Green bridge crops to manage corn nitrogen nutrition in the Southeastern Argentinean Pampas

An ecological intensification of agriculture through the use of green bridge crops (GBC) between cash crops is a way to improve resource use efficiency. This study aimed to assess vetch (Vicia villosa Roth.) (Ve), oat (Avena sativa L.) (Oa), Oa+Ve as GBC, and a control without GBC, with different termination dates (early and late), tillage systems (conventional tillage and no-tillage), and nitrogen (N)-fertilization to corn (Zea mays L.) (NF: 0 and 120 kg N ha−1) on soil N availability, and corn N uptake and yield. Three field experiments were carried out at the Southeastern Argentinean Pampas in 2012–2013, 2013–2014, and 2014–2015 on an Argiudoll. Corn and GBC aboveground dry matter and N accumulation and corn grain yield were determined. Soil nitrate-N at corn planting and V6 and anaerobically mineralizable N (AN) at corn planting were also determined. Water availability at corn planting was not limiting, whereas along corn cycle differed among years. The GBC terminated late accumulated more dry matter and N than those terminated early and Ve and Oa+Ve more N than Oa. Both early termination date and Ve tended to show higher nitrate-N at planting and at V6 stage. In general, NF improved corn behavior but response was different among GBC, being lower after Ve and Oa+Ve, and with late termination date. A simple model was fitted to predict corn relative yield based on nitrate-N at V6 stage, AN, GBC dry matter accumulation and C:N ratio. The model fitted allowed predicting relative corn grain yield and could be used as a tool to help N fertilization recommendation.EEA BalcarceFil: Crespo, Cecilia. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Crespo, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Corral, Raúl Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Chacra Experimental Integrada Barrow; Argentina.Fil: Diez, Santiago. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Delgado, Santiago. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Domínguez, Germán. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Agostini, María de los Ángeles. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Cendoya, María Gabriela. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Sainz Rozas, Hernán Rene. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Sainz Rozas, Hernán Rene. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Sainz Rozas, Hernán Rene. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: García, Gisela. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Studdert, Guillermo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina