Bare Root Research Articles

Cell size in trays for the production of strawberry plug transplants

The objective of this work was to evaluate the influence of cell sizes used for strawberry plug production in trays compared to bare root transplants, regarding initial plant size, harvest timing, and total strawberry fruit yield. Plug transplants were produced from runner tips rooted in trays with cell sizes of 26.5, 50, 100 and 150 cm³ filled with Plantmax HA organic substrate. Bare root transplants (control) were produced in a closed soilless system using sand as substrate. A randomized block design was used, with four replicates with 16 plants per plot. Bare root transplants and plug transplants from 100-cm³ cells had larger crown and higher leaf and root dry mass. Early fruit yield was higher in plants propagated from plugs than in those propagated from bare root transplants. Spring and total fruit yield did not differ among treatments, with an average yield of 435 and 874 g per plant, respectively. Earlier strawberry fruit yield was obtained by using plug transplants, even from trays with small cells of 26.5 or 50 cm³.

Efficacy of highland production of strawberry transplants

This study was conducted to evaluate the effect of propagation environment (high and low elevation) on runner productivity and quality of ‘Maehyang’ and ‘Red Pearl’ strawberry cultivars. Two propagation methods (bare root plants and plug plants) were used for both environments. Regardless of cultivar or propagation method, runners produced at high-elevation had significantly greater crown diameter, and root and whole plant dry weights, and carbohydrate accumulation tended to be greater in runners from the highland. The high elevation site was more effective for producing high quality strawberry runners than the low-elevation site.

Evaluation of Clay Aggregates in Perennial Offshoot Production

Abstract In an effort to compare yield and time required to remove substrate from roots of liners, Ophiopogon japonicus and Ophiopogon japonicus ‘Nana’ (lilyturf) bare root bibs were potted into 100% aged pine bark, 8: 2 (v: v) pine bark: peat moss, 100% perlite, 100% fine grade Profile™ porous ceramic (Profile™ products LLC, Buffalo Grove, IL), or 100% course grade Profile™ porous ceramic. In a second study Ophiopogon japonicus was potted into 100% aged pine bark, 100% 3/16-inch HydRocks® (Big River Industries Alpharetta, GA), fine grade 100% Profile™, 100% perlite, 100% sand, 8: 2 (v: v) pine bark: peat moss, and 3: 1 (v: v) 3/16 HydRocks®: sand. In the second study, fine grade Profile™ produced the highest number of total bibs per container and bib production was similar to 8: 2 pine bark: peat moss. HydRocks® was similar to pine bark in total bibs per container but was more efficiently removed from roots. Removal of the HydRocks® substrate from plant roots required 50% less time than removal of pine bark: peat moss substrate and 51% less time than removal of pine bark substrate. HydRocks® took 23% less time to remove from roots than fine grade Profile™. Results indicate that clay materials such as HydRocks® and Profile™, when compared to conventional substrates can provide suitable yields while also decreasing labor cost by decreasing time to bare-root.

Occurrence and pathogenicity of fungi in necrotic and non-symptomatic shoots of declining common ash (Fraxinus excelsior) in Sweden

Currently, massive dieback of Fraxinus excelsior is observed in countries of eastern, northern and central Europe, and the reasons for it are unclear. The aims of the present work were (a) to study fungal communities in declining F. excelsior crowns; (b) to clarify role of fungi in the decline. Shoots from symptomatic crowns were collected in four localities in central Sweden, and distributed into the following categories: (a) visually healthy; (b) initial necroses; (c) advanced necroses; (c) dead tops. The most frequently isolated fungi were Gibberella avenacea, Alternaria alternata, Epicoccum nigrum, Botryosphaeria stevensii, Valsa sp., Lewia sp., Aureobasidium pullulans and Phomopsis sp., and these taxa were consistently found in shoots of all four symptomatic categories. Forty-eight taxa of other fungi were isolated, and fungal diversity was not exhausted by the sampling effort. The same taxa of fungi were dominant in F. excelsior shoots of different symptomatic categories, and moderate to high similarity of fungal communities was observed in shoots despite the symptoms. Forty-four isolates from 24 fungal taxa were used for artificial inoculations of 277 1-year-old F. excelsior seedlings in bare root nursery. After 2 years, only four fungi caused symptomatic necroses of bark and cambium: A. alternata, E. nigrum, Chalara fraxinea and Phomopsis sp. The most pathogenic was C. fraxinea, inducing symptoms on 50% of inoculated trees, while three other fungi caused necroses on 3–17% of inoculated trees. Infection biology of C. fraxinea and environmental factors determining susceptibility of F. excelsior to decline deserve future investigations.

