Available zinc levels in soils of Argentina

Adequate grain zinc (Zn) concentration is important because of its influence on human health. The Argentina Pampas region (APR) provides between 86% and 90% of total grain exports by the country. Soils of the Argentina Pampas region had high fertility under pristine condition but intensification of agriculture, increasing grain yields, and poor or no Zn fertilization could reduce soil available Zn. The objectives of this work were to determine the distribution of available Zn in agricultural and pristine soils of the Argentina Pampas region and its relationship with some chemical characteristics. Soil samples (0-20 cm depth) were collected and georeferenced (approximately 550 for each condition), and soil organic matter, pH, extractable phosphorus, cation exchange capacity, and available Zn by extraction with diethylenetriaminepentaacetic acid (DTPA-Zn) were measured. For geostatistical analysis, indicator kriging (non-parametric method) was utilized as interpolation method. Agriculture decreased soil organic matter, pH, extractable phosphorus and DTPA-Zn (26.9, 4.6, 57.8 and 69.5%, respectively). Relative decrease of DTPA-Zn was only significantly associated with the relative decrease of soil organic matter, although this association was low (r=0.41). Regionally, the DTPA-Zn distribution was very heterogeneous and soil organic matter, pH, extractable phosphorus and cation exchange capacity did not adequately predicted soil DTPA-Zn concentrations (r2=0.16 to 0.26). Agricultural soils of northern, northwestern and southwestern APR (approximately 12,150,000 ha) showed DTPA-Zn values below 1 mg kg-1 , and therefore would present some degree of Zn deficiency for sensitive crops.Fil: Sainz Rozas, Hernan Rene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Puricelli, Marino Marcelo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Eyherabide, Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Barbieri, Pablo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Reussi Calvo, Nahuel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Laboratorio Ferilab; ArgentinaFil: Martinez, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Maize nitrogen management in soils with influencing water tables within optimum depth

The central temperate Argentinean region is currently affected by rising water tables, allowing higher and more stable maize yields (Zea mays L) when they fluctuate within optimum depth. However, limited information was available for optimizing N management in these environments. Yield response to N rates was explored in soils with influencing groundwater (always less than 3.5 m depth), and different environment and management variables were examined to help explain differential yield responses across sites. A total of 15 rainfed experiments (site × year combinations) were conducted with five N rates (0 to 240 kg N ha−1) tested at two different timings (sowing and V7) in a factorial design. A consistent yield response to N rate was evident, increasing yields from 2300 to 6900 kg ha−1 across sites. Yields at maximum N levels ranged from 13700 to 16900 kg ha−1. Fertilization timing had a minor and inconsistent effect on yield across sites. At a maize grain:fertilizer N price ratio of 10, the economically optimal N rate ranged from 117 and 206 kg N ha−1. Soil N‐NO3 at sowing, previous crop, and apparent‐INS (apparent‐indigenous N supply) helped explain differential yield responses across sites, and response models for obtaining economic optimum rates considering the influence of these variables are provided. These results highlight the relevance of N rate, rather than timing, as a critical crop management decision in environments with high water availability and yield.EEA OliverosFil: Ruiz, Alejo. Asociación Argentina de Productores en Siembra Directa; ArgentinaFil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros; ArgentinaFil: Gambin, Brenda L. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; ArgentinaFil: Borrás, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Investigaciones en Ciencias Agrarias de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias. Instituto de Investigaciones en Ciencias Agrarias de Rosario; Argentin

A meta-analysis of hairy vetch as a previous cover crop for maize

Background: The use of hairy vetch (Vicia villosa Roth.) as cover crop is increasing worldwide. Hairy vetch can contribute as a nitrogen (N) source with potential to impact subsequent high N demanding cereals such as maize (Zea mays L.). Contrasting literature results emphasize the need for a global synthesis analysis to quantify changes in maize yield after hairy vetch. Objectives: A meta-analysis was conducted to i) quantify maize yield response to hairy vetch as previous crop, ii) explore hairy vetch influence on fertilized and non-N fertilized maize yields, and iii) assess the tillage and environment factors on maize yield response to hairy vetch. Methods: The global systematic search yielded 23 publications selected by the following criteria, i) hairy vetch dry matter at the end of the season, ii) maize grain yield, and iii) experimental design with (Mzhv) and without (Mzcontrol) hairy vetch treatments. Information such as N fertilization for maize, N accumulation in hairy vetch, organic matter, and tillage before maize sowing were recorded. Hairy vetch effects (effect size) were expressed as a ratio (percentage of grain yield variation in Mzhv/Mzcontrol). Results: Under non-N fertilization (n = 9), results revealed hairy vetch had mostly a positive effect, ranging from 13 to 45% (n = 6). In contrast, N-fertilized maize (n = 20) showed a high chance of neutral effects (n = 12), moderate probability of positive yield impact (7 to 38%, n = 6), and a low likelihood of negative effects (−32 and −17%, n = 2). Notably, maize yields improved by 21–25% when the N accumulation in hairy vetch ranged from 95 to 150 kg ha−1 and N rate from 0 to 120 kg ha−1. Non-N-fertilized maize exhibited a 14% increase in response in no-till systems and a 31% increase with conventional tillage. Conclusion: This study summarizes potential benefits of hairy vetch preceding maize. Yet, the heterogeneous outcomes deserve further exploration in terms of environment and management factors

Nitrogen mineralized in anaerobiosis as indicator of soil aggregate stability

Monitoring soil health status is imperative to pursue sustainable agriculture. Aggregate stability (AS) is fundamental to define several soil functions and, therefore, physical soil health. The objectives of thisworkwere to (i) evaluate the effect of contrasting cropping systems on AS, soil (SOC) and particulate (POC) organic carbon, and anaerobic nitrogen (AN) both in bulk soil and in macroaggregates (MA), and (ii) assess the relationship between AS and AN both in bulk soil and in MA to facilitate soil physical health monitoring. Aggregate stability, AN, SOC and POC were evaluated at three depths (0–5, 5–20, and 0–20 cm) in a Mollisol of the Southeastern Argentinean Pampas under a long-term experiment of cropping systems (crop-pasture rotations under conventional tillage [CT] and no-tillage [NT]). Bulk-soil SOC and POC contents and AN showed the effect of cropping systems, especially the effect of crop-pasture rotation and at 0–5 cm depth. However, NT did not lead to SOC sequestration except at 0–5 cm depth. In turn, pastures in the rotation and NT improved AS. Bulk-soil AN explained 75, 41, and 71% of AS at 0–5, 5–20, and 0–20 cm depths, respectively, and provides an indication of AS status. Instead, AN in MA did not explain bulk-soil AS changes as much as bulk-soil AN, except at 0–5 cm depth. Therefore, it is not worth determining AN in MA. However, routine bulk-soil AN determination at 0–20 cm depth by producers to diagnose nitrogen soil fertility would also provide an additional valuable indication of AS status