Early breeding of yearling beef heifers at the Flooding Pampas:scientific support of current practices. A review

La producción de carne en los rodeos de cría vacuna en la Pampa Inundable se mantiene desde al menos cinco décadas en valores de 70 kg ha-1 año-1. La aplicación de conocimientos científicos internacionales y nacionales permitirían duplicarla sin prácticamente cambiar los pastizales existentes. El servicio precoz de vaquillonas es una técnica de alto impacto en la eficiencia reproductiva de los vacunos. Se revisó exhaustivamente la información científica publicada en Argentina sobre los factores forrajeros, nutricionales y reproductivos que influyen en el manejo del servicio precoz de vaquillonas en la Pampa Inundable. También se aportaron conocimientos internacionales que enriquecieron, por su calidad y cantidad, esta revisión. Se discuten los fundamentos biológicos de las prácticas de manejo de servicio precoz y refugo de vacas y dos técnicas de selección de reproductores: área pélvica y circunferencia escrotal, de amplio uso a nivel nacional. Se encontró falta de evidencias científicas concluyentes. La investigación local debiera ser impulsada para ajustar la información internacional a las condiciones nutricionales de los pastizales, las condiciones de manejo y el biotipo vacuno predominantes en la región.Cow-calf annual beef production in the Flooding Pampas has been sustained around 70 kg ha during the last five-1decades. Integrating international and national knowledge could be applied to double the beef production per hectareusing the temperate rangelands of this region. The early breeding of beef heifers has a high impact on reproductiveefficiency. National scientific publications about the nutritional and reproductive management at the Flooding Pampaswere particularlyreviewed.The main purpose ofthis review was to considerthe biological basis of the early breeding andthe cullingofopencowsat pregnancy testsandalso theanalysis of two breeding selection technics widely promoted inArgentina: scrotal circumference on bulls and pelvic area on heifers. Conclusive evidence was not found. Local researchshould be enhanced to adjust the international knowledge to Flooding Pampa’s environmental and managementconditionsFil: Cauhepe, Miguel Alfredo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Cafaro la Menza, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Insufficient nitrogen supply from symbiotic fixation reduces seasonal crop growth and nitrogen mobilization to seed in highly productive soybean crops

Nitrogen (N) supply can limit the yields of soybean [Glycine max (L.) Merr.] in highly productive environments. To explore the physiological mechanisms underlying this limitation, seasonal changes in N dynamics, aboveground dry matter (ADM) accumulation, leaf area index (LAI) and fraction of absorbed radiation (fAPAR) were compared in crops relying only on biological N2 fixation and available soil N (zero-N treatment) versus crops receiving N fertilizer (full-N treatment). Experiments were conducted in seven high-yield environments without water limitation, where crops received optimal management. In the zero-N treatment, biological N2 fixation was not sufficient to meet the N demand of the growing crop from early in the season up to beginning of seed filling. As a result, crop LAI, growth, N accumulation, radiation-use efficiency and fAPAR were consistently higher in the full-N than in the zero-N treatment, leading to improved seed set and yield. Similarly, plants in the full-N treatment had heavier seeds with higher N concentration because of greater N mobilization from vegetative organs to seeds. Future yield gains in high-yield soybean production systems will require an increase in biological N2 fixation, greater supply of N from soil or fertilizer, or alleviation of the trade-off between these two sources of N in order to meet the plant demand.Fil: Cafaro la Menza, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Nebraska - Lincoln; Estados UnidosFil: Monzon, Juan Pablo. Universidad de Nebraska - Lincoln; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Lindquist, John L.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Arkebauer, Timothy J.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Knops, Johannes M. H.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Unkovich, Murray. University of Adelaide; AustraliaFil: Specht, James E.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Grassini, Patricio. Universidad de Nebraska - Lincoln; Estados Unido

