Spring‐planted cover crop effects on weed suppression, crop yield, and net returns in no‐tillage dryland crop production

Abstract

Integrating cover crops (CCs) into dryland crop rotations could provide options for herbicide-resistant (HR) weed control in no-tillage (NT) systems. Field experiments investigated weed suppression potential of spring-planted CCs and their effects on plant available water, crop yields, and net returns. The CC treatments were implemented during the fallow phase of NT wheat (Triticum aestivum L)-sorghum (Sorghum bicolor Moench)-fallow rotation at two locations: Brownell and Colby, over 3 yr in western Kansas. Treatments were oat-triticale (OT), oat-triticale-pea (Pisum sativum; OTP), spring pea, and fallow. Spring pea aboveground biomass was 3,290 kg ha −1 , whereas OT produced 5,640 kg ha −1 and OTP produced 5,260 kg ha −1 . Regardless of location, weed biomass was reduced between 86 and 99% with CCs relative to weedy fallow. Cover crops reduced plant available water at winter wheat planting in three out of the six site-years. Averaged across years, CCs reduced winter wheat yields by 18% compared with fallow at Brownell but not at Colby.Replacing fallow with spring pea increased gross revenue but generated negative net returns because of high cost of herbicide and pea seed. Net return with OT or OTP CCs were negative in four out of six site-years when used strictly for weed suppression. However, net returns were mostly positive when OT ($110-876) or OTP (−$110-832) CCs were used as forage. Our results showed replacing fallow with spring-planted CCs for weed suppression in dryland cropping system is profitable only when the CCs are used for forage.

Grazing cover crops: How does it influence soils and crops?

“…The cost of grazing a CC is also affected by infrastructure, or lack thereof, in place or that must be provided (i.e., perimeter fencing and water), and seed cost based on species grown (Tobin et al., 2020). Several CC studies have shown that seed cost is a factor in determining profitability, with low seed cost systems often being profitable and high seed cost systems being unprofitable (Holman et al., 2018, 2022; Obour, Dille, et al., 2022; Obour, Holman, et al., 2022). Furthermore, low seed cost species also tend to produce more biomass (grass vs. legume), and those species with greater forage yield imply greater animal unit days.…”

“…Additional research is needed on the amount of CC residue that can be removed through grazing while still maintaining the benefits of growing a CC. The more CC residue removed by grazing, the greater the near‐term economic return from the production system (Holman et al., 2018, 2022; Obour, Dille, et al., 2022; Obour, Holman, et al., 2022). However, removing too much CC residue might negate the positive long‐term soil health benefits of growing a CC (Simon et al., 2021, 2022).…”

Efficacy and economics of light‐activated sensor‐controlled sprayer for site‐specific weed control

“…Due to the high cost of controlling multiple HR weeds with alternative herbicides, some producers are reverting to tillage as a cost‐saving weed management strategy. This shift poses a major threat to gains and investments made in soil conservation practices over the last several decades (Obour et al., 2022). In addition, infrequent annual rainfall and declining water levels of the Ogallala Aquifer will further lead to an expansion of the dryland acreage in the U.S. Great Plains (Deines et al., 2020).…”

Short-Term Agronomic and Economic Responses to the Adoption of Cover Crops for Corn Rotation in the Brazilian Semiarid Region

“…Increasing plant diversity is a fundamental strategy to optimize crop efficiency [1], promote yield stability, and mitigate the negative impacts of monoculture practices [2]. The adoption of cover crops (CCs), with their distinct characteristics and multiple benefits [2,3], has emerged as a promising approach to enhancing corn yields in semiarid regions [4,5].…”

“…In these areas, limited water availability, due to irregular rainfall patterns and high temperatures, can hinder the effectiveness of this practice [19,20]. Water competition and nutrient immobilization between CCs and cash crops [5] may lead to reduced corn yields [20], jeopardizing the economic viability of cultivation [4,21]. Corn plays a critical role in the food chain in this region, making sustainable and adapted agricultural practices essential to ensure both food and economic security.…”