A Soil Temperature/Short-Wave Radiation Growth Model for Butterhead Lettuce Under Protected Cultivation in Flanders

Salomez, Joost; Hofman, Georges

doi:10.1080/01904160601171629

Cited by 8 publications

(4 citation statements)

References 47 publications

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“…In 2017, shredded leaf mulch plots had the coldest root zone temperature; however, in 2019, the bare ground plots had the lowest root zone temperature ( Table 2). The lettuce growth rate is highly correlated with both accumulated soil degree days (SDD) and accumulated photosynthetically active radiation (PAR); the growth rate is exponential, especially in the heading stage (Salomez and Hofman, 2007;Wurr et al, 1981). Higher soil temperatures accelerate leaf enlargement and development and assist the crop in reaching the maximum leaf area quickly (Dufault et al, 2009).…”

Section: Resultsmentioning

confidence: 99%

Compost and Black Polyethylene Mulches Improve Spring Production of Romaine Lettuce in Southern New England

Gheshm

Brown

2020

hortte

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Romaine lettuce (Lactuca sativa) is the most popular leafy vegetable in the United States. Organic and synthetic mulch materials are applied by farmers to reduce their weeding expenditures, manage soil temperatures, and increase the yield and quality of their crops. This study examined the impacts of using black polyethylene, compost, and shredded leaves as surface mulches in spring open field romaine lettuce by using data regarding the soil temperature, lettuce growth, and yield parameters. Mulch treatments were compared to determine effects on soil temperature, lettuce growth rates, leaf area index (LAI), yield, and plant size. Experiments were conducted in 2017 and 2019. Soil temperatures were slightly (but significantly) warmer in 2019, the plants grew more rapidly, and LAI, yield, and plant size were all significantly greater than they were in 2017. Mean soil temperatures were 18.0 and 18.9 °C in black polyethylene mulched plots, 17.7 and 18.5 °C in compost, 17.5 and 17.0 °C in bare ground, and 16.9 and 17.3 °C in shredded leaf plots in 2017 and 2019, respectively. Changes in canopy size presented a similar trend over the growing season for all treatments; shredded leaf and bare ground treatments on all measuring dates had the smallest canopy size, and compost and black polyethylene mulches had the largest canopy sizes. Black polyethylene and compost mulches had the highest LAI and yields in both years. In 2017, the bare ground treatment was similar to black polyethylene and compost mulch treatments for both parameters, and all three treatments were significantly greater than the shredded leaf mulch treatment. In 2019, the bare ground treatment was similar to the shredded leaf mulch treatment and significantly lower than the black polyethylene and compost mulch treatments. In 2017, black polyethylene and compost mulches had LAI of 7.67 and 7.37 and yields of 6.38 and 6.68 kg·m−2, respectively. Bare ground had an LAI of 7.16 and yielded 5.94 kg·m−2. Shredded leaf mulch plots had the lowest LAI (5.94) and yield (4.96 kg·m−2). In 2019, the bare ground treatment had an LAI of 7.5 and yielded 7.6 kg·m−2. Black polyethylene and compost mulches increased LAI by 1.7. Yield increased by 2.8 kg·m−2 with black polyethylene mulch and by 2.4 kg·m−2 with compost mulch. Shredded leaf mulch produced LAI and yield similar to but slightly lower than bare ground. Dry weight, plant height, and head diameter in bare ground and shredded leaf mulch treatments were significantly smaller than in black polyethylene and compost mulch treatments. The cultivar rank order was consistent across treatments in both years; ‘Ridgeline’ grew significantly faster than ‘Coastal Star’, and plants were significantly larger at harvest. Black polyethylene suppresses weeds and increases soil temperatures, thereby enhancing yields of spring-to-summer romaine lettuce under southern New England conditions. Compost mulch has similar effects on yields. Shredded leaf mulch is effective at suppressing weeds but decreases soil temperatures and yields.

