Highbush blueberry plants require low-pH, well-drained sandy soils. To increase the range of sites available for highbush blueberry production, by-products were tested as constituents in soilless media and as soil amendments. By-products, including coal ash, municipal biosolid compost, leaf compost, and acid peat, were combined in different proportions and compared to Berryland sand (alone) and Manor clay loam (alone and compost-amended) for a total of 10 media treatments. The pH of all treatment media was adjusted to 4.5 with sulfur. One-year-old tissue-cultured plants of `Bluecrop' and `Sierra' were planted in 15-L pots containing the pH-adjusted treatment media in 1997, producing their first substantial crop in 1999. For the 1999 crop, ripe fruit was harvested at weekly intervals over 5 weeks. ANOVA for yield indicated a significant cultivar × media interaction. `Bluecrop' appeared more sensitive to media treatment as yields on Manor clay loam were 80% less than on Berryland sand. Yields of `Bluecrop' on coal ash-compost mixes were similar to that of Berryland sand, and 1:1 coal ash:compost mixes produced significantly higher yields than did the 3:1 mixes. Yield of `Sierra' on Manor clay loam was 41% less than on Berryland sand, and plants growing on soilless mixes yielded 17% to 58% more than those on Berryland sand. `Bluecrop' fruit size was greatest for Berryland sand, but did not differ significantly among coal ash-compost mixes. For all media treatments, `Sierra' fruit size was inversely correlated with yield. Fruit from `Bluecrop' plants on coal ash-compost mixes ripened slightly earlier than on Berryland sand, but ripening date of `Sierra' did not vary significantly with soil treatment. The potential for employing these by-product mixes in small-scale commercial blueberry production will be discussed.
Brent L. Black and Richard H. Zimmerman
Richard H. Zimmerman
Highbush blueberry is adapted to well-drained sandy soils containing some organic matter, but these are often unavailable in many areas where blueberry production is desired. I tested the concept of using freely available by-products to produce an artificial medium for growing blueberries. In June 1997, 1-year-old tissue-cultured plants of `Bluecrop' and `Sierra' blueberry were planted into 15-L plastic pots filled with soil or soilless medium in a total of 10 treatments. Soils used were Berryland sand (alone) and Manor clay loam (alone or amended with 25% or 50% compost mix 1); soilless media were composed of coal ash amended with 25% municipal biosolid compost (B), 25% leaf compost (L), 25% or 50% compost mix 1 (1 B: 1 L),\ or 25% or 50% compost mix 2 (1 compost mix 1: 1 acid peatmoss). pH of all mixes containing compost was adjusted to ≈4.5 with sulfur. After the first year, plants of both cultivars in Berryland sand had significantly more shoot growth than in any other treatment except for Manor clay loam. The least growth was produced by plants growing in Manor clay loam amended with compost mix 1 and in coal ash amended with unblended compost (B or L). After the second year, plants in the best treatments were 90 to 100 cm tall. More shoot growth was produced by plants in Berryland sand and in coal ash amended with 25% or 50% of compost mix 1, followed by plants in coal ash amended with 50% compost mix 2 or 25% compost B; plants in Manor clay loam, whether or not amended with compost, had the least growth. In 1998, 95% of the plants flowered and most set fruit, but differences among treatments were not significant. `Sierra' plants produced more growth than those of `Bluecrop' in all treatments.
Brent L. Black and Richard H. Zimmerman
Bottom ash from a coal-fired power plant and two composts were tested as components of soil-free media and as soil amendments for growing highbush blueberry (Vaccinium corymbosum L.). Combinations of ash and compost were compared to Berryland sand, and Manor clay loam, and compost amended Manor clay loam. The pH of all treatment media was adjusted to 4.5 with sulfur at the beginning of the experiment. In 1997, plants of `Bluecrop' and `Sierra' were planted in 15-dm3 pots containing the pH-adjusted treatment media. The first substantial crop was harvested in 1999. At the end of the 1999 season, one half of the plants were destructively harvested for growth analysis. The remaining plants were cropped again in 2000. Yield and fruit size data were collected in both seasons, and leaf and fruit samples were collected in 1999 for elemental analysis. The presence of coal ash or composted biosolids in the media had no detrimental effect on leaf or fruit elemental content. Total growth and yield of both cultivars was reduced in clay loam soil compared to Berryland sand, whereas growth and yield of plants in coal ash-compost was similar to or exceeded that of plants in Berryland sand.