Nitrogen and Substrate Assessment For Pot-in-Pot Production in the Intermountain West

Abstract We investigated optimum nitrogen rates and different growth substrates for short-term finish production of container and bare root shade tree liners in a pot-in-pot production system in the Intermountain West. In one study, nitrogen ranging from 0–27 g N-tree−1 (0–36 lbs N·1000 ft−2) as urea was applied to quaking aspen (Populus tremuloides), ‘Autumn Blaze’ maple (Acer × freemannii ‘Autumn Blaze’), ‘Chanticleer’ flowering pear (Pyrus calleryana ‘Chanticleer’), and ‘Canada Red’ chokecherry (Prunus virginiana ‘Canada Red’). Twenty-six liter liners (#7 container) were transplanted into 57 liter (#15) containers in a retail nursery finishing pot-in-pot system. Trunk diameter growth and shoot-tip elongation measurements were recorded for one growing season. Overall, only pear had a consistent increase in terminal shoot and trunk growth in response to N at 9 g N·tree−1 (12 lbs N·1000 ft−2). Maple and chokecherry exhibited modest lateral shoot growth at 4.5 and 18 g N·tree−1 (10–24 lbs N·1000 ft−2), and aspen growth had no response to N. The second study evaluated the effect of nitrogen rates and substrate type on first-year trunk diameter growth of bare root common chokecherry (Prunus virginiana) and Aristocrat flowering pear (Pyrus calleryana ‘Aristocrat’). Large bare-root liners were installed into a finishing pot-in-pot system with three substrate treatments, a proprietary, a commercial mix using several organic matter sources, and a simple composted bark-pumice mix. Five nitrogen rates, 0–9 g N·tree−1, (0–12 lbs N·1000 ft−2) were applied to each substrate. Pear again had a modest increase in trunk growth at 2.2 g N per tree, but had no response to the different growth substrates. Chokecherry trunk growth did not increase with nitrogen nor did substrate treatment substantively affect growth. This study indicates that Intermountain West retail nurseries can likely reduce first-year nitrogen applications to container and bare root liner stock during finish production, and use a simpler media to achieve optimum growth at potentially lower cost.

Closed soilless growing system for producing strawberry bare root transplants and runner tips

The objective of this work was to test a closed soilless growing system for producing bare root transplants and runner tips of two strawberry clones, using two categories of substrates. The system used corrugated roofing panels of fiber-cement, over which a substrate layer was used as a growing bed. The nutrient solution was pumped from a reservoir toward the upper end of the roofing panels and drained back to a reservoir. Plant growth and development were determined for two advanced strawberry clones, grown in sand or in Plantmax organic substrate. Growth of the stock plants and the number and dry mass of bare root transplants were similar in the substrates, but bare roots differed in their crown diameters by substrate. For number of runner tips, no significant differences were found in total, small, and medium categories in the substrates. A mean production of about 590 runner tips per square meter and 145 bare root transplants per square meter was obtained. For both clones, a large number of bare root transplants and runner tips of adequate size were produced in the closed soilless growing system using sand or organic substrate.

Stock Type, Subsoiling, and Density Impact Productivity and Land Value of a Droughty Site

Abstract Management practices that overcome low seedling survival and poor tree growth of well-drained, droughty sites can improve their productivity and profitability. This study was established to explore tree and stand growth trends, potential forest product yields, and land expectation values of loblolly pine on a droughty site in response to (1) seedling stock type, (2) subsoiling, and (3) stand density regime. In winter 1993, container (CONT) and bareroot (BARE) seedlings were planted with or without subsoiling at 746 trees per hectare (TPH). BARE seedlings were planted without subsoiling at 1,493 TPH to provide a comparison between low-density treatment combinations and a conventional (CONV) management regime for this site type. Tree growth was monitored periodically through age 13 years. Yield trajectories were estimated by predicting forest product yields with FASTLOB using age 13 years stand characteristics, and land expectation value was determined from revenue predictions and costs associated with each treatment. Low-density regimes that included CONT seedlings or subsoiling before BARE seedling planting improved tree growth through midrotation and had yield estimates comparable with that of a CONV regime. However, land expectation values associated with subsoiling were lower than those of low-density CONT and CONV regimes because of its cost and negligible benefits for seedling survival.

