Department of Agronomy, Horticulture and Plant Science, South Dakota State University, Brookings, South Dakota, USA.
Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, Tennessee, USA.
Sci Rep. 2020 Apr 30;10(1):7334. doi: 10.1038/s41598-020-64182-2.
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 (PCG-0N), 75 kg N ha (PCG-75N), 150 kg N ha (PCG-150N), and 225 kg N ha (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 CH and CO fluxes were similar for all the treatments over the study period. However, the PCG-KC, PCG-0N, and PCG-75N recorded lower cumulative NO fluxes (384, 402, and 499 g N ha, respectively) than the PCG-150N (644 g N ha) and PCG-255N (697 g N ha). 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 CO-eq ha) compared to the PCG-225N (227.78 kg CO-eq ha), but similar to other treatments. Soil total N was 15%% and 13% higher under PCG-KC (3.7 g kg) than that under PCG-0N (3.2 g kg) and PCG-75N (3.3 g kg), respectively. This study concludes that intercropping prairie cordgrass with kura clover can enhance biomass yield and reduce fertilizer-derived NO emissions and net global warming potential.
高羊茅（PCG）（ Spartina pectinata Link）对土壤盐分和渍水有很强的耐受性，因此，它可以在边缘土地上生长。优化氮（N）投入对于实现 PCG 理想的生物量生产至关重要，而不会对环境产生负面影响。因此，本研究基于以下假设：将金雀花三叶草（ Trifolium ambiguum M. Bieb.）（KC）等豆科植物作为与 PCG 的间作，可以为作物提供额外的 N，减少额外的 N 肥料，并减轻土壤表面温室气体（GHG）排放。研究的具体目标是评估不同 N 施用量管理的 PCG [0 kg N ha（PCG-0N）、75 kg N ha（PCG-75N）、150 kg N ha（PCG-150N）和 225 kg N ha（PCG-255N）]和与 KC 间作的 PCG 对 GHG 通量和生物量产量的影响。该实验于 2010 年在南达科他州的一个低产农田中建立。使用静态室在 2014 年至 2018 年的生长季节测量 GHG 通量。计算了净全球变暖潜势（GWP）。数据显示，在整个研究期间，所有处理的累积 CH 和 CO 通量相似。然而，PCG-KC、PCG-0N 和 PCG-75N 记录的累积 NO 通量（分别为 384、402 和 499 g N ha）低于 PCG-150N（644 g N ha）和 PCG-255N（697 g N ha）。PCG-KC 在 2016 年和 2017 年的产量分别比 PCG-0N 高出 85%和 39%，与其他处理（PCG-75N、PCG-150N 和 PCG-255N）的产量相似。与 PCG-225N（227.78 kg CO-eq ha）相比，PCG-KC 的净 GWP 低 52%（112.38 kg CO-eq ha），但与其他处理相似。PCG-KC 下的土壤总氮（N）比 PCG-0N（3.2 g kg）和 PCG-75N（3.3 g kg）分别高 15%和 13%（3.7 g kg）。本研究得出结论，与金雀花三叶草间作高羊茅可以提高生物量产量，减少肥料衍生的 NO 排放和净全球变暖潜势。
