Curso de posgrado

MODELOS MATEMATICOS DE SIMULACIÓN EN LA INVESTIGACIÓN AGROPECUARIA: Clima-suelo-planta

Se desarrollan conceptos teóricos sobre la estructura y funcionamiento de los sistemas y se analizan diferentes modelos matemáticos de simulación aplicados al estudio del clima, los cambios en el suelo y el crecimiento de las plantas en ambientes naturales y cultivados. Se plantean diferentes estrategias y se presentan diferentes herramientas para la simulación dentro de los sistemas agropecuarios. Se desarrollan ejercicios de complejidad variable, los que no requieren conocimientos en programación, para simular cambios climáticos, crecimiento de cultivos, dinámica de la materia orgánica, etc.

Docente responsable:

Dr. Juan Alberto Galantini, Comisión de Investigaciones Científicas (Pcia. Bs.As.), CERZOS – Departamento de Agronomía (UNS)

Dictado durante la semana del 30 de octubre al 4 de noviembre, más dos días de presentación de los trabajos finales.

Carga horaria total: 60h

Inscripciones y consultas 
                                   jgalanti@criba.edu.ar  
                                   juangalantini@gmail.com

Detalles del curso

Ecos de las III Jornadas de Suelos de Ambientes Semiáridos

La Asociación Argentina de la Ciencia del Suelo (AACS) llevó adelante las III Jornadas Nacionales de Suelos en Ambientes Semiáridos y II Taller Nacional de Cartografía Digital. Las mismas fueron organizadas en forma conjunta por el INTA, la Comisión de Investigaciones Científicas, el CERZOS (UNS-CONICET) y Universidad Nacional del Sur. Este importante evento se realizó en la ciudad de Bahía Blanca los días 7 y 8 de Septiembre de 2017 con sede en el Centro Científico Tecnológico (CCT), en el Auditórium central de la UAT (Edificio E3) ubicado en el camino La Carrindanga km 7.

Más de 140 inscriptos y 100 contribuciones dieron marco a dos días de intenso intercambio de información para difundir las actividades que los diferentes grupos de trabajo llevan adelante en los Suelos de los Ambientes Semiáridos de nuestro país.

En nombre de la Comisión Organizadora hago llegar el agradecimiento a todos los que participaron, tanto asistentes, panelistas como colaboradores, así como a las instituciones, municipios y empresas que apoyaron de una u otra forma el desarrollo de las Jornadas.

Como coordinador de la Comisión Organizadora, quiero agradecer a todos sus integrantes que hicieron posible estar en cada uno de los detalles, con las dificultades propias de este tipo de reuniones pero con todas las ganas de ayudar a crear ese agradable espacio para el encuentro y el intercambio entre estudiantes y trabajadores de la Ciencia del Suelo.

Para todos aquellos vinculados con los Suelos de Ambientes Semiáridos el encuentro será el próximo año en el Congreso Nacional de la Ciencia del Suelo en Tucumán y dentro de  dos años en las IV Jornadas Nacionales en Córdoba 

Juan A. Galantini

EJES TEMÁTICOS

Política y Gestión de Recursos Naturales

Tecnologías de manejo de suelos y agua de regiones semiáridas.

Evaluación integral de un sistema productivo con diferentes labranzas.

Sistemas alternativos de uso del suelo.

Cartografía digital en ambientes frágiles.

Programa con links

Actas (en preparación) 

COMISIÓN ORGANIZADORA

Juan Alberto Galantini

Matias E Duval

Juan I Vanzolini

Hugo Krüger

María Rosa Landriscini

Liliana Suñer

Oscar Bravo

Ramiro García

Julio Iglesias

Juan Manuel Martínez

Corina Cerda

Josefina Zilio

Gabriela Minoldo

Fabiana Limbozzi

Fernando López 

Invitación a las Jornadas

La Asociación Argentina de la Ciencia del Suelo (AACS), a través de la Comisión Química de Suelos, anuncia que la semana próxima se llevarán a cabo las III Jornadas Nacionales de Suelos en Ambientes Semiáridos y II Taller Nacional de Cartografía Digital. Las mismas son organizadas en forma conjunta por el INTA, la Comisión de Investigaciones Científicas, el CERZOS (UNS-CONICET) y Universidad Nacional del Sur. Este importante evento se realizará en la ciudad de Bahía Blanca los días 7 y 8 de Septiembre de 2017 con sede en el Centro Científico Tecnológico (CCT), en el Auditorium central de la UAT (Edificio E3) ubicado en el camino La Carrindanga km 7.