Kristen B. Engstrom, Susan G. Myers and Bradford C. Bearce
Rooted cuttings of `Dark Red Hegg' poinsettia were potted in root media containing 0, 50, or 100 percent by volume of coal bottom ash in peat::vermiculite (50:50, v/v), one cutting per 1 liter pot. The plants were placed in a closed loop nutriculture system and irrigated with 200 mg N.liter-1 of (N-P-K) 20-8.8-17.8. 15-2.2-22.25. or 20-4.8-21.6 (commercial Hydrosol + Ca(NO3)2). each with soluble trace elements. Fertilizer solutions were maintained at pH=6.0-6.5 and E.C.=1.6-2.5 dS.m-1. Media pH and E.C. tended to increase with amount of ash in the media. The 20-8.8-17.8 fertilizer reduced pH values 0.6-0.8 in all media. Plants were of equal height in all media. Average bract cluster diameters of plants in 100 percent coal ash were reduced compared to those in 0 and 50 percent coal ash by the 15-2.2-22.25 fertilizer. but not by the other two fertilizers. Plant top dry weights in 100 percent ash were reduced below those in 0 and 50 percent ash by the 20-8.8-17.8 and the 15-2.2-22.25 fertilizers.
Rooted cuttings of Rhododedron catawbiense `Roseum Elegans' were potted on February 27, 1992, in 1 liter pots containing sphagnum peat moss:composted pine bark:sand:pinewood peelings:coal bottom ash mixed at ratios of 15:70:15:0:0, 15:70:0:0:15, 15:35:15:35:0, 15:35:0:35:15, 15:0:15:70:0 or 15:0:0:70:15 percent volume. Irrigation and fertilization frequencies were recorded from March 18-September 18, 1992. Moisture retention data showed that the high pinewood peeling mixes retained less moisture but that coal bottom ash improved moisture retention when substituted for sand in all mixes. The highest pinewood peeling:ash medium required less irrigation than the other mixes but a higher frequency of acid fertilization. The highest pine bark:sand medium required more. neutral fertilization than the other mixes. Numbers of new shoots per plant in the 15:35:15:35:0, 15:0:15:70:0 and 15:0:0:70:15 media were lower than those in the high pine bark:ash mix. Plant heights were lower in the 15:0:15:70:0 mix. Flower buds per plant were higher in the 15:35:15:35:0 medium than in the 15:70:15:0:0, 15:0:15:70:0 or the 15:0:0:70:15 plants. Leaf tissue analysis showed K and Cu to be at deficiency levels in all plants. Boron was higher in all plants grown in ash containing media. Zinc was low in plants grown in high pinewood peelings media.
Qingren Wang, Yuncong Li and Waldemar Klassen
A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on `Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudangrass (Sorghum bicolor × S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash, coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production (i.e., fruit yields were enhanced by 53% to 62% in 2002-03 and by 28% to 70% in 2003-04). Soil amendments enhanced okra fruit yields from 38.3 to 81.0 g/pot vs. 27.4 g/pot in the control in 2002-03, and from 59.9 to 124.3 g/pot vs. 52.3 g/pot in the control in 2003-04. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. Among cover crop treatments, sunn hemp showed promising improvement in concentrations of calcium (Ca), zinc (Zn), copper (Cu), iron (Fe), boron (B), and molybdenum (Mo) in fruit; magnesium (Mg), Zn, Cu, and Mo in shoots; and Mo in roots of okra. Among soil amendments, biosolids had a significant influence on most nutrients by increasing the concentrations of Zn, Cu, Fe, and Mo in the fruit; Mg, Zn, Cu, and Mo in the shoot; and Mg, Zn, and Mo in the root. Concentrations of the trace metal cadmium (Cd) were not increased significantly in either okra fruit, shoot, or root by application of these cover crops or soil amendments, but the lead (Pb) concentration was increased in the fruit by application of a high rate (205 g/pot) of biosolids. These results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.
