Erick Zagal

• PhD Soil Fertility/Plant Nutr.
• Professor (Full) at University of Concepción

Soil organic matter (SOM) quantity drives soil bacterial community composition from the regional to global scale. Qualitative characteristics of SOM are known to affect soil bacterial communities in manipulation experiments. However, it remains unresolved how strongly SOM characteristics affect soil bacterial community composition at the macroscale...

Soil microbial traits and functions play a central role in soil organic carbon (SOC) dynamics. However, at the macroscale (regional to global) it is still unresolved whether (i) specific environmental attributes (e.g., climate, geology, soil types) or (ii) microbial community composition drive key microbial traits and functions directly. To address...

Organic matter accumulation in soil is understood as the result of the dynamics between mineral‐associated (more decomposed, microbial derived) organic matter and free particulate (less decomposed, plant derived) organic matter. However, from regional to global scales, patterns and drivers behind main soil organic carbon (SOC) fractions are not wel...

Organic matter accumulation in soil is understood as the result of the dynamics between mineral-associated (often more decomposed, microbial derived) organic matter and free particulate (often less decomposed, plant derived) organic matter. However, at global scales, the patterns and drivers behind main SOC reservoirs are not well understood and re...

The role of soil in the global carbon cycle and carbon–climate feedback mechanisms has attracted considerable interest in recent decades. Consequently, development of simple, rapid, and inexpensive methods to support the studies on carbon dynamics in soil is of interest. Near-infrared spectroscopy (NIRS) has emerged as a rapid and cost-effective me...

RESUMEN Recientemente se ha detectado deficiencia de azufre (S) en los suelos, lo cual afecta la productividad de los cultivos y la absorción de nitrógeno (N). El objetivo de este estudio fue evaluar el efecto de la aplicación de S al suelo sobre la eficiencia en la recuperación de N. En dos suelos, Andisol y Mollisol, se determinó la mineralizació...

Soil nitrogen (N) variability affects the effective application of N fertilizers. The objective of this research was to determine and assess the spatial dependence of soil N in two different soils using spatial sampling and geostatistics fundamentals. An optimized nested sampling design was applied in two sites, using 16 main stations from where so...

Although the maritime Antarctic has undergone rapid warming, the effects on indigenous soil‐inhabiting microorganisms are not well known. Passive warming experiments using open‐top chamber (OTC) have been performed on the Fildes Peninsula in the maritime Antarctic since 2008. When the soil temperature was measured at a depth of 2–5 cm during the 20...

This second edition of the book contains 12 chapters, which aims to: (1) to update existing chapters with the tremendous advances in temperate agroforestry knowledge that have come to light in the last 20 years; and (2) if possible, to add new global regional examples of temperate agroforestry. Several changes have been made to the second edition....

El cambio en el uso del suelo afecta el potencial de secuestro de carbono (C) en todos los ecosistemas. Sin embargo, existe todavía poca información accesible sobre los aspectos del secuestro de C en agroecosistemas ubicados en las zonas templadas del Hemisferio Sur, y especialmente en aquellas zonas con suelos volcánicos. En la región de Aysén, Pa...

In Chile, indigenous forests (mostly Nothofagus sp. and Acacia caven) and plantations of fast-growing exotic species cover 13.5 and 2.4 million ha, respectively. The latter consists principally of Pinus radiata and Eucalyptus sp., but also include cherry (Prunus avium), poplar (Populus sp.), and walnut (Juglans regia). The main silvopastoral system...

The global use of nitrogen (N) fertilizer has increased 10-fold in the last fifty years, resulting in increased N losses via nitrate leaching to groundwater bodies or from gaseous emissions to the atmosphere. One of the biggest problems farmers face in agricultural production systems is the loss of N. In this context, novel biological nitrification...

Soils are an important site of carbon storage. Climate is generally regarded as one of the primary controls over soil organic carbon, but there is still uncertainty about the direction and magnitude of carbon responses to climate change. Here we show that geochemistry, too, is an important controlling factor for soil carbon storage.We measured a ra...