Tenemos el agrado de informar que contamos con más de 120 inscriptos y 80 contribuciones. Esperamos compartir dos días de intenso intercambio de información para difundir las actividades que los diferentes grupos de trabajo llevan adelante en los Suelos de los Ambientes Semiáridos de nuestro país.

Ejes Temáticos

Política y Gestión de Recursos Naturales

Tecnologías de manejo de suelos y agua de regiones semiáridas.

Evaluación integral de un sistema productivo con diferentes labranzas.

Sistemas alternativos de uso del suelo.

Cartografía digital en ambientes frágiles.

Los contactos para mayor información:

Dr. Juan Galantini (juangalantini@gmail.com) o Dr. Matias Duval (matias.duval@uns.edu.ar)

Para mayor información ver: 

                                              Información Importante      

                                              Programa online

                                              Actas de las Jornadas en Boletín del CERZOS (en construcción)

Cómo llegar y cuánto tiempo (Googlemap)                Hoteles en Bahía Blanca

Comisión Organizadora:

Juan A. Galantini (CIC)

Matias E. Duval (UNS-CERZOS)
Juan I. Vanzolini (INTA H.Ascasubi)

Maria Rosa Landriscini (CERZOS-CONICET)

Liliana Suñer (CIC-UNS)

Hugo Kruger (INTA Bordenave)

Publicaciones Científicas primer semestre 2017

Sa Pereira E, J.A. Galantini, M. Duval. 2017. Use of a three-compartment model to evaluate the dynamics of cover crop residues. Archives of Agronomy and Soil Science 1-7. doi 10.1080/03650340.2017.1296137

ISSN: 0365-0340 (Print) 1476-3567 (Online)

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http://dx.doi.org/10.1080/03650340.2017.1296137

Cover crop (CC) residues protect the soil from erosion and their permanence on the surface is largely influenced by their biochemical constituents. In this study, the dynamics of CC residue decomposition by applying mathematical models was described. The kinetics of decomposition of residues was obtained from a laboratory incubation experiment. Three CC shoot residues were applied on the soil surface and incubated for 362 days (with eight sampling times). Oats and vetch residues decomposed the most than clover, where k values were 3.6 × 10⁻³, 3.7 × 10⁻³ and 5.3 × 10⁻³ day⁻¹, respectively. The three-compartment model (nonstructural carbohydrates, cellulose–hemicellulose and lignin) to simulate residue decomposition presented a close fit between simulated and measured data. The decomposition rate constant (k) of CC can be used to estimate how long residues will remain in the field and how they could affect soil organic carbon.

Keywords: Residue decomposition; oats; vetch; clover

Martínez J.M., J.A. Galantini. 2017. A rapid chemical method for estimating potentially mineralizable and particulate organic nitrogen in Mollisols. Communications in Soil Science and Plant Analysis 48(1) 113-123. doi: 10.1080/00103624.2016.1254230

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http://dx.doi.org/10.1080/00103624.2016.1254230

The objective of this study was to obtain an indicator of labile nitrogen (N) through a cost- and time-saving procedure by evaluating the relationships among potentially mineralizable N (N₀), particulate organic matter N (POM-N) and soil organic N extracted through partial soil digestion with different concentrations of sulfuric acid (H₂SO₄). Soil sampling (0–20 cm) was from nine fields under no-tillage. The N₀ and POM-N were determined by long-term aerobic incubation and soil physical fractionation, respectively. A simple chemical method was developed by soil digestion at 100°C for 4 h with different concentrations of H₂SO₄ (0.1, 0.5, 1, 6, 12, and 24 mol L⁻¹). All acid concentrations showed significant relationships with N₀ as POM-N; however, the best prediction was resulted for 0.5 mol L⁻¹ (R² = 0.90–0.94, respectively), thus using this methodology as soil labile N indicator. This method would optimize N₀ and POM-N estimation in short term and at a low cost.