Mejora en la productividad de lechuga por aplicación de compost de cama de pollo

PosterLa cama de pollo es ampliamente utilizada en cultivos hortícolas del Cinturón Hortícola de Mar del Plata. La práctica más común es aplicar la cama de pollo directamente al suelo, sin ningún tipo de tratamiento previo, salvo el apilamiento cercano al lote. Al utilizar la cama de pollo sin ningún tratamiento previo, no se cuenta con un producto estable, maduro e higienizado, ni con información de base sobre la cantidad de nutrientes que se están aplicando al suelo, su biodisponibilidad, ni tampoco sobre la presencia de microorganismos o sustancias indeseadas que puedan perjudicar la salud humana y del ambiente. El compostaje se presenta como una alternativa para transformar la cama de pollo en un subproducto con valor agregado y libre de sustancias nocivas. En este trabajo se evaluaron distintas enmiendas de suelo provenientes de cama de pollo compostada y sin compostar en un cultivo a campo de lechuga criolla (Lactuca sativa L.). Se utilizaron tres tipos de compost de cama de pollo: C1: compostaje pasivo (sin aireación), C2: compostaje con aireación (volteos periódicos), C3: compostaje con aireación y agregado de una fuente extra de carbono para iniciar el proceso con una relación C:N óptima (25:1). Los tratamientos fueron T1: control (sin agregado de enmienda ni fertilizante); T2: compost C3; T3: compost C2; T4: compost C1; T5: cama de pollo sin compostar. En T2, T3, T4 y T5 se aplicó por única vez la misma dosis de enmienda de 40 tn/ha. Se midieron distintas propiedades fisicoquímicas del suelo (CE, pH, materia orgánica (MO), N-NH4+, N-NO3, P-Bray) al inicio y final del experimento (39 días luego de la aplicación). Al momento de cosecha, se midió el rendimiento en biomasa del cultivo, biomasa radicular, área foliar y contenido de N-NO3 en hoja. El agregado de compost C (CUAL?) y de cama de pollo cruda aumentó significativamente la concentración de P-Bray comparado con el suelo sin tratar y los compost A y B. El suelo control presentó una CE significativamente más baja que los suelos que recibieron compost y cama de pollo cruda. Al finalizar el ensayo, se observó un aumento significativo en el contenido de MO en los tratamientos T4 y T5 con respecto a los demás tratamientos. En el cultivo, el mayor rendimiento de biomasa área fresca se obtuvo con los tratamientos T2 y T3 (44 y 39 tn/ha, respectivamente). Tanto el tratamiento control sin aplicación de enmienda como el T4 y T5, compost sin airear y cama de pollo sin compostar, rindieron en promedio 30 tn/ha. Por lo tanto, el uso de cama de pollo compostada aireada como enmienda produce un aumento en el rendimiento del 40%. Respecto al peso seco, se obtuvo un mayor peso en las lechugas del T2, mientras que el menor valor se obtuvo para el tratamiento T5. Estos resultados indican que la cama de pollo cruda podría tener un efecto inhibitorio en el crecimiento de la lechuga, por el posible contenido de sustancias fitotóxicas. Se espera fomentar la implementación del compostaje de los desechos avícolas para su utilización como enmienda del suelo, en concordancia a lo establecido por el marco de las Buenas Prácticas Agrícolas en horticultura, para mejorar no solo el rendimiento de los cultivos, sino también la calidad de los suelos.EEA BalcarceFil: Okada, Elena. 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: Carciochi, Walter. 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: Carciochi Walter. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Pérez, Débora. 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: Cafaro La Menza; Nicolás. 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: Adlercreutz, Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA) Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Mar del Plata; Argentina.Fil: Hernandez Guijarro, Keren. 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: Young, Brian. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; Argentina.Fil: Rizzo, Pedro. Instituto Nacional de Tecnología Agropecuaria (INTA) Estación Experimental Agropecuaria Mendoza; Argentina

Is soybean yield limited by nitrogen supply?

As soybean yield continues to increase, it seems critical to know if there is a yield level at which potential contribution of indigenous nitrogen (N) sources (N fixation and soil mineralization) becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. We have hypothesized that, in absence of other limiting factors, degree of N limitation increases with increasing yield potential (Yp) of the production environment. To test this hypothesis, we developed a novel protocol to ensure an ample N supply during the entire crop season (full-N treatment). That protocol was applied to field-grown irrigated soybean in Balcarce (Argentina) and Nebraska (USA), where measured full-N seed yields were ±15% of their simulated Yp in 92% of the cases. The combination of locations, years, sowing dates, and N treatments resulted in a wide range of seed yields, from 2.5 to 6.5 Mg ha−1. Overall, full-N seed yield averaged 11% higher than seed yield without N addition (zero-N). However, magnitude of yield difference between full-N and zero-N depended upon Yp, ranging from no detectable yield difference in low-Yp (ca. 2.5 Mg ha−1) to up to 900 kg ha−1 in high-Yp environments (ca. 6 Mg ha−1). Seed yield differences were associated with higher aboveground dry matter, seed number, and seed weight in the full-N versus zero-N treatments. Seed protein (but not oil) concentration was higher in the full-N treatment, and both protein and oil yields were higher in the full-N versus zero-N treatments. Findings from this study indicate that (i) N limits soybean seed yield (as well as protein yield, and oil yield) in environments with high Yp, where indigenous N sources seem insufficient to fully satisfy crop N requirements, and (ii) yield response to N fertilizer can occur above a 2.5 Mg ha−1 Yp threshold and has an upper limit of 250 kg seed per Mg increase in Yp.Fil: Cafaro la Menza, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. University of Nebraska; Estados UnidosFil: Monzon, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Specht, James E.. University of Nebraska; Estados UnidosFil: Grassini, Patricio. University of Nebraska; Estados Unido