Regional Analysis of Production Practices and Technology Use in the U.S. Nursery Industry

The National Nursery Survey has been conducted four times at 5-year intervals (1988, 1993, 1998, and 2003) by a multistate research committee on economics and marketing to help fill the void of publicly available information on management characteristics of the nursery industry. For the first time in 2003, the National Nursery Survey was conducted using a standard sampling methodology with 15,588 total firms representing 44 states. The objective of this study was to provide a regional analysis of nursery production practices, because production practices and technology use may differ across regions in response to varying economic and environmental conditions. From analysis of the 2485 returned surveys, firms in the northern and interior regions of the country with more seasonal activity made greater use of temporary labor. Containerized growing systems were the predominant system throughout the United States; however, firms in the Southeast, South Central, and Pacific coast regions used this system to a greater degree, whereas firms in other regions also commonly used bare root and balled and burlapped systems. Nurseries in the Southeast region, with a warmer climate, used Integrated Pest Management practices more prevalently. Most regions had a significant share of total production from native American plants, approaching or exceeding 20% of total sales, except the Pacific region. In some regions, forward-contracting accounted for a significantly higher share of total sales, perhaps indicating greater aversion to market risk. The Mountain region stood out for its high level of adoption of computer technologies for production, marketing, and management. Data on water use and irrigation technology did not indicate any clear pattern with respect to regional differences in relation to water scarcity.

Amending a Gravel Based Growing Medium with Calcined Clay Improves Physical Properties and Seedling Growth

Abstract The Missouri Gravel Bed (MGB) is a system that uses pea gravel with 10% sand (v/v) as a root growth medium, allowing plants to be removed from the gravel and planted, bare root, during the growing season. However, the low water holding capacity of the medium necessitates frequent irrigation. This study was conducted to determine the effects of amending pea gravel with calcined clay (Terra-Green®) on the physical properties of the medium and on growth of Gymnocladus dioicus (L.) K. Koch seedlings. Adding 10% sand (v/v) increased water holding capacity of the medium slightly at water tensions above 1 kPa. Gravel amended with 40% calcined clay had 16% air-filled porosity and had 3.5 times more plant available water than gravel with sand only. Dry weights of seedlings grown in gravel amended with 40% calcined clay and no sand were over twice as great as those of seedlings grown in the standard MGB medium.

Efecto del sistema y densidad de la almaciguera en el cultivo de cebolla (Allium cepa)

C. Gomez, and C. Oberpaur. 2007. Effect of density and seedbed system in onion (Allium ( cepa) production. Cien. Inv. Agr. 34(3):205-214. Production of onion (Allium cepa) seedlings for transplants is done directly in fl at soil conditions or in trays using reduced cell volumes and high plant density conditions, without consideration of the possible effect that reduced cell volume can have on crop growth. Therefore, the objective of this study was to evaluate the production of onion seedlings in two seedbed systems and their subsequent behavior in the fi eld. Seedling production and transplant establishment were determined with a long-day type of onion (cv. Grano de Oro) in the Metropolitan Region of Chile (33°-34° south latitude) from 2004 to 2005. The production of covered root transplants was performed in trays with 286 (18 cm 3 ), 432 (10 cm 3 ) and 814 (5 cm 3 ) cells each, equivalent to plant densities of 1144 (low), 1728 (medium) and 3256 (high) plants·m -2 , respectively. The production of bare root transplants was done in boxes with equal plant densities as in the tray system. Next, plants obtained from each seedbed system and plant density were fi eld transplanted. Based on the results obtained, neither plant density nor transplant production system affected the pseudo stem diameter 25 days after emergency (DAE). At 77 DAE, the pseudo stem diameters were 3.8 and 5.2 mm, the root dry weights (DW) were 4.8 and 6.2 g·plant -1 produced in high and low plant density, respectively. This suggests that the tray system had a minor effect on plant development. At 23 days after transplanting (DAT) differences in the pseudo stem diameter between the three densities were obtained, although differences between the bare and covered root systems were not statistically signifi cant. Plants obtained from high-density seedbeds showed a smaller pseudo stem diameter and lower canopy DW than plants produced in low-density seedbeds until 84 DAT. At harvest, no differences were observed in formation or among the quality categories of the onion. Therefore, it is feasible to produce onion seedlings to be transplanted with bare roots or covered roots, produced in high-density boxes or in 5 cm 3 cells, without affecting the fi nal quality of harvested onion bulbs.