Keywords: Chemical digestion; labile organic fractions; no-tillage

Behrends K.F., M.A. Soria, M.G. Castiglioni, M. Duval, J. Galantini, H. Morrás. Morpho-structural evaluation of various soils subjected to different use intensity under no-tillage. Soil & Tillage Research 169: 124-137. doi:10.1016/j.still.2017.01.013

ISSN: 0167-1987

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According to many evidences, in Argentina, no-tillage (NT) coupled with soybean monoculture leads to adverse soil structure features. While some farmers have simplified the production system through soybean monoculture others have intensified the land-use by increasing the number and diversity in the crop sequence. The effects of this intensification, in terms of soil structural quality, are contradictory, possibly caused by the increase of machinery traffic. In order to assess soil structural quality and the performance of selected morpho-structural variables with different levels of intensification, we analyzed plots under NT with high and low crop sequence intensification (Good −GAP- and Poor −PAP-, agricultural practices respectively) and reference plots in four soils (two Argiudolls, an Haplustoll and an Hapludert) of the Argentinian Pampean region. The morpho-structural variables assessed were Visual Evaluation of Soil Structure at field scale (VESS), visible porosity (Vp), roundness (Rd), eccentricity (Ecc) and 3-D aggregate features (faces, corners and edges). Plots with higher frequency of cereals in the sequence (GAP) presented on average higher VESS scores, higher Vp values and less rounded aggregates with more faces and corners, suggesting that crop sequence intensification induces favorable structural features. VESS, Vp, number of faces and corners were strongly correlated with aggregate stability tests mainly with the fast and fast10s test (r: −0.56, −0.74; 0.48, 0.52; 0.46, 0.49 and 0.42, 0.50, respectively) and with the more labile organic carbon fractions −POCc and POCf- (r: −0.49, −0.5; 0.5, ns; 0.38, 0.48 and 0.31, 0.43, respectively). These observations suggest that the variables examined, concerning aggregates and pores were sensitive to changes in crop sequence and are useful soil quality indicators. However, the occurrence of platy structures also under GAP shows the need to adjust the VESS method to the NT system. Besides, the effect of agricultural intensification on soil morphology was modulated by soil type. In consequence, this last factor has also to be considered for the definition of a quality indicator to track the effect of crop sequences intensification under no-till management.

Keywords: Aggregate morphology; Image analyses; VESS

Martínez J.M., J.A. Galantini., M Duval. 2017. Tillage effects on labile pools of soil organic nitrogen in a semi-humid climate of Argentina: A long-term field study. Soil & Tillage Research 169:71-80. DOI 10.1016/j.still.2017.02.001