An important N source for rice (Oryza sativa L.) is mineralization of the organic forms of N present in the soil. The correct N determination will help to optimize the amount of fertilizer used. Our objective was to calculate an index that relates crop N uptake from previous N fertilization and N mineralized in rice paddy soils. To do so, we used t...

An approach to derive relationships for defining land degradation and desertification risk and developing appropriate tools for assessing the effectiveness of the various land management practices using indicators is presented in the present paper. In order to investigate which indicators are most effective in assessing the level of desertification...

Indicator-based approaches are often used to monitor land degradation and desertification from the global to the very local scale. However, there is still little agreement on which indicators may best reflect both status and trends of these phenomena. In this study, various processes of land degradation and desertification have been analyzed in 17...

This study was undertaken to measure certain carbon (C) fluxes in a Pinus ponderosa-based silvopastoral systems (SPS) in Patagonia, Chile. Results are compared to those from adjacent 18-year-old managed pine plantations (PPP) and natural prairie (PST). Litter decomposition was determined using the litterbag method. Leached soil solution was collect...

Soil physical fractionation techniques may provide indicators of changing soil organic carbon (SOC) content; however, they have not been widely tested on volcanic soils (Andisols). In this study, we assessed two fractions as potential indicators in volcanic soils, using two sites in Chile converted from natural grassland to arable and mixed crop ro...

Land-use changes can modify soil carbon contents. Depending on the rate of soil organic matter (SOM) formation and decomposition, soil-vegetation systems can be a source or sink of CO2. The objective of this study was to determine the influence of land-use change on SOM distribution, and microbial biomass and respiration in an Andisol of the Chilea...

The intensive use of soils derived from volcanic ash, due to an increase in livestock and agricultural activities, has generated losses from increasing water erosion in the soils, which are reflected in lower production and an increase in the demand for agricultural inputs. Therefore, this study was conducted to evaluate, after three years, the str...

The response to P and water deficiencies of forage Lotus species has not been sufficiently studied in the Andisol and Vertisol soil orders in Chile's marginal areas. A pot experiment under cover was carried out between October 2007 and March 2008 to study the effects of P and soil water availability (SWA) on DM production, P absorption, and P use e...

Soils can act as either sinks or source of greenhouse gas (GHG) depending on how flows are affected by management practices, but limited information is available on volcanic soils. This study aimed to examine the physical protection of C and GHG emissions provided by soil macroaggregates in a cultivated volcanic soil under no-till soil management a...

Central Chile has a Mediterranean climate with a mean annual precipitation of 695 mm, 80% concentrated in winter. In this context, water erosion and inappropriate agricultural management along hillslopes are the major causes of soil degradation. From 2007 to 2010, different agricultural systems were compared: conservation tillage with stubble retai...

No information is available about carbon (C) sequestration potentials in ecosystems on Andisols of the Chilean Patagonia. This study was undertaken to measure the size of C stocks in three predominant ecosystems: Pinus ponderosa-based silvopastoral systems (SPS), pine plantations (PPP) and natural pasture (PST), and examine how clover affect tree g...

Soil organic carbon (SOC) plays a key role in crop productivity and soil quality. Conservation agriculture has a positive effect on SOC accumulation in the surface soil horizons, but little information is available regarding the effect of the removal of crop residues by burning. This study aimed to assess the impact of different types of crop resid...

Available soil N can be lost through ammonia volatilization, nitrate leaching to surface and ground waters, and nitrous oxide emission under intensive systems of agricultural production. Research has shown that phenolic compounds isolated from certain plants influence N cycling in soils, which results in a decrease of N losses and represents a key...

The potential benefits of using a legumes have not been evaluated in the rainfed, cropping systems of central Chile where wheat (Triticum aestivum) is typically grown in rotation with oats (Avena sativa) using high rates of nitrogen (N) fertilizer. Two experiments were initiated to compare unfertilized legume-wheat cropping sequences to the current...

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Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat (Avena sativa L. cv. Supernova-INIA)-wheat (Triticum aestivum L. cv. Pandora-INIA) crop rotation was esta...

Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat (Avena sativa L. cv. Supernova-INIA) - wheat (Triticum aestivum L. cv. Pandora-INIA) crop rotation was es...

