Nitrogen Fertilization and Cropping System Impacts on Soil Quality in Midwestern Mollisols

Abstract

High grain production of corn (Zea mays L.) can be maintained by adding inorganic N fertilizer, and also by using crop rotations that include alfalfa (Medicago sativa L.), but the relative impact of these management practices on soil quality is uncertain. We examined the effects on soil of N fertilization rate (0, 90, 180, 270 kg ha −1 , corn phase only) in four cropping systems: CC, continuous corn; CS, corn-soybean [Glycine max (L.) Merr.]; CCOA, corn-corn-oat (Avena sativa L.)-alfalfa; and corn-oat-alfalfa-alfalfa (COAA). The 23-and 48-yr-old experimental sites, situated in northeast (Nashua) and north central (Kanawha) Iowa, were in a replicated split-plot design and managed with conventional tillage. At Nashua, we measured available N, potential net N mineralization and microbial biomass C (MBC) throughout the growing season; all were significantly higher in the CCOA system. At both sites, post-harvest N stocks, and soil organic C (SOC) concentrations were significantly higher in systems containing alfalfa. Grain yield was most strongly correlated with soil N properties. At Nashua, N fertilizer additions resulted in significantly lower soil pH (0-to 15-cm depth) and lower exchangeable Ca, Mg, and K and cation exchange capacity (CEC) in the CC and CCOA systems. In an undisturbed prairie reference site for Nashua, low available N, low pH, and high CEC suggested a strong influence of the vegetation on nutrient cycling. In terms of management of soil fertility, inclusion of alfalfa in the rotation differed fundamentally from addition of N fertilizer because high yield was maintained with fewer adverse effects on soil quality. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. ABSTRACTHigh grain production of corn (Zea mays L.) can be maintained by adding inorganic N fertilizer, and also by using crop rotations that include alfalfa (Medicago sativa L.), but the relative impact of these management practices on soil quality is uncertain. We examined the effects on soil of N fertilization rate (0, 90, 180, 270 kg ha 21 , corn phase only) in four cropping systems: CC, continuous corn; CS, corn-soybean [Glycine max (L.) Merr.]; CCOA, corn-corn-oat (Avena sativa L.)-alfalfa; and corn-oat-alfalfa-alfalfa (COAA). The 23-and 48-yr-old experimental sites, situated in northeast (Nashua) and north central (Kanawha) Iowa, were in a replicated split-plot design and managed with conventional tillage. At Nashua, we measured available N, potential net N mineralization and microbial biomass C (MBC) throughout the growing season; all were significantly higher in the CCOA system. At both sites, post-harvest N stocks, and soil organic C (SOC) concentrations were significantly higher in systems containing alfalfa. Grain yield was most strongly correlated with soil N properties. At Nashua, N fertilizer additions resulted in significantly lower soil pH (0-to 15-cm depth) and lower exchangeable Ca, Mg, an...

The Influence of No-Till, Conventional Tillage and Nitrogen Fertilization on Physico-Chemical and Biological Indicators After Three Years of Monoculture Barley

“…On the contrary, the effect of nitrogen fertilization is significant, although the differences are too small (1 cmol + kg -1 for the upper 5 cm layer and 0.6 for the 20 cm layer) to assume agronomic importance. No-till generally determines an increase in CEC parallel to the organic matter, whereas large amounts of nitrogen fertilizer have a tendency to reduce it (Russell et al, 2006). In this trial, the small CEC increases in the N 2 subplots could be attributed to the organic matter increases in the upper 10 cm of the soil profile.…”

Assessment of Soil Quality of Croplands in the Corn Belt of Northeast China

“…Russell [34] studied the fertilization addition under different N fertilization rates (0, 90, 180 and 270 kg/ha), and found that for continuous corn cropping systems, N fertilizer additions resulted in remarkably lower soil pH (0 to 15 cm depth), lower exchangeable Ca, Mg and K, and CEC [34]. In our study, the result of the ANOVA showed that the difference between the two groups was insignificant.…”

“…Different fertilization treatments have different effects on soil properties in different crop systems, increasing or decreasing the contents of some soil nutrients [34]. Russell [34] studied the fertilization addition under different N fertilization rates (0, 90, 180 and 270 kg/ha), and found that for continuous corn cropping systems, N fertilizer additions resulted in remarkably lower soil pH (0 to 15 cm depth), lower exchangeable Ca, Mg and K, and CEC [34].…”

Managing excess water in Canadian prairie soils: A review

“…It is also a high-water use plant, and with its deep roots, serves to draw down the water table to a much greater depth than annual crops, reducing the risk of secondary salinity associated with a shallow water table (Ridley et al 2001). As a nitrogen-fixing plant, it may also provide a fertility benefit to subsequent annual crops (Russell et al 2006). Alfalfa is the most widely researched forage crop for both water and salinity management, but other crops may be more appropriate under excess water conditions.…”