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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #383291

Research Project: Ecologically-Sound Pest, Water and Soil Management Practices for Northern Great Plains Cropping Systems

Location: Agricultural Systems Research

Title: Soil profile carbon, nitrogen, and crop yields affected by cover crops in semiarid regions

item ACHARYA, PRAMOD - New Mexico State University
item GHIMIRE, RAJAN - New Mexico State University
item CHO, YOUNGKOO - Eastern New Mexico University
item THAPA, VESH - New Mexico State University
item Sainju, Upendra

Submitted to: Nutrient Cycling in Agroecosystems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2022
Publication Date: 2/4/2022
Publication URL:
Citation: Acharya, P., Ghimire, R., Cho, Y., Thapa, V., Sainju, U.M. 2022. Soil profile carbon, nitrogen, and crop yields affected by cover crops in semiarid regions. Nutrient Cycling in Agroecosystems. 122:191-203.

Interpretive Summary: Cover crops can provide many ecosystems services, but cover crop benefits under limited irrigated systems in the semiarid region are not clear. Researchers from ARS, Sidney, MT in collaboration with New Mexico State University conducted a five-year study on the effect of cover crop on soil carbon and nitrogen and winter wheat and sorghum yields in the winter wheat-sorghum-fallow rotation. They found that cover crop did not affect soil organic carbon, but soil total and inorganic nitrogen were 6-156% greater with the fallow than cover crops. Cover crops also did not affect water-filled pore space. Oat and the fallow treatment increased sorghum grain yield by 33-97% compared to other cover crops, but winter wheat yield was not affected by cover crop. Although cover crops increased sorghum yield, authors concluded that more than five years of study is needed to observe the effect of cover crop on soil carbon and nitrogen storage under limited irrigation system in the semiarid region of the southern Great Plains.

Technical Abstract: Cover crops are increasingly adopted for improving soil health in arid and semiarid regions. However, their effect on soil profile organic carbon (C) and nitrogen (N) and crop yield are not consistent. The objective of this study (2016–2020) was to evaluate cover crop effect on soil C and N contents and water-filled pore space to a depth of 80 cm and crop yield in a winter wheat (Triticum aestivum L.) – sorghum (Sorghum bicolor L. Moench) – fallow (WSF) rotation. Cover crop treatments were fallow (no cover crop), pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea-canola mixture (PCM), pea-oat mixture (POM), pea-oat-canola mixture (POCM), and six species mixture of POCM, hairy vetch (Vicia villosa Roth), forage radish (Raphanus sativus L.), and barley (Hordeum vulgare L.) (SSM). Five years of cover cropping did not affect soil organic C (SOC). Soil total N (STN) was 6–14% greater in fallow than other treatments, except POM. The fallow treatment also had 54–156% and 11–72% higher inorganic N content than cover crop treatments at ESM layers of 2500–5000 and 5000–7500 Mg ha-1. Water-filled pore space (WFPS) did not vary among treatments. Sorghum grain yield was 33–97% higher following fallow and oat than following other cover crops in 2019 and 2020. Although oat cover crop enhanced sorghum yield in some years, cover crops largely unaffected soil profile C and N contents under limited irrigated cropping systems in the semiarid region.