Short‐term corn yield response associated with nitrogen dynamics from fall‐seeded cover crops under no‐till dryland conditions

Abstract

The availability of in‐season N to corn (Zea mays L.) following fall‐seeded cover crops depends on seasonal patterns of nitrogen (N) transformations that are site‐ and year‐dependent and resist prediction. Our objectives were to evaluate N dynamics following different cover crops (legume, nonlegume, none) and their relationship with subsequent corn yields within an established no‐till winter wheat (Triticum aestivum L.)–cover crop/corn–soybean (Glycine max) rotation over two site‐years in the U.S. Northern Plains. Spring cover crop biomass and N uptake, in‐situ soil N mineralization following cover crop termination, and corn grain yield and N uptake were measured. Legume cover crops were associated with higher corn yields, whereas rye (Secale cereale) did not significantly decrease corn yields despite N immobilization by a large rye cover crop in one year. Legume cover crops produced the highest rates of N mineralization during periods of high N demand by corn (V6–R3) and the highest seasonal amounts of mineralized N compared with rye or no cover crops. In‐situ N mineralization measurements better predicted yields across all treatments compared with approaches using cover crop biomass and N content. In situ N mineralization rates during corn growth stages V6–R3 provided a superior prediction (r = .83) of corn yields compared with all seasonal estimates of N provided by cover crops. Lower apparent N use efficiency calculated with contributions of in‐season N mineralization indicated that less fertilizer N can be applied in the growing season following legume cover crops.

Cover crop application on dredged sediments increases corn yield through microorganism-associated enzyme-driven nutrient mineralization.

“…2010) the use of winter rye cover crop provided bene cial relationships different than those previously described following winter rye use. Speci cally, we found that corn yields increased with increased N mineralization following cover crop application, which contrasts previous research using winter rye (Chim et al 2022). The increases in kernel count driven by N-mineralization-associated enzyme activities supports our hypothesis for coupling a cover crop with dredged sediments for agricultural use, which is the goal of using soil amendments in agricultural systems.…”

“…Additionally, cover crop application was not bene cial for photosynthetic e ciency as e ciency was signi cantly greater in the control plot left fallow during vegetative development and decreased over time regardless of treatment. Responses for corn grown in dredged sediments following cover crop application varied from those documented within non-dredged sediment amended agricultural systems, with many bene ts missing(Mahama et al 2016; Acharya et al 2020;Chim et al 2022). Although corn yield was the only plant response to bene t from cover crop application due to changes in soil properties, the combination of cover crop application with dredged sediments may be bene cial but not necessary to improve corn production.Soil Properties Differ in Response to Cover Crop ApplicationSeveral dredged sediment soil properties failed to signi cantly vary between the cover crop and non-cover crop plots.…”