Yuncong Li, Edward Hanlon, George O'Connor, Jianjun Chen and Maria Silveira
Florida Administrative Code 62–709.550 ( Florida Department Environmental Protection, 2009 ). Coal ash. Coal ash (fly ash and bottom ash) is solid waste regulated at the federal level using the Resource Conservation and Recovery Act (RCRA) of 1976, and
James Gibson and Bradford C. Bearce
Poinsettia (Euphorbia pulcherrima Willd. Ex Klotsch) cultivars `Dynasty Red', Nutcracker Pink', and `Annette Hegg Topwhite' were planted in 15-cm azalea pots containing peat: vermiculite (1:1, v:v) in which coal bottom ash sieved through 6-mm mesh was mixed in proportions of 0%, 25%, or 50% by volume. Planting date was 23 July 1996, and pinch date was 25 Aug. Harvest date at anthesis was 16 Dec. Plant heights of all cultivars were increased in the ash media. L, a, and b, values measured with a Minolta CR-200 chroma meter differed very slightly among ash levels within cultivars. Mean per plant bract cluster count was very similar among ash levels and cultivars. Mean diameter of largest bract cluster was increased above that of 0% coal ash plants for `Topwhite' plants in 50% coal ash media. Mean per plant dry weights of all three cultivars were increased over those of control plants in both 25% and 50% coal ash media. Media pH increased with increase in ash, while EC tended to decrease. Media available Ca increased with ash increase, while Mg decreased and the same pattern was noted for leaf tissue Ca and Mg. This was probably due to release of Ca from the ash, which contains about 10% Ca oxides. Tissue levels of Ca and Mg were within acceptable ranges; however, K levels also declined in plant tissue to suboptimal levels with plants in ash media.
Mark D. Sherratt, Donna V. Coffindaffer-Ballard and Bradford C. Bearce
Four poinsettia cultivars were planted in root media containing 0%, 25%, or 50% (by volume) of coal bottom ash or aged hardwood sawdust. Bract color development in `Supjibi' was delayed in media containing sawdust or ash by up to 8–12 days. Bract color initiation of `Jingle Bells' and `Success' occurred earliest in media containing 25% sawdust, but color development was delayed in 50% coal ash. Color development in `Dark Red Hegg' was not affected by ash or sawdust. Analysis of combined leaves from all four cultivars showed Fe levels below normal where media contained sawdust. Leaf Mo concentrations increased with increased media sawdust to above the normal range, but Mn levels were below the normal range in sawdust media. Leaf Ca levels were below normal in all media, possibly due to excessively high K levels in media and leaves. When fertilizer concentration and frequency were adjusted to media EC levels, control media (0% ash or sawdust) required 100 ppm N once a week. Media containing sawdust required 300 ppm to maintain EC levels between 1.25–2.25 dS·m–1 and coal ash media were irrigated with water following the sixth week after planting due to EC levels >2.25.
Dharmalingam S. Pitchay and B.C. Bearce
Rooted cuttings of `Supjibi' poinsettia were potted in peat vermiculite, mixed with coal bottom ash at 0%, 25%, 50%, 75%, or 100% by volume. Values of pH were higher in media containing coal bottom ash. In general, pH increased for the first 4 weeks, during which time 50–100 ppm (N) fertilizer was being applied, decreased temporarily when 200 ppm fertilizer began, and then increased and stabilized for the last 5 weeks. At first, pH tended to be higher with increase in ash, but when 200 ppm fertilizer was begun, pH became the same in all coal ash levels. Once fertilization was stopped, pH tended again to be higher in ash media. Levels of EC remained low in all media when 50–100 ppm of fertilizer was applied, but increased after 200 ppm fertilizer was begun, increasing to excessive levels 2 weeks later. With more watering, EC declined in the 0% ash, but remained high in 50% to 100% ash media. Leaf Ca content increased with increase in media ash but was below the normal range in all plants. With increase in media ash, water capacity decreased, but bulk density increased. Bract color development in plants in ash media appeared delayed.