This study was undertaken to quantify the carbon (C) sequestration potentials in three predominant ecosystems on the volcanic soils in Patagonia, Chile. The systems were: Pinus ponderosa Dougl. ex P. Laws. – based silvopastoral systems arranged in strips (silvopasture), 18-year-old managed exotic stands (plantation), and natural prairie (prairie),...

Chile has different types of soil and climate conditions that favor a wide range of agricultural activities that can generate potential atmospheric contamination like greenhouse gases (GHG). Nevertheless, the contribution of agricultural soils to atmospheric emissions has yet to be measured in Chile. The aim of this study was to assess seasonal var...

Chile has different types of soil and climate conditions that favor a wide range of agricultural activities that can generate potential atmospheric contamination like greenhouse gases (GHG). Nevertheless, the contribution of agricultural soils to atmospheric emissions has yet to be measured in Chile. The aim of this study was to assess seasonal var...

Despite annual legume pasture are of great importance for dryland agricultural systems in Mediterranean environments, there are few studies of N2 biological fixation (NBF) reported in Chile. In this study the NBF of four annual legume species: subterranean clover (Trifolium subterraneum L.), yellow serradella (Ornithopus compressus L.), arrow-leaf...

The ecosystems of the Mediterranean interior dryland of Chile, dominated by an espinal agroecosystem of Acacia caven (Molina) Molina, show low productivity as a result of soil degradation. The objective of this study was to evaluate litter decomposition of A. caven and Lolium multiflorum Lam. in espinal ecosystems: well preserved (Wp) 50 to 80%, ty...

In agricultural activities, the main greenhouse gases (GHG) are those related to C and N global cycles. The impact of agriculture on GHG emissions has become a key issue, especially when considering that natural C and N cycles are influenced by agricultural development. This review focuses on CO2 and N2O soil emissions in terrestrial ecosystems, wi...

In agricultural activities, the main greenhouse gases (GHG) are those related to C and N global cycles. The impact of agriculture on GHG emissions has become a key issue, especially when considering that natural C and N cycles are influenced by agricultural development. This review focuses on CO2 and N2O soil emissions in terrestrial ecosystems, wi...

The ecosystems of the Mediterranean interior dryland of Chile, dominated by an espinal agroecosystem of Acacia caven (Molina) Molina, show low productivity as a result of soil degradation. The objective of this study was to evaluate litter decomposition of A. caven and Lolium multiflorum Lam. in espinal ecosystems: Well preserved (Wp) 50 to 80%, ty...

Terrestrial stocks of soil carbon (C) are an important part of the global C budget, and are considered in the Kyoto Protocol. However, there have been few studies in forested regions over the influence of land-use changes on volcanic soils (Andisols) and its simulation through models. The objective of this study was to determine the influence of na...

Water flows provided by irrigation systems may be associated with dissolved organic carbon (DOC) content in the soil solution and may modify the mobility of pesticides, such as chlorpyrifos (CHP). These compounds were analyzed under field conditions, evaluating their distribution in the soil profile under excessive irrigation in a Humic Haploxerand...

Soil organic matter (OM) content is a quality indicator, but is an inadequate indicator in the short-term because these changes take place slowly, so dissolved organic components have emerged as an alternative. In volcanic soil subjected to different crop rotations with distinct land use intensity, dissolved organic C and N (DOC and DON) were deter...

Little is known about the chemical composition of soil organic matter in Espinal ecosystems of Acacia caven (Mol) with a gradient of vegetation cover in Chile. A. caven is widespread throughout regions with Mediterranean-type climates in the Southern Hemisphere, where the abundance of this species is associated with the degradation of the native fo...

Labile soil carbon fractions and enzymatic activity are typically more sensitive to changes in soil management practices or environmental conditions than total soil organic matter, and consequently they are well-established as early indicators of change due to crop residue incorporation, soil use or pollution. However, less information has been rep...

Soil organic matter (OM) content is a quality indicator, but is an inadequate indicator in the short-term because these changes take place slowly, so dissolved organic components have emerged as an alternative. In volcanic soil subjected to different crop rotations with distinct land use intensity, dissolved organic C and N (DOC and DON) were deter...

