Irrigation, carbon amelioration, nitrogen, and stover removal effects on continuous corn

Abstract

Corn (Zea mays L.) residue or stover is harvested as supplemental feed for livestock and is a potential feedstock for cellulosic biofuels. Limited information is available on corn stover removal effects on grain yield under different irrigation rates, nitrogen (N) fertilizer rates, and practices to maintain soil carbon (C) and minimize soil erosion. We evaluated potential interactions between irrigation rate (full or limited), C amelioration practices (cover crop, surface‐applied manure, or no amelioration practice), fertilizer N management (125 or 200 kg N ha−1), and stover removal (residue removal or no residue removal), on no‐till continuous corn grain yield located on a silt loam soil in south‐central Nebraska (2011–2018). Stover removal increased (P = .0017) grain yield by 1.02 Mg ha−1 and grain N uptake compared with no stover removal. Manure increased corn grain yield by 899 kg ha−1 compared to either the control or cover crop with stover removal while C amelioration practices did not affect grain yield under stover retention. Grain N concentration was higher (P < .0001) with stover removal (13.2 g kg−1) than residue retained (12.7 g kg−1). Partial factor productivity (grain yield/N rate) was highest for manure treatments with residue removal. The farmgate N balance (N applied − N removed) from stover removal was negative, yet grain yield was not affected after eight growing seasons. Grain yield increased with stover removal and manure application resulting in a cost‐effective C amelioration practice whereas incorporating a winter cover crop resulted in similar grain yield as the control.

Comparing impacts of corn residue removal and amelioration practices on soil properties after 3, 6, and 10 years

“…However, irrigation treatment did not cause a significant irrigation rate × residue removal effect, which suggests that at this location, residue removal effects on soil properties were similar across the two irrigation rates. This may be due to the irrigation rate having limited effects on crop yields (12.7 Mg ha −1 in full irrigation vs. 12.3 Mg ha −1 in deficit irrigation) and residue yields in this study (8.7 Mg ha −1 in full irrigation vs. 8.4 Mg ha −1 in deficit irrigation) (Schmer et al., 2020).…”

“…Although residue removal had negative effects on various soil properties, grain yield was significantly higher under residue removal (12.6 Mg ha −1 ) than no removal (12.1 Mg ha −1 ) over the duration of this study, averaged across amelioration and irrigation treatments with 200 kg N ha −1 fertilization rate (Schmer et al., 2020). This may be due to the effects of residue removal on most soil properties only occurring near the soil surface (top 10 cm).…”

“…Also, this study occurred in an irrigated cropping system where reduced water retention in residue removal plots may have been offset by irrigation water additions. Interestingly, manure application provided little benefit to soil properties but significantly increased grain yields (Schmer et al., 2020). Grain yield was 12.6 Mg ha −1 with manure application, 12.2 Mg ha −1 with no amelioration practice, and 12.3 Mg ha −1 with cover cropping at 200 kg N ha −1 averaged across removal and irrigation treatments.…”

“…The levels were 100% of the irrigation requirement (full) and 60% of the irrigation requirement (deficit). Average annual irrigation was 95 ± 9 mm for the deficit irrigation treatment and 158 ± 16 mm for the full irrigation treatment (Schmer et al., 2020). Plots were first split into 24‐m by 52‐m subplots and treated with three amelioration practices: none, winter rye cover crop, or cattle manure application.…”

“…Further description of the layout of this study is in Schmer et al. (2020) and Blanco‐Canqui et al. (2014).…”