Effects of Living Mulch and Fertilizer on the Performance of Broccoli in Plasticulture

Abstract

Living mulch systems allow cover crops to be grown during periods of cash crop production, thereby extending the duration of cover crop growth and associated beneficial agroecosystem services. However, living mulches may also result in agroecosystem disservices such as reduced cash crop yields if the living mulch competes with the crop for limiting resources. We examined whether the effects of an Italian ryegrass [Lolium multiflorum (Lam.) Husnot]-white clover (Trifolium repens L., cv. New Zealand) living mulch on broccoli (Brassica oleracea L. var. italica) yield and yield components were dependent on fertilizer rate in field experiments conducted in Durham, NH, in 2011 (Expt. 1) and 2012 (Expt. 2). Drip-irrigated broccoli was grown under a range of organic fertilizer application rates in beds covered with plastic, with and without a living mulch growing in the uncovered, interbed space. Broccoli yields were similar in the living mulch and bare soil controls under the highest rates of fertilizer application in Expt. 1. In Expt. 2, living mulch reduced broccoli yields from 28% to 63%, depending on fertilizer rate. Differences in leaf SPAD values suggest that yield reductions were attributable, in part, to competition for nitrogen; however, other factors likely played a role in determining living mulch effects. Despite yield reductions, the living mulch reduced the prevalence of hollow stem in broccoli in Expt. 1. Organic fertilizer may have inconsistent effects on broccoli yields in living mulch systems.

Mulching as a physical weed control method applicable in medicinal plants cultivations

“…Apart from weeds suppression, advantages of the use of living mulches also include efficient control of erosion, reduction of nitrate leaching, better soil structure and improved pest and disease self-regulation. The living mulch concept has been tested with a number of typical row crops, such as maize [15], sunflower [16], soybeans [17], cabbage [18], broccoli [19] and strawberry [20], but the emphasis has been given to leguminous plants, especially the white clover (Trifolium repens).…”

Cover Crop Performance between Plastic-mulched Beds: Impacts on Weeds and Soil Resources

“…Although this separation has the potential to reduce risks of competition relative to a nonplasticulture living mulch system, previous studies have demonstrated that cash crop yield reductions often do occur when living mulches are grown between plastic-mulched beds (Butler, 2012;Law et al, 2006;Nelson and Gleason, 2018;Reid, 2015;Reid and Klotzbach, 2013;Reiners and Wickerhauer, 1995;Warren et al, 2015).…”

“…Previous living mulch studies outside of plasticulture systems have investigated strategies to mediate competition between a living mulch and cash crop, including species selection, use of supplemental nutrients and irrigation, delayed planting or early termination of the living mulch, spatial separation between the living mulch and the cash crop, and complementary weed management practices such as cultivation or herbicides Pfeiffer et al, 2016;Walters and Young, 2008). Within the context of a plasticulture system, Warren et al (2015) found higher rates of an organic fertilizer eliminated yield reductions due to an Italian ryegrass/clover living mulch in plasticulturegrown broccoli in 1 of 2 years. Broccoli leaf chlorophyll (SPAD) measurements supported the hypothesis that competition for soil N was a factor in yield reductions, and the authors speculated that conditions encouraging living mulch root incursion under plastic-covered raised beds (e.g., low precipitation) may have contributed to differences in the severity of competition between the 2 years.…”

Mustard Cover Crop Growth and Weed Suppression in Organic, Strawberry Furrows in California

“…Many previous studies on cover crops and plastic mulch with vegetable systems have focused on cover crops as replacements for the plastic mulch (Abdul-Baki et al, 2002;Chellemi and Rosskopf, 2004;Duzy et al, 2014;Lilley and Sanchez, 2016;Maul et al, 2014;Tillman et al, 2015). In contrast, relatively little research has been carried out on ways to improve the sustainability of plastic-mulched systems by interplanting cover crops in furrows in other regions of the United States (Rice et al, 2001(Rice et al, , 2007Warren et al, 2015). The work by Rice et al focused on rye (Secale cereale L.) to reduce erosion and pesticide loads in runoff in conventional tomato (Solanum lycopersicum L.) systems, whereas Warren et al used a grass-legume living mulch to extend cover crop duration in organic broccoli (Brassica oleracea L. var.…”

“…Furrow cover crops could potentially impact the yield of strawberries through below-or aboveground competition. A study with cover crops between plastic-mulched broccoli beds found lower marketable yields in broccoli with cover crops in the furrows (Warren et al, 2015), but in that case, the living mulch cover crop grew alongside the broccoli up to broccoli harvest and was repeatedly mowed. However, preliminary data indicate that strawberry yields are unaffected by well-managed mustard cover crops in furrows (Brennan, unpublished data, 2014).…”