Soybean

Soybean is the major source of vegetable protein in the world. It is produced over a wide range of latitudes, from the Canadian prairies and Northern Great Plains in the USA to tropical areas in the Brazilian Cerrados. This chapter evaluates the environmental (E) and genetic (G) factors regulating soybean development, growth, seed yield, and seed constituents, as influenced by management (M) practices as well. The chapter focuses on three major soybean-producing regions of the world (Corn Belt in USA, Brazilian Cerrados, and Argentinean Pampas), providing examples about how G × E × M interactions are exploited for regional and local adaptation. Opportunities for yield improvement and future research are highlighted.Fil: Grassini, Patricio. Universidad de Nebraska - Lincoln; Estados UnidosFil: Cafaro la Menza, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad de Nebraska - Lincoln; Estados UnidosFil: Rattalino Edreira, Juan Ignacio. Universidad de Nebraska - Lincoln; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Monzon, Juan Pablo. Universidad de Nebraska - Lincoln; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Tenorio, Fatima A.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Specht. James E.. Universidad de Nebraska - Lincoln; Estados Unido

Nitrogen limitation in high-yield soybean: Seed yield, N accumulation, and N-use efficiency

Recent reviews about soybean nitrogen (N)requirement have speculated about a possible N limitation in high-yield environments (>4.5 Mg ha−1). However, these studies did not provide definitive experimental data to test that hypothesis and results from the literature are conflicting. To fill this knowledge gap, we evaluated N limitation across 13 high-yield soybean environments in Argentina and USA. Each experiment included a ‘zero-N’ treatment, which forced the crop to rely on biological N2 fixation and indigenous soil N, and a ‘full-N’ treatment, which provided an ample fertilizer N supply during the entire crop cycle based on site-specific yield potential. Accumulated N in aboveground dry matter (ADM)measured in a N-omission maize plot grown adjacent to the soybean experiments was used to determine indigenous soil N supply. Soybean seed yield, protein and oil concentration, ADM, harvest index (HI), accumulated N in ADM, N harvest index (NHI), and seed N were measured in both treatments at physiological maturity. A simple conceptual framework relating ADM with accumulated N was used to assess treatment differences in ADM, accumulated N, and N-use efficiency (NUE). To account for treatment differences in seed biomass composition, mass-based ADM was expressed in glucose equivalents (ADMe). Seed yield ranged from 4.6 to 6.7 Mg ha−1 (full-N)and 4 to 5.8 Mg ha−1 (zero-N), with the full-N treatment averaging 12% (0.6 Mg ha−1)and 3% (9 g kg−1)higher seed yield and protein concentration, respectively. The full-N treatment exhibited 18% (70 kg N ha−1)and 14% (1.6 Mg ha−1)greater accumulated N and ADM, respectively, compared with the zero N treatment, without changes in HI and NHI, but slightly lower NUE (29 versus 30 kg ADM kg−1 N in full and zero-N, respectively). However, NUE differences between treatments became indistinguishable when ADM was expressed as ADMe (45 kg glucose kg−1 N). The (full-N minus zero-N)seed yield difference and the indigenous soil N supply were negatively associated. This research documented (i)the existence of N limitation in high-yield soybean, (ii)that seed yield and protein concentration increases were physiologically associated with changes in accumulated N (but not in NUE and/or NHI), and (iii)that the degree of N limitation is modulated by indigenous soil N supply. Findings from this study can serve as a basis to identify environments with the largest N limitation and thus guide N management in soybean.Fil: Cafaro la Menza, Nicolás. Universidad de Nebraska - Lincoln; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Monzon, Juan Pablo. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Specht, James E.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Lindquist, John L.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Arkebauer, Timothy J.. Universidad de Nebraska - Lincoln; Estados UnidosFil: Graef, George. Universidad de Nebraska - Lincoln; Estados UnidosFil: Grassini, Patricio. Universidad de Nebraska - Lincoln; Estados Unido

Critical period for seed number determination in soybean as determined by crop growth rate, duration, and dry matter accumulation