Genetic control of propagation traits in a singleCorymbia torelliana×Corymbia variegatafamily

Genetic control of vegetative propagation traits was described for a second-generation, outbred, intersectional hybrid family (N = 208) derived from two species, Corymbia torelliana (F. Muell.) K.D. Hill & L.A.S. Johnson and Corymbia variegata (F. Muell.) K.D. Hill & L.A.S. Johnson, which contrast for propagation characteristics and in their capacity to develop lignotubers. Large phenotypic variances were evident for rooting and most other propagation traits, with significant proportions attributable to differences between clones (broad-sense heritabilities 0.2–0.5). Bare root assessment of rooting rate and root quality parameters tended to have the highest heritabilities, whereas rooting percentage based on root emergence from pots and shoot production were intermediate. Root biomass and root initiation had the lowest heritabilities. Strong favourable genetic correlations were found between rooting percentage and root quality traits such as root biomass, volume, and length. Lignotuber development on a seedling was associated with low rooting and a tendency to poor root quality in cuttings and was in accord with the persistence of species parent types due to gametic phase disequilibrium. On average, nodal cuttings rooted more frequently and with higher quality root systems, but significant cutting type × genotype interaction indicated that for some clones, higher rooting rates were obtained from tips. Low germination, survival of seedlings, and rooting rates suggested strong hybrid breakdown in this family.

Growth of bare root Pinus taeda, L. seedlings cultivated under five densities in nursery

Seedlings compete for nutrients, water and light. The available area for each seedling affects their behavior related to requirements for these resources. This experiment evaluated the influence of five plant densities on the growth of bare root Pinus taeda, L. seedlings in a nursery after outplanting. The analyzed characteristics were: height (H), root collar diameter (D), H/D ratio, and dry matter weight. Higher densities stimulated H growth and the lowest densities increased D average and dry matter weight and lowered the H/D ratio. Seedlings were distributed by H, D and H/D classes. Higher densities had a larger number of seedlings in larger H classes. Larger numbers of seedlings with larger D and lower H/D ratios were found in lower densities. Ten months after outplanting the seedlings grown in lower densities had higher survival percentages and growth. Some saplings of standardized heights were uprooted with the objective of studying their root systems. The lowest densities stimulated higher numbers of first and second order roots as well as fresh and dry matter weights of thin roots with mycorrhizae presence. In both parts of the experiment, the density of 278 seedlings m-2 yielded equivalent averages as compared to the lowest densities.

Occurrence of arbuscular mycorrhizal fungi in bromeliad species from the tropical Atlantic forest biome in Brazil

The mycorrhizal status of epiphytic, rupicolous, and terrestrial bromeliad species from the Brazilian Atlantic Rain Forest has been examined. Roots of 13 species of bromeliads were analyzed for the presence of mycorrhizal structures such as arbuscules, hyphae, and vesicles as well as other fungal structures. Rhizosphere soil was sampled to identify arbuscular mycorrhizal fungal (AMF) species associated only with terrestrial bromeliad species. Most specimens collected were epiphytic bromeliads in the genera Aechmea, Bilbergia, Nidularium, Tillandsia, and Vriesea. Differentiating structures of AMF were found in only three species of bromeliads. The pattern of mycorrhizal colonization was mainly internal, and external mycelium and arbuscules were observed only in the terrestrial Nidularium procerum. Root endophytes with dark brown septate mycelium, thin external hyphae, and Rhizoctonia-like sclerotia were also detected in some root segments. A total of ten spore morphotypes were recovered from the rhizosphere of N. procerum, with Acaulospora mellea, A. foveata, and Glomus sp. being the most common species recovered. Our study demonstrated that most of the epiphytic species are not associated with AMF. We attribute this mainly to the exposed bare root conditions found in epiphytic bromeliads.

