No-till seeded spinach after winterkilled cover crops in an organic production system

Abstract

Organic no-till (NT) management strategies generally employ high-residue cover crops that act as weed-suppressing mulch. In temperate, humid regions such as the mid-Atlantic USA, high-residue winter cover crops can hinder early spring field work and immobilize nutrients for cash crops. This makes the integration of cover crops into rotations difficult for farmers, who traditionally rely on tillage to prepare seedbeds for early spring vegetables. Our objectives were to address two separate but related goals of reducing tillage and integrating winter cover crops into early spring vegetable rotations by investigating the feasibility of NT seeding spinach (Spinacia oleracea L.), an early spring vegetable, into winterkilled cover crops. We conducted a four site-year field study in the Piedmont and Coastal Plain regions of Maryland, USA, comparing seedbed conditions and spinach performance after forage radish (FR) (Raphanus sativus L.), a low-residue, winterkilled cover crop, spring oat (Avena sativa L.), the traditional winterkilled cover crop in the area, a mixture of radish and oat, and a no cover crop (NC) treatment. NT seeded spinach after FR had higher yields than all other cover crop and tillage treatments in one site year and was equal to the highest yielding treatments in two site years. Yield for NT spinach after FR was as high as 19 Mg ha−1 fresh weight, whereas the highest yield for spinach seeded into a rototilled seedbed after NC was 10 Mg ha−1. NT seeding spring spinach after a winterkilled radish cover crop is feasible and provides an alternative to both high-residue cover crops and spring tillage.

The Current State and Future Directions of Organic No-Till Farming with Cover Crops in Canada, with Case Study Support

“…High rates of weed suppression by crimped cover crops are documented in organic vegetable production, including spaghetti squash (Cucurbita pepo), pumpkin (Cucurbita pepo), bulb onion (Allium cepa), and spinach (Spinacia oleracea) [34,36,37]. In growing spinach, forage radish (Raphanus sativus var.…”

“…In growing spinach, forage radish (Raphanus sativus var. longipinnatus) mixed with oats (Avena sativa) and monoculture forage radish and oats as cover crops in OrgNT reduce weed infestation to the levels of rototilled bare fields of spinach [37]. In the case of bulb onions, foxtail millet (Setaria italica) mulch suppresses more weeds with more biomass than cowpea (Vigna unguiculata) mulch, but the latter results in higher yields [36].…”

“…This method was designed collaboratively at Rodale Institute to achieve a number of goals, unavailable through other termination methods like those employing mowers [9] (pp. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. The roller-crimper lays down a cover crop neatly and evenly and crushes the mature stems without severing them [9] (p. 44).…”

“…The emergence is reduced and blooming delayed for snap beans under a crimped rye cover crop, despite the lower weed biomass with rye than under vetch [35]. Spinach shows a greater success in a low-mulch-covered field after winterkilled forage radish, at just under two times the yield of rototilled methods [37]. Research suggests that favorable climate conditions override the biomass maximization when growing marketable OrgNT vegetables.…”

Organic no-till and strip-till systems for broccoli and pepper production

“…Some researchers reported yields similar to or exceeding those of CT Lounsbury and Weil, 2014;Vollmer et al, 2010), but others observed yield reduction when using NT (Delate et al, 2003;. Risk due to this inconsistency-combined with the need for specialized equipment and different management strategies-has slowed grower adoption of these systems.…”