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The fate of 15N labeled urea in a soybean-wheat cropping sequence under elevated CO2 and/or temperature
- Lenka, Narendra Kumar, Lenka, Sangeeta, Mahapatra, Prabhakar, Sharma, Niharika, Kumar, Sanjeev, Aher, Satish B, Yashona, Dharmendra Singh
- Agriculture, ecosystems & environment 2019 v.282 pp. 23-29
- carbon dioxide, carbon dioxide enrichment, climate change, climatic factors, cropping sequence, crops, fertilizers, grain yield, harvesting, metabolism, nitrogen, seed yield, seeds, soil, soybeans, stable isotopes, temperature, total nitrogen, urea
- Changing climate has direct linkage with growth and metabolism in plants and is likely to alter nitrogen (N) uptake from fertilizers. Hence, a field study was conducted using 15N labeled urea in micro-plots to study the effects of elevated CO2 and/or temperature on fertilizer-N use in a soybean-wheat cropping sequence. Crops were grown in open top field chambers (OTCs) under two CO2 (386 and 558–561 ppmv), two temperature (ambient, 1.4-1.5 °C above) and three N levels during 2017-18. The N treatments were 50, 100 and 150% of the recommended dose (N50, N100 and N150). Labeled (15N) urea (10% atom excess) was applied to soybean. Elevated CO2 and/or temperature showed significant effects on seed yield, total N uptake, fertilizer-N uptake, per cent N derived from fertilizer (Ndff) and per cent fertilizer-N use in the soybean-wheat crop sequence. Total N uptake in soybean significantly increased under elevated CO2 and/or temperature treatments, mainly due to higher N uptake in seeds. Effect of climate on fertilizer-N uptake and utilization in the soybean-wheat cropping sequence varied with level of N application. The 15N labeled fertilizer-N uptake and per cent fertilizer-N use was significantly higher under co-elevation of both CO2 and temperature at N100 and N150, but, was mostly similar among the climate treatments at N50. In the soybean-wheat crop sequence, 13–40% of the applied fertilizer was used, with significantly higher use with co-elevation of both CO2 and temperature. Out of the applied fertilizer, 20–51% got retained in the surface soil and 43–73% was traced in the soil-plant system. Significantly higher fertilizer-N use in the soybean-wheat crop sequence under co-elevation of CO2 and temperature indicates increasing role of fertilizer-N to harvest the CO2 mediated enhancement in grain yield under the future climate conditions.