Long‐term rotation diversity and nitrogen effects on soil organic carbon and nitrogen stocks

Abstract

Understanding the impacts of long‐term fertilizer management and rotation diversity on soil C and N is needed under a changing climate. The objective of this study was to evaluate the effects of N fertilizer level and crop rotation diversity on soil organic carbon (SOC) and soil N stocks from a 34‐yr study located in eastern Nebraska. Seven crop rotations (three continuous cropping systems; two 2‐yr crop rotations; and two 4‐yr crop rotations) and three N levels were compared. Soil samples were taken to a depth of 150 cm. Differences in SOC stocks were largely confined to the 0‐ to 7.5‐cm depth, with greater SOC (P = .0002) in rotations than continuous cropping systems and greater SOC (P = .0004) in 4‐yr vs. 2‐yr rotations. Total soil N was greater with increased crop rotation diversity for the 0‐ to 30‐cm soil profile. Greater SOC levels occurred with N fertilization for the 0‐ to 7.5‐cm depth. At the 0‐ to 150‐cm soil depth, SOC stocks were similar between N levels and greater for the 4‐yr vs. 2‐yr crop rotations (P = .0492). Trends in total N stocks were similar to those of SOC stocks. Overall, crop rotation had a larger effect on SOC and N stocks than N fertilizer.

Crop rotational diversity can mitigate climate‐induced grain yield losses

“…The benefits of CRD for crop performance under low and high precipitation are likely mostly mediated by changes to soil properties and ecosystem functioning. Increasing CRD could improve soil structure and soil organic matter content, facilitating the retention of water and nutrients in several field experiments (Kremen & Miles, 2012; Schmer et al., 2020; Sprunger et al., 2020). Nevertheless, trade‐offs might occur if the added crops increase water demands, as observed in some experiments (Blanchy et al., 2023), in the absence of sufficient soil water recharge outside the growing season.…”

Effects of tillage and cropping sequences on crop production and environmental benefits in the North China Plain

“…Results from present study also show that soybean-based crop rotation may reduce the SOC sequestration capacity of CA when compared to maize in NCP. However, most of the previous studies reported that: decomposition of crop residues could be accelerated by soybean compared to maize, and thus increase SOC content (Huggins et al, 2007;Schmer et al, 2020). The differences may be induced by the reduction of C input (King and Blesh, 2018) and the short experimental duration (Shrestha et al, 2013).…”

Compost and biosolids increase long-term soil organic carbon stocks

“…Furthermore, the increase in the soil organic carbon in the agroecosystem with crop rotation system was due to the type of crops used in our study. Schmer et al (2020) found that significant soil organic carbon accretion in a 2-year and 4-year crop rotation compared to continuous cropping after 34 years can be attributed to the rotation complexity. The authors further noted that crops used in the rotation affects the residue mass and quality (i.e., carbon-nitrogen ratio) returned to the soil, which later contributes to the nitrogen immobilization.…”

“…Although the application rate of nitrogen fertilizer was lower compared to biobased residues, nutrient availability was highest for the fertilizer and lowest for the compost. This is because the compost had the highest carbon to nitrogen ratio, and lowest microbial carbon-use efficiency resulting in high soil organic carbon accumulation compared to nitrogen fertilizer (Schmer et al 2020;Badewa et al 2022). Manzoni et al (2012) observed that substrates with high carbon to nitrogen ratios, due to their nitrogen limitation, have a low microbial carbon-use efficiency.…”