Does an increase in available nitrogen improve the seed yield and protein of field-grown soybean under irrigation and drought conditions?

ERGO, VERÓNICA V.; SALVAGIOTTI, FERNANDO; CARRERA, CONSTANZA S

Hong Kong

Congreso; International Symposium on Agricultural Genomics for Food Security and Plant-Environment Interaction in a Changing Climate; 2023

The Chinese University of Hong Kong

Does an increase in available nitrogen improve the seed yield and protein of field-grown soybean under irrigation and drought conditions? (Theme: Underutilized crops and nutritional research)Ergo Verónica1,2, Salvagiotti Fernando2.3, Carrera S. Constanza1,2,41 Unidad de Estudios Agropecuarios (UDEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Instituto Nacional de Tecnología Agropecuaria (INTA), Córdoba, Argentina.2 CONICET, Argentina.3 Estación Experimental Agropecuaria INTA Oliveros, Santa Fe, Argentina.4 Department of Agricultural and Forest Sciences and Engineering, University of Lleida - AGROTECNIO (Center for Research in Agrotechnology), Lleida, Spain.Increasing food production and its quality is a challenge in the context of global population growth and climate change. Thus, research on plant-environment interactions is of high priority for improving field crops performance under stressful scenarios. Our goal was to evaluate the increase in nitrogen (N) availability in non-transgenic soybean genotypes, contrasting in seed protein concentration, under irrigated and drought conditions during the seed filling period on seed yield, number, weight, protein, and oil concentrations and contents. We conducted two field experiments during two crop seasons testing two genotypes: high (HP) and low (LP) seed protein. Treatments included two water levels: irrigated (640 millimeters summing up irrigation and rain) and drought (being the soil water content ≤ 25% of field capacity from R5 phenological stage), and two N levels: unfertilized (N0) and fertilized (N+; 600 kg N ha-1 equally split at vegetative, beginning bloom, and beginning pod stages). Regardless of genotype and N levels, the drought significantly reduced seed yield by 71% and oil concentration by 9%. In irrigated plots, independently of genotypes, N+ decreased seed weight, protein, and oil contents by 11% compared to N0, with no significant changes in seed protein and oil concentrations. Under drought, N+ increased seed weight by 12% and seed oil content by 9% in both genotypes. Interestingly, under drought and N+ combination, the HP genotype increased the seed protein content, increasing seed protein concentration by 5%. The harvest index in the HP genotype was 30% higher in this condition, evidencing a higher biomass partition capacity to seed compared to N0. Based on these results it emerges that an increase in the N availability under drought conditions might improve the seed yield components and protein concentration and content, mainly in the genotype with higher N demand (i.e., HP genotype).