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

Catch crops in the Argentinean Pampas: a synthesis-analysis on nutrient characteristics and their implications for a sustainable agriculture

Catch crops (CCs) are crops that grow between two cash crops, accumulating nutrients in their biomass and later releasing them through the decomposition of their residues. To our knowledge, no study has compared the nutrient-related traits of different CCs species. This comparison is essential for understanding the possible roles of CCs in agroecosystems and for optimizing adjustments of fertilizer rates. This study aims to: i) synthesize characteristics of the CCs, such as aboveground dry matter accumulation, nutrient [carbon (C), nitrogen (N), sulfur (S), and phosphorus (P)] concentration and accumulation, and C:nutrient ratios, ii) explore factors defining the mentioned characteristics, and iii) discuss their implications on the ecosystem services provided. By analyzing data from 52 studies, (98 site-years) in the Argentinean Pampas, we observed that grasses (excluding ryegrass) accumulated the greatest aboveground dry matter (6.08 ± 0.22 t ha-1, mean ± SE) and C (2.60 ± 0.13 t ha-1), making them suitable for protecting the soil surface from erosion, suppressing weeds, and improving C balances. Conversely, vetch accumulated the highest nutrient content (118 ± 5.3, 15 ± 1.5, and 14 ± 1.2 kg ha-1 for N, S, and P, respectively) with the lowest C:nutrient ratio (means of 15:1, 152:1, and 147:1 for N, S, and P, respectively), making it a suitable choice for recycling nutrients and providing extra N. Mixtures presented intermediate characteristics between the monocultures, allowing a balanced provision of the mentioned ecosystem services. Furthermore, the results showed that dry matter accumulation affected the nutrient-related traits analyzed, and it was related to different factors, such as CCs sowing and termination dates or precipitation. The analysis highlights the importance of selecting CCs species based on the desired ecosystem service and provides valuable information for producers as well as for modeling C balances and nutrient cycling

Soybean seed protein concentration is limited by nitrogen supply in tropical and subtropical environments in Brazil

Soybean production contributes to ca. 60% of global plant-based protein used for food and feed. Brazil is the largest soybean producer and exporter, with 60% from tropical and 40% from subtropical environments. Nitrogen (N) can play an essential role in the storage of proteins in seeds; thus, it could be a key factor in increasing the quantity and quality of seeds in high-yielding soybean crops. Unlike in temperate environments, there is a gap of knowledge on whether soybean grown under tropical and subtropical climates are limited by N-fertilization to sustain the seed yield increase without detriments in seed protein concentration. This study aimed to evaluate the effect of N-fertilization on soybean seed yield, protein, and oil concentrations in tropical and subtropical environments in Brazil, thus contributing to agricultural intensification procedures and food security studies. Two levels of N-fertilization (0 and 1000 ka/ha) were tested across 11 tropical or subtropical environments. The range of latitudes explored here was from 12º S to 29º S, representing the major soybean-producing regions in Brazil either under rainfed or irrigated conditions. We found that seed yield responses to N-fertilization were significant (in some environments under rainfed with an average increase of 7%) or not significant (in irrigated). Seed protein increases due to improved N-fertilization (on average 4% for irrigated and 12% for rainfed conditions) were much higher than previous reports from temperate environments. Regardless of N supply and water deficit, there was a trend of seed protein and oil concentration increasing toward lower latitudes

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) accumula- tion, 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 allevia- tion of the trade-off between these two sources of N in order to meet the plant demand

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

Macro and Micro-Nutrient Accumulation and Partitioning in Soybean Affected by Water and Nitrogen Supply

This study aimed to investigate the influence of water availability and nitrogen fertilization on plant growth, nutrient dynamics, and variables related to soybean crop yield. Trials were performed in Teresina, Piauí, Brazil, using randomized blocks in a split-split plot arrangement. The plots corresponded to water regimes (full and deficient), the split plots to N fertilization (0 and 1000 kg ha-1 N-urea), and the split-split plots to harvest times of soybean plants (16, 23, 30, 37, 44, 58, 65, 79 and 86 days after emergence), with three replicates. In general, the accumulation and partitioning of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S), copper (Cu), iron (Fe), manganese (Mn), zinc (Zn) and boron (B) were decreased in plants subjected to water deficit and without N fertilization. Although nitrogen fertilization promoted elevated N accumulation in tissues, it did not result in any significant yield gain, and the highest seed yields were found in plants under full irrigation, regardless of N supplementation. However, deficient irrigation decreased the seed oil content of N-fertilized plants. In conclusion, N fertilization is critical for nutrient homeostasis, and water availability impairs biomass and nutrient accumulation, thereby limiting soybean yield performance

