Intercropping kura clover with prairie cordgrass mitigates soil greenhouse gas fluxes

Abstract

Prairie cordgrass (PCG) (Spartina pectinata Link) has a high tolerance to soil salinity and waterlogging, therefore, it can thrive on marginal lands. Optimizing the nitrogen (N) input is crucial to achieving desirable biomass production of PCG without negatively impacting the environment. Thus, this study was based on the hypothesis that the use of legumes such as kura clover (Trifolium ambiguum M. Bieb.) (KC) as an intercrop with PCG can provide extra N to the crop reducing the additional N fertilizer and mitigating soil surface greenhouse gas (GHG) emissions. Specific objective of the study was to assess the impact of PCG managed with different N rates [0 kg N ha−1 (PCG-0N), 75 kg N ha−1 (PCG-75N), 150 kg N ha−1 (PCG-150N), and 225 kg N ha−1 (PCG-255N)], and PCG intercropped with KC (PCG-KC) on GHG fluxes and biomass yield. The experimental site was established in 2010 in South Dakota under a marginally yielding cropland. The GHG fluxes were measured from 2014 through 2018 growing seasons using the static chamber. Net global warming potential (GWP) was calculated. Data showed that cumulative CH4 and CO2 fluxes were similar for all the treatments over the study period. However, the PCG-KC, PCG-0N, and PCG-75N recorded lower cumulative N2O fluxes (384, 402, and 499 g N ha−1, respectively) than the PCG-150N (644 g N ha−1) and PCG-255N (697 g N ha−1). The PCG-KC produced 85% and 39% higher yield than the PCG-0N in 2016 and 2017, respectively, and similar yield to the other treatments (PCG-75N, PCG-150N, and PCG-255N) in these years. Net GWP was 52% lower for the PCG-KC (112.38 kg CO2-eq ha−1) compared to the PCG-225N (227.78 kg CO2-eq ha−1), but similar to other treatments. Soil total N was 15%% and 13% higher under PCG-KC (3.7 g kg−1) than that under PCG-0N (3.2 g kg−1) and PCG-75N (3.3 g kg−1), respectively. This study concludes that intercropping prairie cordgrass with kura clover can enhance biomass yield and reduce fertilizer-derived N2O emissions and net global warming potential.

Growing Jatropha (Jatropha curcas L.) as a Potential Second-Generation Biodiesel Feedstock

“…The composition of triglycerides with C16-C18 corresponds to the hydrocarbon structure of diesel. Thus, Jatropha oil could be used directly as diesel as a road transportation fuel without further processing [128]. Generally, standard biodiesel and J. curcas oil compare well to petroleum-based diesel [5].…”

Soil greenhouse gas emissions, organic carbon and crop yield following pinewood biochar and biochar–manure applications at eroded and depositional landscape positions: A field trial in South Dakota, USA

“…Biochar and manure have been documented to be effective in reducing CH 4 flux from waterlogged soils, the largest source of global CH 4 flux (Feng et al, 2012;Khan et al, 2013;Kim et al, 2014). Dry cropping systems have been found to emit inconsiderable amounts of CH 4 in previous research (Abagandura et al, 2020;Bhattarai et al, 2021;Singh et al, 2020).…”

Intercropping prairie cordgrass with kura clover had little effect on soil biogeochemistry

“…Several studies have reported the benefits of PCG-KC intercropping (Abagandura et al, 2020;Kim et al, 2020;Sekaran et al, 2020). For example, a previous study in South Dakota by Sekaran et al (2020) reported that PCG-KC intercropping enhances soil microbial communities when compared to the PCG monocultures fertilized with different levels of N in a silty clay loam soil type.…”

“…However, this experiment was conducted only after crop harvest, and there is a lack of understanding of changes in the biological properties during the crop growth period. In another study conducted on a silty clay loam soil type, Abagandura et al (2020) reported that after 7 years of intercropping, PCG-KC enhances soil organic carbon (SOC), total nitrogen (TN), and different soil C and N fractions such as cold and hot water extractable C and N and microbial biomass C and N in the topsoil (0-to 15-cm soil depth)…”