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Togo Shinohara, Shinsuke Agehara, Kil Sun Yoo, and Daniel I. Leskovar

Globe artichoke [Cynara cardunculus L. var. scolymus (L.) Fiori] has been recently introduced as a specialty crop in southwest Texas. Marketable yield, yield components, quality, and phenolic compounds of artichoke heads were investigated in response to three irrigation [50%, 75%, and 100% crop evapotranspiration (ETc)] regimes and four nitrogen (0 to 10, 60, 120, and 180 kg·ha−1) rates under subsurface drip irrigation. Field experiments were conducted over three seasons (2005–2006, 2006–2007, and 2007–2008) at Uvalde, TX. Irrigation was more effective than nitrogen (N) rates to optimize crop yield and head quality. Marketable yields significantly increased at 100% ETc compared with 75% and 50% ETc, whereas a 20% to 35% yield reduction occurred at 50% ETc across seasons. This yield reduction was associated with a decrease in both number of marketable heads and head weight and with reductions in plant physiological responses as measured in the last season. The lack of yield responses to N rates was in part the result of high pre-plant soil NO3-N and NH4-N levels. Total phenolics and chlorogenic acid of artichoke heads increased as the harvesting season progressed and were highest at 50% ETc during mid- and late harvests in one season. Based on these results, we estimate that under these environmental conditions, ≈700 mm (for a bare soil system) of water inputs and 120 kg·ha−1 or less of N (rate depending on soil available N) appear sufficient to obtain high marketable yields, superior size, and nutritional head quality of artichokes.

Free access

Daniel Leskovar, Smiljana Goreta, Kil Sun Yoo, Giovanni Piccinni, and Shinsuke Agehara

Introduction of artichokes in the Wintergarden of Texas, an area with mild winters and hot summers, depends on the development of strategies that will overcome limiting climatic conditions for bolting, earliness, and length of harvest. Cultivars with different bolting requirements were evaluated at two planting times and irrigation rates. The cultivars Emerald, Experimental Red, Imperial Star, Green Globe, and Purple Romagnia were transplanted in the field on 27 Sept. and 3 Dec. 2004, and evaluated at 100% and 75% crop evapotranspiration rates (ETc) at Uvalde, Texas (29°1' N; 99°5' W). Harvests started on 24 Mar. and 21 Apr. 2005 for the first and second planting dates, respectively. Yield increased more than 3-fold for the first compared to the second planting date. Irrigation rates did not affect yield, water use efficiency, or head quality. The cultivars Emerald, Imperial Star, and Experimental Red were earlier than Green Globe and Purple Romagnia. The highest yield was measured for cv. Imperial Star, while the largest head weight was for cv. Green Globe. Total fibers, crude protein, and phenolic compounds concentration depended on cultivar, whereas the total sugar concentrations in the edible part of the head were similar among cultivars. Head weight, percentage of heart, and crude protein concentration decreased, whereas total fiber content increased as the harvesting season progressed. Integrating environmental and cultivar strategies aimed at earliness, large head size, and enhanced level of health-promoting compounds, will contribute to the potential production of globe artichokes in the region.

Open access

Ravneet K. Sandhu, Nathan S. Boyd, Shaun Sharpe, Zhengfei Guan, Qi Qiu, Tianyuan Luo, and Shinsuke Agehara

