Nitrogen status in maize grown at different row spacings and nitrogen availability

Barbieri, P. A., Echeverría, H. E., Sainz Rozas, H. R. and Andrade, F. H. 2013. Nitrogen status in maize grown at differentrow spacings and nitrogen availability. Can. J. Plant Sci. 93: 10491058. Improving nitrogen use efficiency (NUE) isimperative to sustainable agriculture. To attain this goal in maize crops (Zea mays L.) there are nitrogen (N) diagnosismethods that enable determination of a crop?s nutritional status by analysis of plant parts. Maize planted in narrow rows(NR) can have increased dry matter (DM), grain yield and accumulated N. However, no reports have been found on theeffect of NR of N in plant diagnosis methods. An experiment was performed over 3 yr to evaluate NR and N fertilizer rateson the N dilution curve, N concentration in grain and chlorophyll content in maize. Treatments consisted of a factorialcombination of row width (70, 52 and 35 cm) and N rate (0 to 180 kg N ha1). The N dilution curves adjusted for fertilizedor control treatments were similar among row spacing. Nitrogen concentration in grain was correlated with relative yield(RY), and similar critical values for N response were similar between row spacings. Leaf chlorophyll content increasedwith N and NR; however, green index (GI) and N sufficiency index (NSI) values were not different between row spacingwhen correlated to RY. These results indicate that response thresholds to N fertilization determined on plant tissue for NRtreatments were similar among row spacings. Thus, there is no need to adjust the response thresholds to N applicationbased on row spacing, as NR did not cause any changes in physiological efficiency (PE) due to the determined proportionalincreases, both in accumulated N in DM and grain yield.Fil: 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; ArgentinaFil: Echeverria, Hernan Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; ArgentinaFil: Sainz Rozas, Hernan Rene. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. 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; ArgentinaFil: Andrade, Fernando Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentin

Using Canopies indices to Quantify the Economic optimum nitrogen rate in Spring Wheat

In-season N applications to spring wheat (Triticum aestivum L.) may increase profits and improve N fertilizer accuracy. The objectives were to develop a calibration tool employing normalized difference vegetative index (NDVI) and SPAD 502 chlorophyll meter (SPAD) measurements for calculating the differential from the economic optimum N rate (dEONR) at growth stages Z22, Z24, and Z31 to Z39 and provide N rate algorithms for use in applying N fertilizer at a variable rate. Sensing was conducted trials over 3 yr encompassing 10 site-years across Southeastern Buenos Aires Province, Argentina. The relationship between sensor indices and dEONR was evaluated by fitting quadratic plateau (QP) regression models. Statistically significant QP models were determined at the Z24, Z31, and Z39 growth stages. Relative SPAD (rSPAD) and relative NDVI (rNDVI) reduced variation and improved the calibration of measured N stress with the dEONR. For Z31 and Z39, the rSPAD had the best goodness of fit statistics when compared to rNDVI [adjusted R2 (adjR2)= 0.67 and 0.57 at Z31 and 0.68 and 0.52 at Z39, respectively]. However, adjustment at Z24 was higher for rNDVI (adjR2 = 0.53 and 0.61 for rSPAD and rNDVI, respectively). A single QP model to estimate the dEONR with 58% confidence was adjusted for the Z31 and Z39 growth stages. This indicates that the same calibration for N rate determination based on rSPAD or rNDVI values can be used during stem elongation in spring wheat. This model can be used as an N rate algorithm for applying N fertilizer in-season.Fil: Reussi Calvo, Nahuel Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sainz Rozas, Hernan Rene. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Diovisalvi, Nadia Rosalia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Water Availability and Row Spacing Effects on Nitrogen Use Efficiency in No-Till Maize

Reduced row spacing has shown to increase nitrogen use efficiency (NUE) in no-till irrigated maize; however available information in rainfed conditions is scarce. The objective was to analyze row spacing effects on NUE under different water and nitrogen (N) regimes. Maize crops were grown at Balcarce, Argentina, during two seasons. Treatments included two water regimes (rainfed and irrigated), two rows spacing (35 and 70 cm) and two N rates (0 and 180 kg N ha-1). Nitrogen rate and narrow rows increased total dry matter (DM), grain yield, and DM and grain N accumulation in both water regimes. In both years and water regimes, narrow rows increased NUE. Physiological efficiency decreased with N rate and was not affected by row spacing. Recovery efficiency (RE) decreased with N rate, and wide rows spacing. Narrow rows effects on RE decreased as N availability increased. Narrow rows increased NUE largely as a result of increased RE. Greater RE for narrow rows treatments was evident since early growth stages (V6). Average two growing seasons, grain yield and NUE response to narrow rows was higher for rainfed condition and/or N deficient crops than maize with high N rate and irrigation. Results shown that narrow rows increased NUE in no-till maize under rainfed conditions.EEA BalcarceFil: Barbieri, Pablo Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina.Fil: Echeverría, Hernán. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina.Fil: Sainz Rozas, Hernán Rene. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Innovación para la Producción Agropecuaria y el Desarrollo Sostenible; Argentina