Water flows provided by irrigation systems may be associated with dissolved organic carbon (DOC) content in the soil solution and may modify the mobility of pesticides, such as chlorpyrifos (CHP). These compounds were analyzed under field conditions, evaluating their distribution in the soil profile under excessive irrigation in a Humic Haploxerand...

The present study had the purpose of testing through supervised trials the variability of Chlorpyrifos (CHP) residues associated to a sampling methodology validated in the field, on applying the active ingredient (AI) in an apple orchard, with two different spraying methodologies and at different periods of vegetative development. The persistence o...

Pollution of aquatic fresh water and soil is of great concern in the salmon farming industry. Water is the most important vehicle for the transmission of organic polluting agents, and for that reason the sediments (sludge) near to salmon facilities could become enriched reservoirs of pathogens and chemicals. A solution to this problem could be to i...

The present study had the purpose of testing through supervised trials the variability of Chlorpyrifos (CHP) residues associated to a sampling methodology validated in the field, on applying the active ingredient (AI) in an apple orchard, with two different spraying methodologies and at different periods of vegetative development. The persistence o...

In previous studies, Al extracted by acid ammonium acetate (Ala) or Na-pyrophosphate (Alp), rather than silt or clay content and climate conditions, was the most important factor that controls organic matter (OM) levels in volcanic soils. Here, the hypothesis was tested that Ala is a comparable method (as much as CuCl2) to quantify the proportion o...

La contaminación de los suelos y de los ecosistemas acuáticos de agua dulce es una preocupación constante para la industria de la salmonicultura. El agua es el vehículo más importante para la transmisión de contaminantes orgánicos, y por ello los sedimentos (lodos) próximos a las instalaciones de una piscicultura o salmonicultura pueden convertirse...

Field guide for the southern tour of the the International Conference & Field Workshops on Soil Classification, 9th -17th November, 2008.

Unsustainable management of the “Espinal” agroecosystem of central Chile has progressively lowered the organic matter content and fertility of soil as evidenced by decreasing forage production and lower coverage of espino (Acacia caven (Mol.) Mol.), a leguminous tree. This savannah-type ecosystem includes the soil Cauquenes clay loam (Ultic Palexer...

The intensive use of soils derived from volcanic ash, due to an increase in livestock and agricultural activities, has generated losses from increasing water erosion in the soils, which are reflected in lower production and an increase in the demand for agricultural inputs. Therefore, this study was conducted to evaluate, after three years, the str...

The Acacia caven (Mol) is one of the most widespread tree species of the Mediterranean-type ecosystem of South America, forming the "Espinal" ecosystem characterized by a complex and heterogeneous structure like savannas. In South-Central Chile, these Espinal ecosystems include 2 million hectares of agricultural and agroforestry soil. We analyzed t...

SUMMARY - The "Espinal" is a Mediterranean agroforestry system of the dryland areas of central Chile. Over the past century, the Espinal has become ecologically degraded. In this paper, results from the first four years of a long-term experiment, are presented. The objective was to study the effect of introducing mixtures of annual legumes (mixture...

The intensive use of soils derived from volcanic ash, due to an increase in livestock and agricultural activities, has generated losses from increasing water erosion in the soils, which are reflected in lower production and an increase in the demand for agricultural inputs. Therefore, this study was conducted to evaluate, after three years, the str...

The effects of six crop-pasture rotations were evaluated on properties of soil aggregates in a volcanic soil (Humic Haploxerand) of south-central Chile. Rotations that included intensive cropping without pastures, and crops with short- or long-term pastures were maintained for 12 years after which soil samples were taken at 0–5 and 5–10 cm depths f...

The ‘Espinal’ agroforestry system of the Mediterranean zone of central Chile, which covers an area of 2000 000 ha, is in various stages of degradation due to human activities. The objective of our study was: (i) to determine the effects of the canopy cover of Acacia caven (‘Espino’) on total soil organic carbon (SOC), soil respiration and the labil...

