Soil nutrient managmement: Fueling agroecosystem sustainability

Authors: Young, Eric

Submitted to: Electronic Publication
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/2/2020
Publication Date: 7/23/2020
Citation: Young, E.O. 2020. Soil nutrient managmement: Fueling agroecosystem sustainability. Electronic Publication. https://doi.org/10.1080/14735903.2020.1792679.
DOI: https://doi.org/10.1080/14735903.2020.1792679

Interpretive Summary: Production and efficiency of agricultural systems must increase to meet global food demand while mitigating nutrient losses to air and water. Managing the amount, form, timing, and placement of crop nutrients to optimize crop yield/quality while minimizing losses to the environment (nutrient management) is a critical component of sustainability. Crop yield has traditionally been the main focus of agriculture, however high input costs, low/variable commodity prices, erratic weather, societal externalities (water and air quality) and stringent regulations necessitate both economic and environmental efficiency measures. Nutrient use efficiency (NUE) estimates the quantity of applied nutrient taken up by a crop during the season and is affected by soil type, weather, crop species, tillage and other management factors and varies widely. Most fertility guidelines are based on the probability of optimum economic yield, which accounts for the reduction in yield with continued nutrient application beyond optimal. While progress has been made toward improving NUE, much work remains. Dynamic N mass balance and other farm system nutrient management modeling tools aimed at incorporating weather, soil biogeochemical processes, and management factors show promise for enhancing NUE but need further testing. Precision-based and real-time modeling tools can enhance NUE while targeting nutrient mitigation practices where necessary.

Technical Abstract: Agricultural production must approximately double to support global population by the year 2050. Determining best practices for enhancing nutrient use efficiency (NUE) while promoting soil health and water quality will become increasingly relevant for farms of all sizes. Developing a nutrient management plan using realistic crop yield goals and regional fertility guidelines are important first steps to developing a nutrient management plan. Due to the complexity of nutrient cycling and factors affecting crop growth/nutrient loss (soil spatial variability, climate/weather, soils, and topography), real-time geospatial tools and variable rate fertilizer application can increase NUE compared to uniform rate applications. Crops such as corn and sugarcane require large amounts of fertilizer N and more advanced modeling tools in addition to more routine testing (i.e., soil/tissue testing, static N budgeting) are needed to optimize NUE and reduce losses to runoff water and the atmosphere. Real-time, dynamic N simulation models may improve N management by accounting for losses driven by early season weather compared to static approaches, but additional field testing and validation are needed. Whole-farm system models in dairy and livestock operations aim to simulate major biophysical farm components (including weather-driven soil-water and field nutrient dynamics) to better quantify nutrient loss pathways and determine practices to increase NUE. Real-time geospatial/precision-based modeling tools offer the potential to increase NUE while targeting mitigation practices where necessary and should be encouraged at a range of farm scales.