Alternatives for Nitrogen Diagnosis for Wheat with Different Yield Potentials in the Humid Pampas of Argentina

A correct determination of nitrogen (N) fertilization thresholds in wheat that is based on objective yield produces efficient use of this nutrient. Nitrogen fertilization recommendations for traditional wheat require determination of nitrate (NO3-)-N availability at 60 cm deep at planting time. However, this methodology is complicated, expensive, and time-consuming; thus, the determination of NO3--N level at a lesser depth and at a different time would be desirable. The goals of this work were to determine available N in soil thresholds for traditional and French germplasm wheats and the feasibility of diagnosing N requirements by measuring NO3--N at 40 cm deep, at planting or tillering times, in the southeastern Pampas. The experiments were factorial combinations of N rates and fertilization times (planting and tillering) at different sites and years during 2002-2006. Nitrogen fertilization significantly increased grain yield and protein content. French varieties presented greater grain yield (23%), lower protein content (11%), and greater yield per N unit, indicating greater N-use efficiency (NUE) than traditional varieties. A similar relationship was determined between grain yield and available N at both sampling depths. This might be explained by the strong association between NO3--N content at 60 and 40 cm deep at both sampling dates. Maximum yield and available N determined at 60 or 40 cm soil deep showed that thresholds were lower for tillering than for planting, regardless of the genotype (152 and 174 kg of available N, respectively). Available N thresholds for 95% of maximum yield were less at 0-40 cm deep than at 0-60 cm deep (10 and 14 kg N ha-1 for traditional and French genotypes, respectively). The results of this experiment suggest the possibility of diagnosing N requirements for wheat by measuring NO3--N content at 40 cm deep, instead of the usual 60 cm, for both traditional and French genotypes.Fil: Barbieri, Pablo Andres. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Nitrogen recovery efficiency from urea treated with NSN co-polymer applied to no-till corn

Nitrogen (N) rate increases used by many farmers produce a reduced or null effect on N recovery efficiency (RE) by crops. Therefore, management practices to reduce N losses and increase RE are necessary. Co-polymer maleic itaconic acid (NSN) have become available for use with urea and has shown potential in reducing N losses. The objective of this study was to evaluate the effectiveness of urea treated with NSN on grain yield and RE in a no-till corn. A field experiment was carried out at Balcarce, Argentina over three years, evaluated treatments were urea and urea + NSN at 120 N kg ha− 1, and additional 0 N treatment was included. Urea + NSN was effective to reduce total ammonia volatilization losses, and the average of two years were 1.4 (1.1% to N applied) and 8.7 kg ha− 1 (7.2% to N applied) for urea + NSN and urea, respectively. However, while grain yield and N grain removal were not affected by urea + NSN, the N rate significantly increased grain yield and N grain removal. Nitrogen recovery efficiency was not affected by urea + NSN, RE (average of three years) was 29.0% and 27.8% for urea and urea + NSN, respectively. In conclusion, there was no advantage of using urea treated with NSN in no-till corn overgrain yield, N grain removal, or RE.Fil: Barbieri, Pablo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Sainz Rozas, Hernan Rene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Echeverria, Hernan Eduardo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Phosphorus placement effects on phosphorous recovery efficiency and grain yield of wheat under no-tillage in the Humid Pampas of Argentina

No-till (NT) affects dynamics of phosphorus (P) applied. Wheat response to P fertilization can be affected by available soil P, grain yield, placement, rate, and timing of fertilization. Furthermore, mycorrhizal associations could contribute to improving plant P uptake. Three experiments were used to evaluate P rate (0, 25, and 50 kg P ha−1) and fertilizer placement (broadcasted or deep-banded) effects in NT wheat on P recovery efficiency (PRE) yield and arbuscular mycorrhizal colonization (AMC) which was assessed in one experiment. Fertilization increased dry matter (DM) and accumulated P. Broadcasted P produced lower P accumulation than deep-banded P only at tillering. Phosphorus rate decreased PRE, and placement method did not affect it. Grain yield response was increased by P rate (857 and 1805 kg ha−1 for 25 and 50 kg P ha−1, resp.) and was not affected by placement method (4774 and 5333 kg ha−1 for broadcasted and deep-banded, resp.). Deep-banded P depressed root AMC compared with broadcast applications. Highest AMC in P broadcasted treatments could help to explain the lack of differences between placement methods. These results indicate thatMollisol have low P retention capacity.Therefore, broadcasted P could be used as an alternative of fertilizer management for NT wheat.EEA BalcarceFil: Barbieri, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Covacevich, Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Comparison of methods for determining soil organic carbon