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Section: Resultsmentioning

confidence: 99%

Compost and Black Polyethylene Mulches Improve Spring Production of Romaine Lettuce in Southern New England

Gheshm

Brown

2020

hortte

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“…Other researchers have increased lettuce yields in late fall and early spring by using electric soil heating cables to raise root zone temperatures (Bumgarner et al, 2011;Hunter, 2010). The lettuce growth rate is highly correlated to both accumulated growing degree days (GDD) at the soil surface and accumulated photosynthetically active radiation (PAR), and once heading has been initiated, the growth response is exponential (Salomez and Hofman, 2007). In the fall experiment, solar radiation levels dropped below 10 MJÁm -2 Ád -1 4 weeks after the lettuce was transplanted, so for much of the head formation and filling stage, accumulation of GDD at the soil surface was the primary driver of growth.…”

Section: Resultsmentioning

confidence: 99%

Organic Mulch Effects on High Tunnel Lettuce in Southern New England

Gheshm¹,

Brown²

2018

hortte

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Lettuce (Lactuca sativa L.) is a popular crop for spring and fall high tunnels among direct-market vegetable producers. Common practices include the use of compost as a soil amendment, and reliance on cultivation for weed control. This study examined the impacts of using compost as a surface mulch to control weeds in spring and fall romaine lettuce, with data collected on soil temperature, weed suppression, and lettuce yields. Costs of all inputs, including labor, were tracked to assess economic feasibility of using mulch. Compost mulch was compared with bare ground with cultivation across four cultivars of romaine lettuce: Ridgeline, Coastal Star, Green Forest, and Shushan. In the fall experiment, mulching increased average soil temperature by 1 °C and canopy cover, leaf area index (LAI), and fresh and dry weights were significantly higher in mulched plots. Mulching decreased daily variation in soil temperature in the spring experiment but had no effect on average soil temperature. Canopy cover, LAI, and fresh and dry weights were not significantly affected by mulching in the spring experiment. Compost mulch affected all cultivars similarly in both experiments, with no significant interaction effects. Yields were greater and leaves were larger in the spring experiment than in the fall for all cultivars. Fresh weight yields in the spring experiment averaged 3.22 kg·m−2 and heads had a LAI of 7.9 as compared with 1.02 kg·m−2 and 1.6 for the fall experiment. Dry matter content (DMC) was significantly higher in the fall lettuce (113 g·kg−1) than in the spring lettuce (43 g·kg−1). Cultivar rank order was consistent across experiments, with ‘Ridgeline’ having the best performance and ‘Green Forest’ the worst. ‘Coastal Star’ and ‘Shoshone’ were intermediate and very similar to each other. Although the use of compost as a mulch increased yields of all cultivars in the fall experiment, only the top cultivar, Ridgeline, produced enough additional yield to offset the increased costs of the compost mulch used in this study. The use of a less-expensive compost or a higher retail price for romaine lettuce would have made the economics more favorable for the other cultivars.

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“…Bierhuizen et al (1973) showed that shoot dry weight of lettuce was linearly related to radiation corrected for soil cover and leaf area growth was related to degree days. Additive Gomperz functions in soil temperature and radiation correlated with head weight better than either factor alone (Salomez and Hofman, 2007). The rate of photosynthesis of lettuce increased with light intensity (Park and Yong Beom, 2001).…”

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confidence: 88%

Factors Affecting Relative Growth Rate of Lettuce and Spinach in Hydroponics in a Greenhouse

Gent¹

2017

horts

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Relative growth rate (RGR), the relative increase in weight per day, can analyze the effect of environment and nutrition on growth. I examined which of the parameters responding to plant growth scaled according to RGR for lettuce and spinach grown in heated greenhouses in hydroponics with control of the nutrient solution. The experiments for lettuce in 2006–08 included all times of year, high vs. low temperature, and effect of withdrawal of nitrogen. There were four parameters that were significant in multiple linear regression vs. RGR; irradiance divided by leaf area index if it was greater than one, or normalized daily light integral (NDLI), solution temperature, electrical conductivity (EC), and logarithm solution nitrate when it was between 3 and 55 mg·L−1 N. NDLI had the most significant coefficient, but the other parameters had regression coefficients more than three times se. For experiments on spinach in 2009–10, all the parameters mentioned previously were significant in multiple linear regression vs. RGR, except EC. The coefficient for NDLI in spinach was about half the value in lettuce. The coefficients for solution temperature and low nitrate were two and three times that in lettuce. In a third set of experiments on lettuce in 1996–98, solution temperature was the only significant parameter among those mentioned previously. The coefficient for solution temperature was similar to that for regression of lettuce in 2006–08.

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A Soil Temperature/Short-Wave Radiation Growth Model for Butterhead Lettuce Under Protected Cultivation in Flanders

Cited by 8 publications

References 47 publications

Compost and Black Polyethylene Mulches Improve Spring Production of Romaine Lettuce in Southern New England

Compost and Black Polyethylene Mulches Improve Spring Production of Romaine Lettuce in Southern New England

Organic Mulch Effects on High Tunnel Lettuce in Southern New England

Factors Affecting Relative Growth Rate of Lettuce and Spinach in Hydroponics in a Greenhouse

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