Seed number (SN) is positively associated with aboveground dry matter (ADM) accumulation in most crop species. In soybean, there are discrepancies among studies relative to the start and end of the critical period for seed number determination. The objective of this study was to more precisely identify those two stages. To do so, we followed two approaches: (i) analyses of experimental data where differences in SN occurred as a result of variation in crop growth due to weather and management practices and (ii) review of published experiments where soybean was subjected to artificial stresses during specific crop phases. Following the first approach, we analyzed the relationships between SN versus ADM accumulation and its components, crop growth rate (CGR) and duration, for different reproductive phases using data from experiments that portrayed a wide range of environments and management practices. In the second approach, we compared SN values in stressed versus non-stressed treatments. Accumulated ADM during the R3 to R6 phase explained ca. 70 % of the variation in SN across experiments. The CGR during R3-R6 was also a good predictor of SN, but it had lower explanatory power compared with accumulated ADM, because CGR did not account for changes in duration of critical period across experiments. Review of published data, wherein soybean crops were subjected to artificial stresses during different reproductive phases, confirmed that the R3-R6 phase is a critical phase for SN determination in soybean. Key findings of this study were: (i) critical period for SN determination in soybean occurs during the R3-R6 phase and (ii) accumulated ADM during the critical period is a better predictor of SN compared with CGR because it accounts for differences in the duration of the critical period as a result of weather and management.EEA BalcarceFil: Monzón, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. University of Nebraska-Lincoln. Department of Agronomy and Horticulture; Estados Unidos.Fil: Cafaro La Menza, Nicolás. University of Nebraska-Lincoln. Department of Agronomy and Horticulture; Estados Unidos.Fil: Cerrudo, Aníbal Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Cánepa, Matías. Actividad privada; Argentina.Fil: Rattalino Edreiraa, Juan Ignacio. University of Nebraska-Lincoln. Department of Agronomy and Horticulture; Estados Unidos.Fil: Spechta, James. University of Nebraska-Lincoln. Department of Agronomy and Horticulture; Estados Unidos.Fil: Andrade, Fernando Héctor. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Grassinia, Patricio. University of Nebraska-Lincoln. Department of Agronomy and Horticulture; Estados Unidos

Analysis of factors controlling maize yield response to hairy vetch and to nitrogen fertilization after hairy vetch

Context or problem: Several agricultural producers around the world are adopting hairy vetch (HV) (Vicia villosa Roth) inclusion in the crop sequence before maize (Zea mays L.). To date, it is not clear which factors control maize yield response to HV and to nitrogen (N) fertilization in HV-maize sequences. Objective or research question: We aimed to i) explore the variability of maize grain yield response to HV and to N fertilization (after HV) and ii) analyze the factors that define the mentioned variability. Methods: We conducted 25 field studies in the southeastern Argentinean Pampas, exploring a wide range of conditions related to HV management and edaphoclimatic properties. We evaluated four treatments resulting from the combination of two preceding conditions, i) HV and ii) bare fallow (BF), and two situations of N fertilization on maize i) with N and ii) without N. Results: We observed that, without N fertilization, maize yield significantly increased by 1846 kg ha−1 due to HV, and the response was significant in 52% of the studies. Low-yield environments exhibited a greater yield response to HV than high-yield environments (2792 vs. 989 kg ha−1). Nitrogen supply from HV was the main factor determining variations in grain yield response to HV, although factors other than N (e.g., water availability, changes in soil physical and biological properties) presented a significant effect (avg. 366 kg ha−1). Specifically, the N supply from HV and soil N availability explained maize yield response to HV. We calibrated and validated a model from these variables that explained 61% of the variability in yield response to HV. We also observed that N fertilization after HV increased maize yield, on average, by 1301 kg ha−1 (significant in 36% of the sites), which was almost half of the response to N fertilization after BF (avg. 2782 kg ha−1, significant in 68% of the sites). Maize yield response to N after HV was explained by both the maize N demand and the N supply from HV. Conclusions: Nitrogen supply from HV and soil N availability defined maize grain yield response to HV. Including HV in crop sequences before maize reduced its fertilizer-N requirement. Maize N demand and N supplied from HV explained the grain yield response to fertilizer-N. Implications or significance: The information and models provided will allow producers to assess the convenience of including HV before maize in the crop sequence and to adjust N fertilization rates, avoiding yield penalties and negative environmental externalities.Fil: Carciochi, Walter Daniel. 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; ArgentinaFil: Cafaro la Menza, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Crespo, Cecilia. 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; ArgentinaFil: Dominguez, Germán. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Rodríguez, María Pía. 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; ArgentinaFil: Reussi Calvo, Nahuel Ignacio. 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; ArgentinaFil: Wyngaard, Nicolás. 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; ArgentinaFil: Sainz Rozas, Hernan Rene. 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; ArgentinaFil: Studdert, Guillermo Alberto. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Barbieri, Pablo Andres. 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; Argentin