es el material que más elementos traza incorpora al suelo cuando se toma como fuente de 100 kg de N ha-1, las cantidades estimadas fueron 17139, 2190 y 76176 mg ha-1 deAs, Cd y Pb, respectivamente. En caso de usarse como fuente de P2O5 ó K2O, el ingreso al suelo de elementos traza será aún más alto