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Links

Tillage systems strongly affect nitrogen (N) mineralization. However, there is still only limited information on the relationship between N in labile soil organic matter (SOM) fractions and crop N uptake under different tillage systems in areas with poor water availability. This study discusses the long-term effect of two tillage systems on i) the N-content in labile organic matter fractions and their relationship with the N mineralization potential at three depths (0–5; 0–10 and 0–20 cm), ii) the factors that affect the N mineralization potential, and iii) the relationship between potentially mineralizable N (N0) and crop N uptake in a semi-humid climate. In a long-term experiment, a Typic Argiudoll was sampled under two contrasting tillage systems: no-tillage (NT) and conventional tillage (CT). The soil sampling was performed over four years of the crop sequence (2003, 2009, 2010 and 2011) when the plots were sown with winter wheat (Triticum aestivum L.). They were analyzed for N0 in the form of anaerobic N, soil organic nitrogen (SON), physically separated SOM fractions and crop N uptake. Higher values of SON and labile soil N fractions were observed under NT at all three depths. Significant differences in N0 were found between the tillage systems, with greater values under NT. Significant (P < 0.05) and positive correlations between N0 and fine particulate organic carbon (fPOM-C) (r ≥ 0.66) were found in CT and in NT at the three depths, whereas highly significant (P < 0.001) and negative relationships between N0 and fine particulate organic N (fPOM-N) (r ≥ −0.83) were found under both tillage systems at 0–5 and 0–10 cm. The most pronounced difference in these relationships between tillage systems was observed at the 0–5 cm soil depth. Significant correlations of N0 with residue input from previous crops and the fallow period were observed under both tillage systems and for all three depths. Regarding the relationships between N0 and wheat N uptake, no significant correlations were found for any tillage system or depth. Soil organic N fractions were shown to be strongly influenced by the residue input from the previous crop and by variable weather conditions during the fallow period. The higher content of SON fractions under NT was associated with a higher N mineralization potential, however, it did not result in increased N availability and N uptake by wheat, because of climatic conditions during the crop growing season.

Keywords: Potentially mineralizable N; Soil labile fractions; Tillage systems

Vanzolini J.I., J.A. Galantini, J.M. Martínez, L. Suñer. 2017. Changes in soil pH and phosphorus availability during decomposition of cover crop residues. Archives of Agronomy and Soil Science 63 () http://dx.doi.org/10.1080/03650340.2017.1308493

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The aim of this study was to determine the effect of winter cover crop (CC) residues on soil pH and phosphorus (P) availability. Three incubation assays were performed in pots using two CC: vetch (V) (Vicia villosa Roth.) and oats (Oa) (Avena sativa L.). Soil samples were taken from 10 sites at 0–20-cm depth. The rate of residues were 0 (D0), 10 (D1), 20 (D2), 30 (D3), and 40 (D4) g dry matter kg⁻¹ soil and the soil sampling was after 10, 20, 30, 60, 90, and 120 days of incubation. Soil pH, extractable P (Pe), and soil organic matter (SOM) and its fractions were determined. The pH increase was correlated with the rate applied (D1 < D2 < D3 < D4). No differences were found for pH comparing V and Oa residues with low residue rates. Soil pH changes were dependent from initial pH and SOM fractions in different soils across the incubation period. The multiple regression models showed that the pH changes were dependent on initial pH level and SOM fractions with a high R² (0.81). CC residues and its quantities produced different changes on pH – especially at the beginning of the incubation – which influenced the P availability.

Publicaciones 2016 en revistas del exterior

Duval M.E., J.A. Galantini, J.M. Martinez, F.M. López, L. Wall. 2016. Sensitivity of different soil quality indicators to assess sustainable land management: Influence of site features and seasonality. Soil & Tillage Research 159: 9-22.

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The turnover rate of labile organic fractions varies continuously due to different soil uses and managements, weather conditions and time of sampling. The aim of this study was to quantify the effect of different agricultural management, season and soil type on soil organic carbon (SOC) and its different fractions. The study was conducted on four sites located in the Argentinean Pampas. In each site, three treatments were defined: Good Agricultural Practices (GAP), Poor Agricultural Practices (PAP) and Natural Environment (NE). During two consecutive years (2010 and 2011) and at two different times (February and September) undisturbed soil samples were taken at0-20 cm depth. Variables assessed included: SOC and its organic fractions: coarse and fine particulate organic carbon (POCc and POCf, respectively), SOC associated with a mineral fraction (MOC), total and soluble carbohydrates (CHt and CHs, respectively), bulk density, and large pores (P>30). Also, indices associated with soil and management variables were determined. SOC reductions caused by agricultural practices were mainly from POCc. This fraction represented 34-52% and 50-74% for PAP and GAP, respectively, of the observed in NE. The carbon pool index (CPI) shows that agricultural treatments induced greater variations in all the labile organic fractions compared with SOC and MOC. In turn, the magnitude of variability was different among fractions, where temporal fluctuations increased according to the following order MOC< SOC <POCf≤CHt<CHs ≤ POCc. Independently of the soil type, the CPI was a sensitive indicator of soil quality in these systems under no-tillage. The multivariate analysis has proven to be an efficient analytical methodology for the identification of soil indicators that respond to agricultural practices, in which chemical properties (POCf and CHt), physical (BD and P>30), and indices (SOC:clay, structural index and intensification sequence index) were the variables that best explained the total variance of information of the four sites. Therefore, these indicators/indices should be included in any minimum data set for evaluating the agricultural soil quality under no-tillage in the studied area.

