Cover cropping has a potential to improve soil health in semiarid regions. This research evaluated the effects of spring-planted cover crops on selected soil health indicators in limited-irrigated winter wheat (Triticum aestivum L.)-fallow system. Soil health parameters measured include soil water content (SWC), soil organic carbon (SOC), soil total nitrogen (STN), potentially mineralizable carbon (PMC), potentially mineralizable nitrogen (PMN), permanganate oxidizable carbon (POXC), inorganic N, and available P. Cover crops tested were pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea + oat (PO), pea + canola (PC), pea + oat + canola (POC), pea + oat + canola + hairy vetch (Vicia villosa L.) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.) (SSM), and a fallow. Cover crops were planted in February and terminated in May after 85 to 90 d. Cover crop biomass was 33 to 142% greater with oat, PO, PC, POC, and SSM than pea and canola. The SWC was 2 to 3% lower under cover crops than fallow plots at their termination, but was 2 and 4% greater in SSM and POC than fallow at wheat planting in October. Soil inorganic N was 41 to 49% lower with cover crops than fallow at termination date. Soil PMC and POXC varied with cover crop species and sampling dates. The SOC and STN contents were 18 to 20% greater with oat than PC. Oat and its mixture with other cover crops show promises to improve soil health and resilience.

Decline in soil organic carbon (SOC) and the associated impacts on crop production under conventional farming raises concerns on how alternative management practices increase SOC sequestration and improve agricultural sustainability. This study aimed to understand SOC mineralization kinetics with different cover crop (CC) residue amendments. Soil samples were collected from a fallow and three CC (pea, oat, and canola) plots. Soil samples from the CC plots were manipulated with zero, five, and 10 Mg ha −1 of the respective CC residues. All soil samples were incubated for eight weeks, SOC mineralization was monitored, and the first order kinetic and parabolic equation models were fitted to the observed data for estimating labile SOC (C 0 ), and the decomposition rate constant (k). Subsequent comparisons of fitted model parameters were based on the first order kinetic model. The C 0 varied with the residue amount while k varied with CC type. C 0 was 591-858% greater with 10 Mg ha −1 and 289-456% greater with five Mg ha −1 residue additions while k was 122-297% greater with 10 Mg ha −1 and 94-240% greater with five Mg ha −1 residue additions when compared to the fallow treatment. The CC residue stimulated cumulative carbon mineralization (C min ) irrespective of CC type, suggesting that cover cropping has potential to improve SOC cycling in agroecosystems.

Reducing the fallow period by using cover crops in a winter wheat (Triticum aestivum L.)–sorghum [Sorghum bicolor (L.) Moench]–fallow system has the potential to suppress weeds and improve wheat yield, yet limited information is available from the semiarid southern Great Plains (SGP) of the United States. This study determines the effects of spring‐planted cover crops on weed suppression and winter wheat yields in semiarid environments. The study used a randomized complete block design with eight cover crop treatments and three replications. The cover crop treatments consisted of fallow (weeds controlled with herbicide), pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea + oat, pea + canola, pea + oat + canola, and six‐species mixture of pea + oat + canola + hairy vetch (Vicia villosa L.) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.). Both winter wheat and cover crops received supplemental irrigation. The cover crops showed potential to suppress weeds and maintain good ground cover during summer. Specifically, weed biomass in the oat and oat mixtures with legumes and brassicas were 73 to 85% less than in fallow during 2018. Cover crops showed little effect on wheat yield, yield components, and water use efficiency. Although long‐term studies of cover crops effects on multiple ecosystem services may help to select the most effective cover crop on wheat yield and water use efficiency in the SGP, this study revealed benefit of cover cropping through weed suppression.

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