Biomass Production of an Overwinter Cover Crop with Biofumigation Properties in New Mexico

Abstract

Soil-borne diseases and weeds can be inhibited by mustard family (Brassicaceae) cover crops that are mowed and incorporated into the soil with tillage—a process referred to as biofumigation. To determine whether a fall-seeded mustard cover crop produces enough biomass to be a biofumigant in spring, this study measured the amount of biomass produced by a mixture of ‘Caliente Rojo’ brown mustard (Brassica juncea) and ‘Nemat’ arugula (Eruca sativa) grown in three commercial fields and a university research farm in southern New Mexico, USA. This study also determined whether the mustard biomass incorporated in the soil inhibits a weed [Palmer amaranth (Amaranthus palmeri)], but does not affect a cash crop adversely [chile pepper (Capsicum annuum)]. Results indicated that, if the mustard cover crop was seeded before the first frost in fall, mustard cover crops produced biomass in quantities sufficient for biofumigation in spring. Mustard biomass incorporated in the soil reduced the survival and germination of Palmer amaranth seeds. Under greenhouse conditions, chile pepper plants grown in soil with mustard cover crop biomass were larger than chile plants grown in soil without mustard biomass. Chile pepper plants in soil with mustard biomass did not show symptoms of Verticillium wilt (Verticillium dahliae), whereas such symptoms were found on about 33% of chile pepper plants in soil without mustard biomass. These results suggest that a fall-seeded mustard cover crop that is tilled into the soil in early spring is a potential pest management technique for chile pepper in New Mexico.

The effects of microplastics on crop variation depend on polymer types and their interactions with soil nutrient availability and weed competition

“…2008; Nagila et al . 2022). A. retroflexus is classified as an invasive weed based in the Alien Invasive Flora of China (Ma 2020) and the online Flora of China (http://www.efloras.org).…”

“…Amaranthus retroflexus L. is a common annual agricultural weed in the Amaranthaceae, native to North America and common in 80 countries worldwide (Qin et al 2018). In addition, A. retroflexus L. often competes with the E. sativa in agricultural fields (Moeini et al 2008;Nagila et al 2022). A. retroflexus is classified as an invasive weed based in the Alien Invasive Flora of China (Ma 2020) and the online Flora of China (www.efloras.org).…”

Timing Termination of a Biofumigant Cover Crop for Weed Suppression in Chile Pepper

“…To determine the amounts of sinigrin added to soil by cover crops ended on different dates, measurements of cover crop biomass at termination were combined with date-specific measurements of sinigrin concentrations in cover crop biomass. Measurements of cover crop biomass at termination generally followed the procedures of Nagila et al (2022). Specifically, just before cover crop termination, aboveground biomass of mustard cover crops was clipped at the soil surface and collected from four 0.25-m 2 quadrats (0.5 m width × 0.5 m length) within each plot.…”

“…A previous study suggested that early-season weeds in New Mexico chile pepper were suppressed by biofumigation with a brown mustard cover crop that was seeded in fall and ended 20 to 24 d before chile pepper seeding in spring (Nagila et al 2022). This biofumigation treatment also promoted chile pepper growth under greenhouse conditions by reducing the incidence of Verticillium wilt caused by Verticillium dahliae (Nagila et al 2022). Before using or recommending biofumigation with an overwinter brown mustard cover crop, it is prudent to know how this cover crop interacts with an insect that transmits a viral disease to chile pepper.…”