Understanding Nitrogen Limitation In Soybean

Meeting soybean demand on existing cropland area for a global population of 9.7 billion people by the year 2050 requires narrowing the existing gap between average producer yield and yield potential. Soybean relies on two sources on nitrogen (N): biological N2 fixation and indigenous soil N 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 sources and fixation becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. This study evaluated N limitation across 29 high-yield soybean environments in Argentina and Nebraska from 2015 to 2017. Each environment 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 novel protocol developed also in this study. Seed yield and protein concentration in full N were 11% and 3% higher than zero-N, respectively. The magnitude of the difference depended upon the yield level of the production environment, ranging from 0 kg ha-1 at 2.5 Mg ha-1 up to 900 kg ha-1 at 6 Mg ha-1. Seed yield responses were directly related with increases in accumulated N in aboveground biomass (70 kg N ha-1), without changes in nitrogen use efficiency. The N limitation was mitigated in environments with large contribution of indigenous soil N supply. The maximum rates of N limitation occurred before the seed filling and the plant mechanisms and processes underlying seed yield and protein concentrations were leaf area index, absorbed solar radiation, and N remobilization. Finally, there was a trade-off between biological N2 fixation and indigenous soil N supply with fixation reduced less than proportional per unit increase in indigenous N sources. There was a temporal asynchrony between biological N2 fixation and N demand, that is, biological N2 fixation was not sufficient to meet plant N demand as the latter increased and the contribution of indigenous soil N supply decreased. The peak of indigenous soil N supply was the most important factor explaining variation in the N limitation across environments. Findings from this study will help to narrow soybean yield gap to meet future food demand. Advisor: Patricio Grassin

Understanding Nitrogen Limitation in Soybean

Meeting soybean demand on existing cropland area for a global population of 9.7 billion people by the year 2050 requires narrowing the existing gap between average producer yield and yield potential. Soybean relies on two sources on nitrogen (N): biological N2 fixation and indigenous soil N 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 sources and fixation becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. This study evaluated N limitation across 29 high-yield soybean environments in Argentina and Nebraska from 2015 to 2017. Each environment 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 novel protocol developed also in this study. Seed yield and protein concentration in full N were 11% and 3% higher than zero-N, respectively. The magnitude of the difference depended upon the yield level of the production environment, ranging from 0 kg ha-1 at 2.5 Mg ha-1 up to 900 kg ha-1 at 6 Mg ha-1. Seed yield responses were directly related with increases in accumulated N in aboveground biomass (70 kg N ha-1), without changes in nitrogen use efficiency. The N limitation was mitigated in environments with large contribution of indigenous soil N supply. The maximum rates of N limitation occurred before the seed filling and the plant mechanisms and processes underlying seed yield and protein concentrations were leaf area index, absorbed solar radiation, and N remobilization. Finally, there was a trade-off between biological N2 fixation and indigenous soil N supply with fixation reduced less than proportional per unit increase in indigenous N sources. There was a temporal asynchrony between biological N2 fixation and N demand, that is, biological N2 fixation was not sufficient to meet plant N demand as the latter increased and the contribution of indigenous soil N supply decreased. The peak of indigenous soil N supply was the most important factor explaining variation in the N limitation across environments. Findings from this study will help to narrow soybean yield gap to meet future food demand

Understanding Nitrogen Limitation In Soybean

Meeting soybean demand on existing cropland area for a global population of 9.7 billion people by the year 2050 requires narrowing the existing gap between average producer yield and yield potential. Soybean relies on two sources on nitrogen (N): biological N2 fixation and indigenous soil N 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 sources and fixation becomes insufficient to meet crop N requirements for high yields, while still maintaining or increasing protein and oil concentration. This study evaluated N limitation across 29 high-yield soybean environments in Argentina and Nebraska from 2015 to 2017. Each environment 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 novel protocol developed also in this study. Seed yield and protein concentration in full N were 11% and 3% higher than zero-N, respectively. The magnitude of the difference depended upon the yield level of the production environment, ranging from 0 kg ha-1 at 2.5 Mg ha-1 up to 900 kg ha-1 at 6 Mg ha-1. Seed yield responses were directly related with increases in accumulated N in aboveground biomass (70 kg N ha-1), without changes in nitrogen use efficiency. The N limitation was mitigated in environments with large contribution of indigenous soil N supply. The maximum rates of N limitation occurred before the seed filling and the plant mechanisms and processes underlying seed yield and protein concentrations were leaf area index, absorbed solar radiation, and N remobilization. Finally, there was a trade-off between biological N2 fixation and indigenous soil N supply with fixation reduced less than proportional per unit increase in indigenous N sources. There was a temporal asynchrony between biological N2 fixation and N demand, that is, biological N2 fixation was not sufficient to meet plant N demand as the latter increased and the contribution of indigenous soil N supply decreased. The peak of indigenous soil N supply was the most important factor explaining variation in the N limitation across environments. Findings from this study will help to narrow soybean yield gap to meet future food demand. Advisor: Patricio Grassin