Enhancing Early Spring Microclimate to Increase Carbon Resources and Productivity in June-bearing Strawberry

Abstract

<jats:p>Effects of early spring cultural practices and microclimate manipulation on `Jewel' strawberry (<jats:italic>Fragaria ×ananassa</jats:italic> Duch.) plant development, carbohydrate reserves, and productivity were measured in the field and under simulated early spring conditions in growth chambers. With traditional winter straw mulching practices of the northeastern and midwestern United States, starch content of overwintering leaves, crowns, and roots in the field declined by 51%, 78% and 69%, respectively, during late winter and early spring. There was also a net loss in root biomass over winter and no new leaf growth before mid-April, suggesting that carbohydrate reserves could be limiting plant performance during the critical early growth and flowering phase in spring. In growth chambers, exposure to CO<jats:sub>2</jats:sub> levels between 700 to 1000 mL·L<jats:sup>-1</jats:sup> significantly increased photosynthetic rates of overwintering and spring leaves compared to ambient CO<jats:sub>2</jats:sub> levels. Elevated CO<jats:sub>2</jats:sub> in growth chambers also accelerated flower development, reduced depletion of starch reserves in roots, and increased starch accumulation in crowns. In the field, early removal of straw and application of spunbonded rowcover accelerated plant development, increased starch accumulation in the leaves, and increased photosynthetic rates of overwintering and spring leaves. Elevating the CO<jats:sub>2</jats:sub> levels under rowcover further increased photosynthetic rates and advanced plant development and starch accumulation, but not significantly above rowcover alone. Carbohydrate losses later in the season during flower development were reduced when rowcover was applied in early spring. Total fruit yield was as much as 48% higher for plants under rowcover in early spring than those that had no cover and an additional 9% higher when CO<jats:sub>2</jats:sub> was elevated. Yield improvements were attributed mostly to an increase in the number of marketable secondary and tertiary fruit than to an increase in mean fruit size. The economics of rowcover use is favorable if the material is reused. The added expense of CO<jats:sub>2</jats:sub> gas and the resulting marginal gains would not make field CO<jats:sub>2</jats:sub> enrichment an economically viable practice for strawberry growers using the method herein.</jats:p>

Relationship Between the Levels of Non-structural Carbohydrates, Digging Date, Nursery-growing Environment, and Chilling in Strawberry Transplants in a Subtropical Environment

“…The concentration of non-structural carbohydrates in strawberry plants has been described in various terms, including starch (Bushway and Pritts, 2002;Pertuzé et al, 2006), soluble sugars (Ohi et al, 1995), or starch and soluble sugars (Gagnon et al, 1990;Kirschbaum et al, 1998;Lieten, 1997;Lieten et al, 1995). Sometimes several individual sugars are listed (Nishizawa, 1994;Nishizawa and Shishido, 1998;Nishizawa et al, 1997;Ruan et al, 2009).…”

Carbon and Nitrogen Reserves in Perennial Strawberry Affect Plant Growth and Yield

“…At the end of the growing season before the onset of dormancy, many deciduous plants, including perennial strawberries, accumulate carbohydrates and nitrogen (N) and use these reserves to support initial growth in the spring (Bushway and Pritts, 2001;Titus and Kang, 1982;Tromp, 1983). Nonstructural carbohydrates constitute the bulk of the total carbon (C) reserves, whereas N in the form of proteins and amino acids usually represents less than 4% of the dry matter in a strawberry plant (Marschner, 1986;Mengel and Kirkby, 1987).…”

“…Nonstructural carbohydrates constitute the bulk of the total carbon (C) reserves, whereas N in the form of proteins and amino acids usually represents less than 4% of the dry matter in a strawberry plant (Marschner, 1986;Mengel and Kirkby, 1987). As spring growth begins, both reserve carbohydrate (Bushway and Pritts, 2001;Priestley, 1960;Worley, 1979a) and N concentrations (Taylor, 1967;Tromp, 1983) decrease.…”

“…Carbohydrate status also can be increased directly through exposure of plants to elevated levels of CO 2 . Exposure to high CO 2 stimulates net C assimilation and leads to an increase in carbohydrate levels in leaves (Bushway and Pritts, 2001;Chen et al, 1997a). Yields might be enhanced if increases in CO 2 assimilation rates could be sustained during critical phenological stages, for example, during strawberry flower induction (September) or at the time of fruit filling (June to July).…”

Evaluation of methods to control Phytonemus pallidus and Anthonomus rubi in organic strawberry production

“…The combination of fleece and pyrethrum was the only treatment in this experiment that had a positive effect on the yield, but this effect was only present in Honeoye. There are well-known plant growth-enhancing effects of fleece (Bushway and Pritts 2002) that could have increased the yield but in addition to that, the treatments also decreased the number of damaged buds significantly. The variation in response between the two cultivars may be explained by differences in flowering period, because Honeoye flowers approximately 1 week earlier than Cavendish.…”