Strawberry growers face rising production costs combined with competition from foreign imports. Relay cropping vegetables with strawberries is a unique approach that can diversify income and reduce the risk associated with strawberry production. Planting vegetable transplants on the same bed before strawberry crop termination enables continued berry harvesting while the new vegetable transplants become established. Relay cropping techniques of strawberry with eggplants were evaluated during the 2016–17 and 2017–18 seasons in Balm, FL. The strawberry crop was planted in September, and eggplant was transplanted into the beds either as a sole crop or with strawberry plants. Two experiments were conducted to optimize the planting date of strawberries and the termination date of strawberries. The objective of the research was to examine the competitive relationship between strawberry and eggplant crops and to define the optimal planting date for the eggplant and termination date of strawberries to minimize the competitive interaction and maximize the yield of both crops. Strawberry yields were unaffected (P = 0.938) by relay cropping or by the planting date of the eggplant. Eggplants grown without strawberries had 27% to 32% higher yields (P = 0.004) compared with relay-cropped eggplants, and eggplant yield decreased with later planting dates (P < 0.001). A partial budget analysis showed that transplant dates of 4 and 18 Jan. for eggplants with strawberries resulted in increased profits of $7320 and $3461 per ha, respectively, over the baseline treatment of strawberries alone, but later planting dates resulted in an overall economic loss ($7800–$16,000/ha). Strawberry termination dates did not affect eggplant yields. In conclusion, relay cropping eggplants with strawberries resulted in no effect on strawberry yields, reduced eggplant yields, but increased overall profits when eggplant were transplanted in early to mid-January. Relay cropping of strawberries with eggplants in early February to early March is less profitable than a monocrop of strawberries.

Open access

Ravneet K. Sandhu, Nathan S. Boyd, Lincoln Zotarelli, Shinsuke Agehara, and Natalia Peres

Florida vegetable growers are facing high production costs due to high input costs, lower profitability, and competition from foreign markets. Multi/intercropping allows growers to increase the yields and profits per unit area by producing multiple crops on the same beds. Experiments determining the effects of intercropping and plant spacing was conducted in Fall 2018 and 2019 at Gulf Coast Research and Education Center, Balm. Tomato and bell pepper were intercropped at low and high planting density on plastic-covered beds. Bell pepper shoot biomass was significantly (P < 0.001) reduced when intercropped with tomato, compared with monocropped bell pepper. However, tomato shoot biomass was significantly reduced when tomato plant density increased, but it was unaffected by bell pepper intercropping. Biomass of both crops was unaffected by relay cropping. Bell pepper yields when intercropped with tomato at low density (60 cm tomato-tomato and 38 cm pepper-pepper) had similar yields to bell pepper planted alone in low and high planting density. We concluded that bell pepper plants were more sensitive to interspecific competition, whereas tomato plants were more sensitive to intraspecific competition. Intercropping may be a viable option for growers at recommended plant densities used for monocrops. However, high plant density is not recommended.

Open access

Ravneet K. Sandhu, Nathan S. Boyd, Lincoln Zotarelli, Shinsuke Agehara, and Natalia Peres

Vegetable growers in Florida face rising production costs, reduced crop value, and competition from foreign markets. Relay cropping is a variant of double cropping, where the second crop is planted into the first crop before the harvest is finished. This cropping system may be a potential solution to lower production costs per crop by sharing some inputs for two crops. The objectives of this study were to determine the effect of cropping sequence and transplanting date of the secondary crop when relay cropping tomato and bell pepper. Two field experiments were conducted at the Gulf Coast Research and Education Center in Balm, FL, in 2018 and 2019. In the first experiment, tomato was grown as the primary crop and bell pepper was added as the secondary crop, with multiple transplanting dates (8 Aug., 23 Aug., 7 Sept., and 24 Sept.). The second experiment had the same setup but the reverse cropping sequence. Bell pepper yield as the secondary crop was reduced by 65% when grown with tomato as the primary crop compared with bell pepper planted alone. Transplanting date had no effect on bell pepper yield (P = 0.091). Tomato yield was unaffected by the presence of the secondary crop. In the second experiment, tomato yield as a secondary crop was 36% lower when grown with bell pepper as the primary crop compared with tomato crop alone (monocropped). However, tomato yield was significantly reduced by the presence of bell pepper only when tomato crop was planted within 30 to 45 days after planting bell pepper. Based on these results, we recommend relay cropping tomato as the secondary crop within 30 days of planting of bell pepper as the primary crop. However, we do not recommend relay cropping bell pepper as the secondary crop with tomato.