Improved soil biological health increases corn grain yield in N fertilized systems across the Corn Belt

Abstract

Nitrogenous fertilizers have nearly doubled global grain yields, but have also increased losses of reactive N to the environment. Current public investments to improve soil health seek to balance productivity and environmental considerations. However, data integrating soil biological health and crop N response to date is insufficient to reliably drive conservation policy and inform management. Here we used multilevel structural equation modeling and N fertilizer rate trials to show that biologically healthier soils produce greater corn yields per unit of fertilizer. We found the effect of soil biological health on corn yield was 18% the magnitude of N fertilization, Moreover, we found this effect was consistent for edaphic and climatic conditions representative of 52% of the rainfed acreage in the Corn Belt (as determined using technological extrapolation domains). While N fertilization also plays a role in building or maintaining soil biological health, soil biological health metrics offer limited a priori information on a site's responsiveness to N fertilizer applications. Thus, increases in soil biological health can increase corn yields for a given unit of N fertilizer, but cannot completely replace mineral N fertilization in these systems. Our results illustrate the potential for gains in productivity through investment in soil biological health, independent of increases in mineral N fertilizer use. Since the Green Revolution, nitrogenous mineral fertilizers have helped to nearly double global grain crop yields 1. While this represents monumental gains in crop productivity, an estimated 41 to 50% of the N fertilizer applied to corn (Zea mays L.) globally since of the Green Revolution has been lost to the environment 2 , resulting in multifarious negative environmental effects 3-5. Many strategies to address N losses from cropping systems are centered on the management of N fertilizer (e.g., "4Rs" of fertilizer management 6), but neglect the role of soil 4,5 biology in supplying plant N which often supplies over 50% plant N uptake in a growing season 7-9. The framework of soil health seeks to highlight the critically important 10 , albeit inherently complex and uncertain 11,12 , role of soil biology in agroecosystems. Ultimately, soil health seeks to integrate soil biology with the historically emphasized chemical and physical soil components 13,14. Soil health has been widely embraced by farmers, researchers, and private industry alike 15-18. Additionally, soil health has also accrued broad legislative support in the form of nearly a dozen states incentivizing improved soil health as well as a Soil Health division within USDA 19. Buy-in from these stakeholders represents a nexus of several key sources of information growers use in making nutrient management decisions 20-22 , as well as a demonstrated financial commitment. While soil health has broad conceptual support, there is a dearth of empirical evidence connecting soil biological health measurements to vital soil functions or desired outcomes 23. Althou...

Deficit saline water irrigation under reduced tillage and residue mulch improves soil health in sorghum-wheat cropping system in semi-arid region

“…Application of organic residues and mulching normally increases the N mineralization potential of soils, responsible for, an increase in KMnO 4 -N 32 , 33 . Increased DHA, Ur and α / β- glu activities in mulching also pointed to the greater soil metabolic activity responsible for organic N mineralization 34 . Although mulching improved the KMnO 4 -N, it was decreased by mulching in deficit irrigation treatments.…”

Effect of Nitrogen Levels and Application Scheduling on the Growth and Yield of Maize

“…Chisanga et al, (2020) reported that there were significant differences in grain yields under different levels of NPK and application, i.e., the arrangement of fractional applications had a significant impact on crop index. Similarly, Wade et al, (2020) also reported a significant effect of nitrogen fertilizer allocation on corn grain yield. Similarly, Fernandez, (2020) reported the effects of pre-planting and nitrogen application on maize yield and found that nitrogen application before planting was significantly higher (7.6-10.6%) than before corn planting.…”

Soil health conceptualization differs across key stakeholder groups in the Midwest

“…Conceptually, farmers see a linkage between soil health and agrochemical inputs and crop productivity. However, only a handful of studies have explored these linkages using common soil health tests (Franzluebbers 2018;Yost et al 2018;Wade et al 2020), despite farmers demonstrating a greater willingness to implement information derived from a soil test than from nontest sources (Tao et al 2012). Therefore, although the overall usage of soil health tests was low amongst farmers, the information farmers glean from those tests is both valuable and more likely to be implemented.…”