Keywords: Soil organic carbon; Organic fractions; Multivariate analysis

Galantini, J.A.; M. Duval; J.M. Martinez; V. Mora; R. Baigorri & J.M. García-Mina. 2016. Quality and quantity of organic fractions as affected by soil depth in an argiudoll under till and no-till systems. International Journal of Plant & Soil Science 10 (5) - doi:10.9734/IJPSS/2016/25205

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The turnover rate of labile organic fractions varies continuously due to different soil uses and managements, weather conditions and time of sampling. The aim of this study was to quantify the effect of different agricultural management, season and soil type on soil organic carbon (SOC) and its different fractions. The study was conducted on four sites located in the Argentinean Pampas. In each site, three treatments were defined: Good Agricultural Practices (GAP), Poor Agricultural Practices (PAP) and Natural Environment (NE). During two consecutive years (2010 and 2011) and at two different times (February and September) undisturbed soil samples were taken at0-20 cm depth. Variables assessed included: SOC and its organic fractions: coarse and fine particulate organic carbon (POCc and POCf, respectively), SOC associated with a mineral fraction (MOC), total and soluble carbohydrates (CHt and CHs, respectively), bulk density, and large pores (P>30). Also, indices associated with soil and management variables were determined. SOC reductions caused by agricultural practices were mainly from POCc. This fraction represented 34-52% and 50-74% for PAP and GAP, respectively, of the observed in NE. The carbon pool index (CPI) shows that agricultural treatments induced greater variations in all the labile organic fractions compared with SOC and MOC. In turn, the magnitude of variability was different among fractions, where temporal fluctuations increased according to the following order MOC< SOC <POCf≤CHt<CHs ≤ POCc. Independently of the soil type, the CPI was a sensitive indicator of soil quality in these systems under no-tillage. The multivariate analysis has proven to be an efficient analytical methodology for the identification of soil indicators that respond to agricultural practices, in which chemical properties (POCf and CHt), physical (BD and P>30), and indices (SOC:clay, structural index and intensification sequence index) were the variables that best explained the total variance of information of the four sites. Therefore, these indicators/indices should be included in any minimum data set for evaluating the agricultural soil quality under no-tillage in the studied area.

Keywords: Soil organic carbon; Organic fractions; Multivariate analysis

Duval M., J.A. Galantini, Julia E. Capurro, J.M. Martinez, F.M. López. 2016. Use of different winter cover crops species in soybean monoculture: effects on soil organic carbon and its fractions. Soil & Tillage Research 161:95-105 doi:10.1016/j.still.2016.04.006