The overexploitation of the natural resources in the Mediterranean-type climate region of Chile, has resulted in natural forest fragmentation and expansion of Acacia caven (Mol), forming the 'Espinal' ecosystem (EE) that includes two million of hectares in the Central part of Chile. The effect of the anthropogenic intervention over the soil organic...

Los parámetros Hidráulicos fueron medidos en un suelo de origen volcánico del Valle Central (Humic Haploxerands) bajo diferentes rotaciones culturales con distinto manejo agronómico e intensidad de uso del suelo y fueron agrupadas en cuatro rotaciones que incluyeron pradera y dos rotaciones intensivas, sin pradera. Las mediciones de conductividad H...

La sobreexplotación de los recursos naturales en la zona Mediterránea de Chile, ocasionó la fragmentación del bosque nativo y la expansión de Acacia caven (Mol), formando los ecosistemas de Espinal (EE) que abarcan dos millones de hectáreas en la zona central de Chile. El efecto de esta intervención antropogénica sobre el carbono orgánico del suelo...

The contribution of biological nitrogen fixation (BNF) to the N nutrition of six annual forage legumes, subterranean clover (Trifolium subterraneum), burr medic (Medicago polymorpha), balansa clover (Trifolium michelianum), Persian clover (Trifolium resupinatum), yellow serradela (Ornithopus compressus), and pink serradela (Ornithopus sativus) was...

Biosolids from urban water and fish farming wastes have increased in the last years in Chile. It has generated the compulsory necessity to look for alternatives for its final disposition, in such a way that it do not constitute risk for the health and environment. In the present study the effects on germination of lettuce seeds ere analyzed as a re...

El manejo agronómico influye en la dinámica de la materia orgánica del suelo (MOS) y sus diferentes fracciones. En este estudio se determinaron fracciones activas de la MOS: fracción liviana libre (FLL), fracción liviana intraagregados (FLI), biomasa microbiana y C-CO2 mineralizado, en un suelo volcánico cultivado con distintas rotaciones, y poster...

La disponibilidad de cama de broiler (CB), mezcla de estiércol de broiler sobre viruta, ha aumentado sostenidamente debido a la mayor producción de carne de ave. El uso de este producto como fertilizante disminuye la contaminación desde zonas de acumulación y a la vez mejora la fertilidad de los suelos. En este estudio se comparó el nivel de macron...

En un suelo Typic Haploxerand, serie Santa Bárbara de la VIII Región se estudió el efecto de la adición de N y P, sobre la mineralización de C y N como indicadores de la tasa de descomposición de paja de trigo (Triticum aestivum L.). Se agregó paja sobre el suelo o incorporada en combinación con aplicaciones de N (0 y 100 mg kg-1 suelo) y P (0 y 65...

Con el objeto de estudiar la eficiencia de uso y la dinámica del N en una rotación, con y sin manejo de residuos, se estableció un experimento con N marcado (15N), en un suelo volcánico (Typic Melanoxerand) bajo condiciones de riego. Se instalaron micro-parcelas con 15N en un ensayo de rotaciones de cuatro años. El 15N se aplicó sólo una vez, como...

The future scenario confronting the agricultural sector will include an increase in international trade agree- ments that will obligate serious consideration of environmental protection. Agriculture includes activities that can impact natural resources of soil, water and also the atmosphere through the liberation of gases that may contribute to glo...

El futuro escenario productivo que enfrentará el sector agropecuario de acuerdos y tratados internacionales marca una clara tendencia que obliga a considerar, en forma seria, las normativas ambientales vigentes en estos tratados y acuerdos, además de su evolución en el tiempo. El sector agropecuario, como una actividad del hombre, genera impactos a...

Fertilizer recommendation systems used to optimize nitrogen fertilization can be divided into three groups: systems based principally on soil analysis, systems based on plant analysis, and systems based on simulation models. One of the available models that describes N flows in plant and soil systems applicable to agricultural ecosystems is the "Ro...

In a Typic Haploxerand soil (Santa Bárbara) from the VIII Region, Chile , the effect of the addition of N and P on mineralization of C and N as indicators of the rate of wheat ( Triticum aestivum L.) straw decomposition was studied. Wheat straw was either left as a cover or incorporated into the soil in combination with N (0 and 100 mg kg-1 soil) a...