El carbono orgánico total (COT) del suelo por su efecto benéfico sobre las propiedades físicas, químicas y biológicas, es considerado como uno de los principales indicadores de calidad de suelo, por lo que es necesario determinarlo con suficiente exactitud. Para algunos suelos de la Región pampeana y extrapampeana se compararon las técnicas de determinación de COT de Walkley & Black, Walkley & Black modificado y calcinación (LOI) con respecto al método de combustión seca de Dumas, tomado como referencia. Se obtuvo una alta correlación entre las técnicas de determinación de COT (r2 =0,98-0,99). Se verificó el factor de corrección de 1,32, usado habitualmente en la metodología de Walkley & Black para convertir el carbono fácilmente oxidable (CFO) en COT. Se observó que la pendiente de la relación entre la MO determinada por LOI y el COT determinado por el método de Dumas (1,697) no difirió del valor de 1,724 habitualmente empleado para la conversión de COT a MO. La metodología de Dumas mostró mayor veracidad y precisión respecto de las demás técnicas de determinación de COT.Beneficial effects of soil organic carbon (COT) on physical, chemical and biological properties, is considered an indicator of soil quality, so it is necessary to determine it accurately. Walkley & Black, modified Walkley & Black and ignition (LOI) with respect to the dry combustion method of Dumas were compared for some soils of the Pampean and extrapampean region. A high correlation between COT determination techniques (r2 = 0.98-0.99) was obtained. Correction factor of 1.32, commonly used in the methodology of Walkley & Black to convert readily oxidizable carbon (CFO) in COT was verified. It was observed that the slope of the relationship between the COT determined by LOI and COT determined by the Dumas method (1.697) did not differ in value from 1,724, routinely used for the conversion of COT a MO. Dumas methodology showed greater accuracy and precision with respect to other techniques for determination of COT.Fil: Eyherabide, Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Barbieri, Pablo Andres. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Inclusion of Cover Crops in Cropping Sequences with Soybean Predominance in the Southeast of the Humid Argentine Pampa

Abstract: The incorporation of a cover crop (CC) may be an alternative to increase soil carbon (C) and nitrogen (N) supply in crop sequences with a high frequency of soybean. The aims of this study were (i) to determine shoot biomass production, C and N contents in the CC under two N additions, (ii) to evaluate the effect on soybean grain yield of including a CC, and (iii) to evaluate the water productivity of the crop sequences. Crops were evaluated during three growing seasons of a long-term field trial under no tillage on Typic Argiudoll in Balcarce, Buenos Aires, Argentina. Mean CC shoot biomass was 6.6 Mg ha-1 yr-1 for N-fertilized and 5.2 Mg ha-1 yr-1 for non-fertilized treatments. Mean C and N accumulation in the CC shoot biomass were 2.8 Mg C ha-1 yr-1 and 131 kg N ha-1 yr-1 in N-fertilized treatments, and 2.3 Mg C ha-1 yr-1 and 67 kg N ha-1 yr-1 in nonfertilized treatments. Soybean grain yield ranged from 2.4 to 4.3 Mg ha-1. In two out of the three growing seasons, soybean grain yield was greater (p<0.05) for crop sequences that included a CC. Water productivity was higher (p<0.05) in crop sequences with a CC and even higher when they were N-fertilized. The inclusion of a CC preceding soybean in crop sequences is an alternative to improve soil C and N budgets and would be a promising strategy to increase productivity and cropping system sustainability in this region.Fil: Martínez, Juan Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. 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; ArgentinaFil: Barbieri, Pablo Andres. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Sainz Rozas, Hernan Rene. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Echeverria, Hernan Eduardo. 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; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Dosis óptima económica de fósforo en el cultivo de papa en el sudeste bonaerense

