Location: Agricultural Systems ResearchTitle: Improving dryland cropping system nitrogen balance with no-tillage and nitrogen fertilization
|GHIMIRE, RAJAN - New Mexico State University|
|PRADHAN, GAUTAM - North Dakota State University|
Submitted to: Journal of Plant Nutrition and Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2019
Publication Date: 3/12/2019
Citation: Sainju, U.M., Ghimire, R., Pradhan, G.P. 2019. Improving dryland cropping system nitrogen balance with no-tillage and nitrogen fertilization. Journal of Plant Nutrition and Soil Science. 182:374-384. https://doi.org/10.1002/jpln.201800630.
Interpretive Summary: Nitrogen fertilizer is applied in large amounts to sustain crop yields, but excessive application beyondwhat the crop needs can degrade soil and environmental quality by increasing soil acidification, nitrogen leaching, and greenhouse gas emissions. Little is known about management effects on nitrogen flows in soil, crop, and the environment and nitrogen balance which measures dryland agroecosystem performance and environmental sustainability. ARS researchers in Sidney, MT found that a no-till barley-pea rotation with a reduced nitrogen fertilization rate can enhance dryland crop nitrogen removal and reduce nitrogen loss to the environment compared with conventional till crop-fallow with the recommended nitrogen rate. A no-till legume-nonlegume crop rotation with a reduced amount of nitrogen fertilizer can enhance agroecosystem performance and environmental sustainability while reducing external nitrogen inputs in dryland cropping systems.
Technical Abstract: Studies on N balance due to N inputs and outputs and soil N retention to measure agroecosystem performance and environmental sustainability are limited due to the complexity of measurements of some parameters. We measured N balance based on N inputs and outputs and soil N retention under dryland agroecosystem affected by tillage and cropping sequence combination and N fertilization from 2006 to 2011 in the northern Great Plains. Tillage and cropping sequences were conventional tillage barley (Hordeum vulgaris L.)-fallow (CTB-F), no-tillage barley-fallow (NTB-F), no-tillage barley-pea (Pisum sativum L.) (NTB-P), and no-tillage continuous barley (NTCB). Nitrogen rates to barley were 0, 40, 80, and 120 kg N ha-1. Total N input due to N fertilization, pea N fixation, soil N mineralization, atmospheric N deposition, crop seed N, and nonsymbiotic N fixation and total N output due to grain N removal, denitrification, volatilization, plant senescence, N leaching, gaseous N (NOx) emissions, and surface runoff were 28 to 37% greater with NTB-P and NTCB than CTB-F and NTB-F and increased with increased N rate. Nitrogen sequestration rate at 0 to 10 cm averaged 22 kg N ha-1 yr-1 for all treatments. Nitrogen deficit ranged from 5 to 16 kg N ha-1 yr-1, with greater deficits for CTB-F and NTB-P and lower N rates. Because of increased grain N removal and reduced N loss to the environment and N fertilizer requirement, NTB-P with 40 kg N ha-1 can enhance agronomic performance and environmental sustainability while reducing external N inputs compared with other management practices.