04602naa a2200289 a 450000100080000000500110000800800410001902200140006002400270007410000200010124501050012126000090022650012090023552025630144465000140400765300120402165300200403365300230405365300220407670000160409870000170411470000170413170000180414870000160416670000150418277301150419710633182022-12-02       2022    bl uuuu     u00u1 u    #d  a0003-47467 a10.1111/aab.127452DOI1 aJÁUREGUI, J.M.  aYield gaps of lucerne (Medicago sativa L.) in livestock systems of Argentina.h[electronic resource]  c2022  aArticle history: Received: 24 March 2021/ Revised: 8 October 2021/ Accepted: 9 October 2021. -- Corresponding author: Jáuregui, J.M.; Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, Kreder 2807, Santa Fe, Esperanza, Argentina; email:josemartinjauregui@gmail.com -- Funding:  The authors thank Dr Gonzalo Berhongaray for his insightful comments that helped to improve the manuscript and an anonymous referee who provided valuable feedback. The authors also wish to specially thank everyone involved in the data collection of the NLCEN (Valeria Arolfo, Ariel Odorizzi, Daniel Basigalup, Silvia Olivo, Luis Romero, Alejo Re, Cecilia Sardiña, Laura Fontana, Néstor Romero, Mario Funes, Mónica Cornacchione, Elena Di Nucci, Juan José Gallego, Fernanda Neira Zilli, Dante Pueyo and Lourdes Mijoevich). FAL was financially supported by PROCISUR and FONTAGRO through the project “Uso de leguminosas en sistemas ganaderos sudamericanos”. GDB was financially supported by INTA (project “Incremento sostenible de la producción y utilización de pasturas y forrajes conservados”) and FCA-UNMDP (project “Uso responsable del nitrógeno en ganadería: fertilización y leguminosas”).  aAbstract: Argentina grows the second-largest area of lucerne in the world. Despite its importance, a yield gap exists between potential and measured yields, but factors contributing to it are still unclear. This study aimed to identify management factors and research needs to reduce the lucerne yield gap to improve the livestock systems in this region. We used meteorological data coupled with lucerne crop modelling and measured yields from the National Lucerne Cultivar Evaluation Network (NLCEN) to quantify the lucerne yield gap in nine sites located within the Argentinian Pampas (between parallels 30?45°S and meridians 58?65°W) and three sites outside the Pampas. Specifically, we used the model developed by McCall & Bishop-Hurley (2003), adapted and calibrated for lucerne in Argentina by Berone et al. (2017) to estimate the potential yield (PY) for 12 locations (three irrigated and nine rainfed), and compared those results with measured yields from the NLCEN to calculate yield gaps. We found the average available photosynthetic active radiation (PAR) and temperatures were sufficient to achieve 21.5 ±?3.7 t dry matter (DM) ha?1 yr?1 under rainfed conditions (environments with mean annual rainfall from 400 to 1,200?mm). However, the average measured yield from the NLCEN was 16.8 ±?2.4 t DM ha?1 yr?1 (a 22% gap). Potential yields ranged between 10 and 25?t DM ha?1 yr?1 under rainfed conditions and between 25 and 39?t DM ha?1 yr?1 for irrigated crops. As latitude increased rainfed locations had lower yields, while irrigated locations had higher yields. Adding irrigation was predicted to increase yields to 35.4 ±?2.0 t DM ha?1 yr?1 (a 53% gap) in rainfed sites. For irrigated locations, the gap was smaller (27.3 ±?3.5 vs 32.4 ±?2.2 t DM ha?1 yr?1 for measured vs potential yield, respectively), and most likely linked to nutrient deficits. Also, current grazing management was estimated to achieve approximately 50% less grazing efficiency than optimal grazing management. Our results demonstrated that the livestock industry can potentially increase animal production under current environmental conditions. The four main adjustments to achieve this are increased use of irrigation, increased use of fertilisers, earlier commencement of grazing in spring and increased stocking rates. The costs of irrigation, fertilisers and grazing management are envisaged to be small compared with potential increases in incomes and thus profitability available to beef and dairy farmers using lucerne as a major feed source in Argentina.  aARGENTINA  aALFALFA  aCROP MANAGEMENT  aGRAZING MANAGEMENT  aMEDICAGO SATIVA L1 aOJEDA, J.J.1 aBERONE, G.D.1 aLATTANZI, F.1 aBAUDRACCO, J.1 aFARIÑA, S.1 aMOOT, D.J.  tAnnals of Applied Biology, July 2022, Volume 181, Issue 1, pages 22-32. doi: https://doi.org/10.1111/aab.12745