Large Single-head Broccoli Yield as Affected by Plant Density, Nitrogen, and Cultivar in a Plasticulture System

Abstract

<jats:p>An open-market window has been identified in Virginia for fall broccoli (<jats:italic>Brassica oleracea</jats:italic> var. <jats:italic>italica</jats:italic>). Vegetable producers using plasticulture systems can capitalize on this opportunity by growing broccoli as a second crop after summer vegetables. The objective of this project was to evaluate suitability of two broccoli cultivars, Everest and Gypsy, for the fall production of large single-heads (&gt;6 inches in diameter) for the fresh market. Planting density and rate of nitrogen (N) fertilizer (25, 60, and 100 lb/acre N) effects on yield characteristics were evaluated in a plasticulture system during a 3-year study (2003–05) conducted with broccoli transplants at the Virginia Polytechnic Institute and State University Kentland Agricultural Research Farm near Blacksburg, VA. The percentage of large heads was cultivar, plant density, and N rate dependent. The midseason ‘Gypsy’ produced significantly higher total yield and head weight compared with the early-season ‘Everest’. The optimum density to maximize floret production per area was 12,500 plants/acre and a supplemental N rate of 100 lb/acre. This N rate significantly (<jats:italic>P</jats:italic> &lt; 0.002) improved marketable yield, large head yield, and leaf N accumulation compared with the lower rates. The data indicate that the feasibility of growing fall broccoli using a plasticulture system depends on the number of large heads produced for the fresh market. This in turn will depend on the choice of cultivar, stand establishment, and the requirement for supplemental N fertilizer over the residual level available in the soil after the first crop.</jats:p>

Effect of nitrogen doses and inter crops on growth and yield of broccoli (Brassica oleracea L. var. italica)

“…The highest total yield was recorded in N 3 (145.47 q/ha) followed by N 2 (143.11 q/ha), and lowest yield was obtained in N 1 (134.19 q/ha). Similar results were also reported by Bashyal et al, (2013); El-Helaly, ((2012); Schellenberg et al, (2009); Yoldas et al, (2008);Monirruzaman et al, (2007) at their place in broccoli. The intercropping systems showed nonsignificant variation for total yield of broccoli.…”

Increasing Plant Density in Eastern United States Broccoli Production Systems to Maximize Marketable Head Yields

“…Eastern vegetable growers have typically used lower plant densities than those tested in this study. This may be largely due to the recommendations made by eastern researchers (i.e., Dufault and Waters 1985;Schellenberg et al, 2009). Several earlier studies evaluating plant density effects on broccoli production were done several decades ago when higher populations were being tested for western production systems (Cutcliffe, 1971(Cutcliffe, , 1975Palevitch, 1970).…”

“…Jett et al (1995) found no significant effect of plant density on days to harvest in a 1990 trial, but observed that days to harvest was up to 9 d later with a density of 108,000 plants/ha compared with that of 36,000 plants/ha in a 1991 trial. In another Virginia study, Schellenberg et al (2009) examined plant densities ranging from 18,000 to 48,000 plants/ha and within-row spacing of 9 to 24 inches, respectively, using the more modern hybrid 'Gypsy' as well as the older 'Everest' in a plasticulture system. This study found that 'Gypsy' was the preferred cultivar using a plant density of 35,000 plants/ha, yielding 11,500 kgÁha -1 .…”

Competitive Biomass Allocation Between the Main Shoot and Lateral Branches of Broccoli (<i>Brassica oleracea</i> L. var. <i>italica</i>)

“…The seedlings were transplanted on 15 Feb. 2017 into the study field, covered with black plastic mulch and placed in transparent low plastic tunnels (PVC film, 0.075 mm thickness) at a planting density of 1.6 plants•m −2 (160 cm between ridges and 40 cm between plants). The practical density for heading type broccoli is 3.0-3.6 plants•m −2 (Jett et al, 1995;Schellenberg et al, 2009), but we set approximately half of this density to accommodate the development of branches. The field was fertilized with N, P 2 O 5 , and K 2 O at rates of 4, 4, and 3 kg•a −1 , respectively.…”