 ISSN: 0167-1987

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The current agricultural production systems in the Pampas Region have been significantly simplified by cultivating large land areas under no tillage (NT), where soybean is the predominant crop. These systems with long periods of fall-winter fallow and poor annual input of carbon (C) into the soil lead to soil degradation, thereby affecting physical and chemical properties. A 6-year cover crop study was carried out on a Typic Argiudoll under NT in the south of Santa Fe, Argentina. Various winter species were used as cover crops: wheat (W), oat (O), vetch (V), an oat + vetch mixture (O + V) and a control (Ct) treatment without a cover crop. We examined the influence of cover crops on the following soil organic C-fractions: coarse particulate organic carbon (POCc), fine particulate organic carbon (POCf) and mineral-associated organic carbon (MOC) from 2008 to 2011. Aboveground carbon input by the cover crops was related to the June to October rainfalls. In general, the W and O treatments supplied a higher amount of C to the soil; these gramineous species produced 22 and 86% more biomass than O + V and V. The water cost of including cover crops ranged from 13 to 93 mm compared with Ct. However, this water-use did not affect soybean yields. On average, gramineous species (pure stand or mixture) supplied more than 3.0 Mg C ha⁻¹ year⁻¹ to the soil, whereas V supplied less than 2.0 Mg C ha⁻¹ year−1. Increase in the mean annual C-input by residues into the soil (cover crop + soybean) explained most SOC variation (R² = 0.61; p < 0.05). This relationship was more evident with labile soil organic fractions, both for POCc (R² = 0.91; p < 0.001) and POCc + POCf (R² = 0.81; p < 0.001). The stratification ratios of SOC (SI, 0–5:10–20 cm) reflected differences among treatments, where >2.0 for W; 1.7 for O, O + V and V, and <1.5 for Ct. Soil physical fractionation by particle size showed that cover crops affected the most dynamic fraction directly associated with residue input (POCc) at 0–5 and 5–10 cm. At 0–5 cm, the effects were observed in the most transformed fractions (MOC and POCf) 4 years after the experiment started, whereas at 0–20 cm, differences in the labile fractions (POCc and POCf) were found at the end of the experiment (6 years). Although C-input by the cover crops fueled decomposition of labile soil organic fractions, concentration of surface SOC and its associated fractions (POCc, POCf and MOC) was modified after 6 years. This effect became noticeable during the third year when the plots under cover crops showed a higher SI than the traditional fallow.

Keywords Wheat; Labile fractions; No-tillage

Zalba P., N.M. Amiotti, J.A. Galantini, S. Pistola. 2016. Soil humic and fulvic acids from different land use systems evaluated by E4/E6 ratios. Communications in Soil Science and Plant Analysis 47 (13-14) 1675-1679. Doi 10.1080/00103624.2016.1206558

ISSN: 0010-3624 (Print) 1532-2416 (Online)

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Changes in land-use systems such as the introduction of trees on agricultural land can give rise to changes in the physicochemical properties of the soils, also affecting the quantity and quality of organic matter incorporated into the system. The present study assesses humic substances (HS) in the soil such as humic acid (HA) and fulvic acid (FA) by looking at the relationship between the optic densities determined at 465 and 665 nm (E4/E6 ratio). Topsoil samples (0–20 cm) from pine woodlands 60 years of age were compared with agricultural soils of similar age in the central-south region of the Province of Buenos Aires, Argentina. The pH of the topsoil from beneath the pine trees was highly acidic (5.0 vs. 6.2) and a significant increase in the level of organic carbon (OC) was registered. The carbon to nitrogen (C/N) ratio was also higher (by one order of magnitude) beneath the pine trees, although the humification conditions of the soil organic matter (SOM) were good in the soils of both studied land-use systems. The E4/E6 ratio was higher in the HA and FA 2 (second extraction) beneath the pines, indicating a smaller molecular size of the HS bound to the clay minerals. This fact can be attributed to the higher concentration of hydrogen ions beneath the pines and consequently the loss of polyvalent cations, mainly calcium. The most labile organic molecules (FA 1 – first extraction) were of a larger size in soils beneath the pines, most likely owing to a specific characteristic of the Pinus genus, although the fraction in question constitutes a minority fraction among the HS. Clear differences were established between the E4/E6 ratios in HA and FA, making this a highly useful method for determining molecular changes in HS as a result of changes in land use.

KEYWORDS: Fulvic acid, humic acid, pinus afforestation

Cropping Systems: Applications, Management and Impact

Cropping Systems: Applications, Management and Impact

Editors: Johanna G. Hodges

Book Description:

This book provides a discussion on the applications, management and impact of cropping systems.