Asegurar una buena disponibilidad de fósforo (P) para el cultivo de papa, es tan importante como ajustar la estrategia de fertilización para producir el máximo rendimiento con la mayor eficiencia económica. El Avail, aditivo que puede aplicase como recubrimiento de fertilizantes fodforados, ha demostrado aumentar la eficiencia de uso en diversos cultivos, sin resultados consistentes en papa.To ensure the phosphorus (P) availability in potato crop is as important as to adjust the fertilization strategy to achieve maximum yield with the greatest economic efficiency. Avail®, which is an additive that can be used to coat phosphorus fertilizers, was proven to increase P fertilizer efficiency in various crops, but without consistent results in potato. For potato crops in the Southeastern Buenos Aires, the objectives of this research were: 1- to compare potato yield at different rates of calcium triple superphosphate (TSP) with and without Avail® addition and, 2- to establish the phosphorus fertilization rate that produces the maximum economic benefit (DOE). Information of nine P fertilization trials (2005-14) were used. Bray1 and Mehlich3 tests were applied to soil samples taken before crop planting and total yield was determined. The DOE were calculated for different fertilizer/tuber price relationships. Fertilization increased yields with average values of 44 Mg ha-1 for the unfertilized plots and 52-69 Mg ha-1 for the fertilized treatments. There were no significant yield differences due to the use of different P sources (TSP or TSP +Avail®), for any of the tested rates. This result was consistent across all trials despite having different extractable P contents before planting. Determined DOE for Bray1 or Mehlich3 were similar (R2=0, 8). For both extractants, the DOE decreased with increasing P availability, specifically: DOE P (kg ha-1) = 176 - 5*Bray1; 216 - 6*Mehlich3. Even though both soil P availability and price relationships affected the DOE, the first was the determining factor to define the suitable phosphorus fertilizer rate for cost-effective production of potato crops.EEA BalcarceFil: Zamuner, Ester Cristina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Lloveras, Jaume. University of Lleida. Agrotecnio Center; EspañaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce-Unidad Integrada-Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Chemical characteristics as determinants of arbuscular mycotrophic ability of agricultural and pristine soils from buenos aires (Argentina)

Los suelos de la Provincia de Buenos Aires (Argentina) presentan muy buenas características físicas y químicas para la producción agrícola, así como elevada diversidad microbiana. Sin embargo la continua explotación agrícola del suelo, con permanente extracción de nutrientes, aceleró su degradación, afectó su fertilidad natural y las poblaciones microbianas potencialmente benéficas como los hongos formadores de micorrizas arbusculares (MA), aspecto que ha sido poco explorado. El objetivo ha sido identificar cambios en el contenido de nutrientes en suelos sometidos a manejo agrícola contrastante que podrían incidir en la capacidad micotrófica de los hongos MA. Se colectaron muestras de suelo de 29 sitios de la Provincia de Buenos Aires bajo manejo agrícola, o sin uso (prístino). Se determinaron las características químicas (CIC, Fe, Mn, Cu, Zn, B, P-Bray, CO y pH), así como el grado de micorrización nativa, luego de 12 semanas desde la instalación de cultivos trampa. Los valores de las características químicas fueron, en general, mayores para los sitios prístinos que para los que estuvieron bajo agricultura. Sin embargo, la intensidad de micorrización no fue significativamente diferente en relación al manejo del suelo. El análisis de componentes principales permitió agrupar por una parte los sitios que se encontraban bajo agricultura y por otra parte los sitios prístinos. El contenido de P disponible en el suelo, juntamente con el contenido de Fe parecerían ser los principales depresores de la capacidad micotrófica de los suelos analizados, particularmente en condiciones de moderado-bajo contenido de Carbono Orgánico.The soils of Buenos Aires Province (Argentina) have very good physical and chemical properties for agricultural production, and also a high microbial diversity. However, the continuous cropping of agricultural soils with a high nutrient removal rate has accelerated its degradation. Consequently, the soils’ natural fertility and the beneficial microbial populations such as arbuscular mycorrhizal fungi (AMF) could be affected. The objective of this study was to identify changes in the nutrient content in soils under contrasting managements (agricultural vs. pristine) that could influence the mycotrophic ability of AMF. Soil samples were collected from 29 agricultural sites in Buenos Aires Province under cropped and non-cropped (pristine) systems. Chemical characteristics were determined (CIC, Fe, Mn, Cu, Zn, B, P-Bray, CO and pH) in composed samples collected from each field. Mycotrophic ability was estimated by assessing the degree of root colonization by native mycorrhiza in trap crops after 12 weeks of sowing. The values of chemical properties were generally higher for pristine sites than for agricultural plots. However, the mycotrophic ability did not differ between cropped and pristine soils. The principal component analysis allowed grouping field sites under agriculture or pristine conditions. Soil available P content, together with Fe and to a lesser extent Mn content- seemed to depress the mycotrophic ability of the analyzed soil, particularly under moderate to low organic carbon contents conditions.Fil: Covacevich, Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Eyherabide, Mercedes. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Sainz Rozas, Hernan Rene. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria; Argentina. Universidad Nacional de Mar del Plata; Argentin