Los sistemas de recomendaciones para optimizar la fertilización nitrogenada se pueden dividir en tres grupos: sistemas basados principalmente en análisis de suelos, sistemas basados en análisis de plantas, y sistemas basados en modelos de simulación. Dentro de los modelos existentes que describen el flujo de N en un sistema planta y suelo aplicable...

A partir de un ensayo de rotaciones conducidas por 18 años, en un suelo volcánico de la precordillera de Ñuble (37º09¿ lat. Sur; 72º02¿ long. Oeste), se obtuvieron muestras para determinar los efectos del manejo agronómico sobre el contenido de fracción liviana (FL) de la materia orgánica. Ésta fue separada mediante fraccionamiento físico por densi...

La actividad microbiana en un suelo de origen volcánico del Valle Central (Typic Melanoxerand) fue medida al término de un experimento de 7 años de duración en 6 rotaciones con distinto manejo agronómico e intensidad de uso del suelo. Muestras no alteradas de este suelo fueron incubadas en laboratorio por 30 días bajo condiciones controladas de tem...

Starting from an 18-year experiment with different crop rotations, samples of soil of volcanic origin from the foothills of Ñuble (37º09' S lat.; 72º02' W long.) were obtained in order to determine the effect of agricultural management on light fraction (FL) of the organic matter. FL was separated by density using NaI (d = 1,8 g cm -3 ). Carbon (C)...

Chicory (Cichorium intybus L.) and perennial ryegrass (Lolium perenne L.) are seen as suitable catch crops species in Sweden. Pot experiments were conducted to study C distribution and variations in nitrogen uptake between several varieties of chicory and perennial ryegrass for comparison.A soil amended with Ca(15NO3) (109 and 145 mg N kg−1 soil) a...

The soil tillage system affects incorporation of crop residues and may influence organic matter dynamics. A study was carried out in five 15–20 year old tillage experiments on soils with a clay content ranging from 72 to 521gkg−1. The main objective was to quantify the influence of tillage depth on total content of soil organic carbon and its distr...

In this review some of the mechanisms peas (Pisum sativum L.) have evolved for coping with microorganisms are covered. These adaptations are then compared with ways in which other host plants cope with microorganisms. The aim is to show that there are similarities between symbiotic and pathogenic host-microbe interactions and that a more profound u...

In this study we investigated how N application rate influenced N immobilization and its subsequent remineralization. By incubating soil for 84 days in the laboratory and using 14C-glucose as substrate and four concentrations of 15N-labelled fertilizer addition, we followed changes in labelled and unlabelled inorganic N, soil microbial biomass C an...

A pot experiment was conducted in a 14C-labelled atmosphere to study the influence of living plants on organic-N mineralization. The soil organic matter had been labelled, by means of a 200-days incubation, with 15N. The influence of the carbon input from the roots on the formation of microbial biomass was evaluated by using two different light int...

To examine the influence of plant-microorganism interactions on soil-N transformations (e.g. net mineralization, net immobilization) a pot experiment was conducted in a14C-labelled atmosphere by using different (two annuals, one perennial) plants species. It was assumed that variation in below-ground, microorganism-available C would influence N tra...

Below-ground carbon (C) production and nitrogen (N) flows in the root-zone of barley supplied with high or low amounts of N-fertilizer were investigated. Interest was focused on the effect of the level of N-fertilizer on the production of root-derived C and on gross immobilization (i) and gross mineralization (m) rates. The plants were grown for 46...

The quantity of microbial biomass was measured in a range of soils by the fumigation-incubation (FI) and fumigation-extraction (FE) techniques. The air-dried soils were rewetted and incubated before the measurements were made. The FE method for biomass C was calibrated from the relationship between the flush of extractable organic C (Ec) and microb...

L'irradiation aux hyperfrequences permet de remplacer la technique d'incubation-fumigation pour estimer la biomasse totale du sol. Il semble que les mecanismes de l'action biocide des deux methodes soient differents, comme l'indiquent les rapports C/N de mineralisation. La methode aux hyperfrequences est limitee par les quantites d'argile du sol