Climate Change and Management Impacts on Soybean N Fixation, Soil N Mineralization, N2O Emissions, and Seed Yield

Abstract

Limited knowledge about how nitrogen (N) dynamics are affected by climate change, weather variability, and crop management is a major barrier to improving the productivity and environmental performance of soybean-based cropping systems. To fill this knowledge gap, we created a systems understanding of agroecosystem N dynamics and quantified the impact of controllable (management) and uncontrollable (weather, climate) factors on N fluxes and soybean yields. We performed a simulation experiment across 10 soybean production environments in the United States using the Agricultural Production Systems sIMulator (APSIM) model and future climate projections from five global circulation models. Climate change (2020–2080) increased N mineralization (24%) and N2O emissions (19%) but decreased N fixation (32%), seed N (20%), and yields (19%). Soil and crop management practices altered N fluxes at a similar magnitude as climate change but in many different directions, revealing opportunities to improve soybean systems’ performance. Among many practices explored, we identified two solutions with great potential: improved residue management (short-term) and water management (long-term). Inter-annual weather variability and management practices affected soybean yield less than N fluxes, which creates opportunities to manage N fluxes without compromising yields, especially in regions with adequate to excess soil moisture. This work provides actionable results (tradeoffs, synergies, directions) to inform decision-making for adapting crop management in a changing climate to improve soybean production systems.

Leguminous plants significantly increase soil nitrogen cycling across global climates and ecosystem types

“…Generally, symbiotic N fixation by legumes is highly sensitive to water availability (Dovrat & Sheffer, 2019). A number of tropical and temperate legumes exhibit a reduction in N fixation when subjected to soil moisture deficiencies (Elli et al, 2022; Markham & Anderson, 2021; Rousk et al, 2017), mainly because nitrogenase activities rely on the quantity of carbohydrates supplied to nodules, and the supply decreases under water‐limited conditions (Arfin‐Khan et al, 2014). In addition, the limitations in legume growth induced by drought result in lower nodule biomass and N fixation rates (McCulloch et al, 2021).…”

Ranking genotype, environment, management effects on the optimum nitrogen rate for maize: A cropping system modeling analysis

“…Soil‐specific parameters included changes to the watertable depth, the residual fall N pools, and soil organic carbon ±15%, similar to Elli et al. (2022).…”

“…The irrigation amount was limited to a minimum of 5-day intervals to better represent reality. Soil-specific parameters included changes to the watertable depth, the residual fall N pools, and soil organic carbon ±15%, similar to Elli et al (2022).…”

“…We used the baseline 30year weather data per location and increased the daily average temperatures by 1.3˚C, decreased the summer rain by 6%, and increased spring rain by 3% using APSIM's climate controller script to reflect the 2050 decade. The relative changes in weather were held constant across locations and derived from Elli et al (2022), who analyzed 15 future climate scenarios reflecting three representative concentration pathways (RCP 2.6, RCP 7.0, and RCP 8.5) and five climate models. We did not consider elevated CO 2 as maize (i.e., a C4 plant) displays a limited response to increasing CO 2 on photosynthetic activity greater than current atmospheric concentrations (Twine et al, 2013;Wang et al, 2020).…”

Agriculture evolution, sustainability and trends, focusing on Brazilian agribusiness: a review

“…Rainfed agriculture is the prevalent method in agricultural countries around the world, with irrigation systems being used in a few cases, generally in small areas and crops with a higher financial return per cultivated area (He and Rosa, 2023). Therefore, most agriculture worldwide is prone to adversities imposed by climate changes, such as lack or excess of rain, hailstorms, cross-stress due to this imbalance (e.g., nutritional, pathogens, insect pests, others), weakening of the soil and microbiota, changes in planting, pruning, and harvesting windows, and incompatibility of some commercial cultivars to the production regions with seasonally changed climatic conditions (Howden et al, 2007;Elli et al, 2022). On the one hand, the regional climatic balance and uniformity have enabled the development and consolidation of commercial cultivars with highly adapted agronomic characteristics for each of these regions, but with these severe and non-linear climate changes, cultivars and the plant breeding pipeline need to be often optimized (Tillman et al, 2011;Rezaei et al, 2023).…”