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Jialin Yu, Nathan S. Boyd and Zhengfei Guan

Many strawberry growers in Florida relay crop vegetables with strawberries or grow multiple crops on the same plastic mulch. The practice can reduce the overall input costs per crop but weed management can be problematic. Field experiments designed as a split plot were conducted in Balm and Dover, FL over two successive strawberry-growing seasons from Oct. 2014 to Mar. 2015 (year 1) and Oct. 2015 to Mar. 2016 (year 2) and two successive muskmelon-growing seasons from March to July 2015 (year 1) and March to July 2016 (year 2). The objectives were to examine the effect of summer fallow programs and the presence or absence of a relay-crop on weed density and strawberry (Fragaria ×ananassa Duchesne) and muskmelon (Cucumis melo L.) yields. Summer fallow programs included leaving the plastic mulch in place and reusing it in year 2, a sunn hemp (Crotalaria juncea L.) cover crop, or a conventional chemical fallow. Relay cropping muskmelon with strawberries had no effect on strawberry yield. Summer fallow programs had no effect on muskmelon growth and yield in Balm and Dover, as well as strawberry growth and yield in Balm. In Dover, the plastic mulch summer fallow had 22% to 34% lower berry yield in year 2 compared with cover crop and chemical fallow, respectively. In year 2, relay-cropping was more effective in reducing total weed density compared with strawberry monoculture in Dover but not in Balm. In year 2 in Dover, averaged overall summer fallow programs, the total weed density was ≈3-fold less in relay-cropping than strawberry monoculture. Of all the summer fallow programs evaluated, leaving the plastic mulch in place combined with glyphosate was the most effective summer fallow program, whereas the conventional chemical fallow was the least effective at weed suppression. We conclude that relay cropping or double use of plastic mulch for successive strawberry crops are viable options for Florida strawberry growers.

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Sheng Li, Feng Wu, Yongping Duan, Ariel Singerman and Zhengfei Guan

Citrus huanglongbing (HLB), or greening, is the most destructive citrus disease worldwide and is threatening the sustainability of the industry in major citrus-growing regions. Various treatments have been proposed in the literature to manage the disease. We review such literature and conduct an economic analysis based on the reported treatment effects on fruit yield and quality to identify cost-effective management strategies. Our results suggest that, among the treatments we reviewed, broad-spectrum insecticides provide the only cost-effective strategy for mitigating the impact of the disease. Our findings and discussion should help growers, policymakers, and other stakeholders make informed decisions in the search for effective, sustainable, and environmentally friendly treatments and policies against HLB.

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.