First-year growth response of cold-stored, nursery-grown aspen planting stock

This research examined the first year growth characteristics of cold stored and transplanted nursery-produced aspen (Populus tremuloides) seedlings (container and bareroot (BR)) and compared it to the growth of seedlings that had not been transplanted (established from germinants in the field) and therefore had an unrestricted root system (UR). Prior to planting, nursery-produced seedlings were placed in cold storage (−3°C) and root growth potential (RGP) and total non-structural carbohydrate (TNC) root reserves were tested at 0, 10, 75 and after 150 (container) and 190 days (BR) of storage. Both container and BR stock had much lower root to shoot ratios (RSRs) and root carbohydrate reserves compared to UR seedlings after 170 days. During storage, root reserves in container stock declined faster than in the BR and UR seedlings. RGP in all nursery stock was the highest after 75 days of storage, while longer storage resulted in shoot dieback and reduced root growth. After the first growing season, UR seedlings were one tenth the size of the nursery stock; however, in the second growing season they had no stem dieback and grew twice the height and stem diameter. The higher RSRs and root reserves in the UR seedlings was likely caused by early bud set in its first year of growth. This suggests that inducing bud set earlier in the growing regime might allow seedlings to increase root mass and carbohydrate reserves.

English

The Des-Bee-Dove Mine complex (owned by PacifiCorp and operated by Energy West Mining Company) had a long and rich mining history beginning in the 1880's. Since development of the mine surface facilities pre-dated SMCRA, initial construction did not include segregation and storage of soils. A total of approximately 13.8 hectares were disturbed prior to the commencement of reclamation in 1999. The goal of the reclamation project was to reclaim the mine site to within approximate original contour (AOC) using existing soil resources excavated on-site and achieve a diverse vegetative stand that would stabilize and protect the reclaimed slopes. Within this disturbed site, there were 14 portal openings necessitating elimination of approximately 762 meters of cut slopes. Also within this site was a 1.0 ha pad constructed into the side of steep canyon walls. This pad alone required approximately 36,000 m 3 to fill to AOC. With the cooperation of the Utah Division of Oil, Gas and Mining, a comprehensive soil management plan was developed. This plan assessed the quantity and quality of soils available for final reclamation throughout the mine site. The assessment involved excavating a series of trenches, placing them in strategic locations. These trenches were not only utilized to assess the quantity and quality of available substitute soil material, but also to ascertain the characteristics of the subsurface geology. Knowing this geology, approximate locations of natural drainages, rock faces, and drops were determined. By June 2003, approximately 215,000 m 3 of spoil and suitable soil were moved and placed to achieve the final reclaimed contour. Approximately 272 kg of native seed along with 3,500 bare root and containerized plants were manually planted. All work occurred on slopes with an approximate grade of 2 horizontal to 1 vertical. Today, three years after the completion of final reclamation, the Des-Bee-Dove Mine complex supports a broad vegetative cover that has protected and stabilized the reclaimed surface. Perennial grasses and woody plant species have begun to outnumber the exotic annuals. As desirable plant species progressively dominate the site, vegetative diversity increases significantly.

THE EFFECT OF TEMPERATURE AND PHOTOPERIOD ON THE LEAF SENESCENCE AND PARTITIONING OF ASTILBE AND PAEONIA

The effect of temperature and photoperiod on leaf senescence and partitioning were studied in Fall 2004 using Astilbe simplicifolia `praecox alba' and Paeonia hybrid `Barrington Belle' and Fall 2005 using Paeonia Paula Fay and Astilbe chinensis ×purpurea. Bare root divisions and crowns were potted and grown outdoors during the spring and summer. Plants were treated to either Ithaca fall outdoor and controlled warm (70–60 °F) environment under normal daylength (about 12 hours) or longday (LD15 hours in 2004 and 16 hours in 2005). The chlorophyll readings and senescing leaves were significantly affected by treatments in the two plants in 2004. There was no significant difference in the change in the total dry biomass in Paeonia hybrid `Barrington Belle' grown under different treatments but the number of large buds was highest in those grown at 70–60 °F at LD. Higher total plant biomass was observed over-all in Astilbe simplicifolia `praecox alba' in warmer greenhouse environment and under LD. The effect of photoperiod and its interaction with temperature were significant in weights of Astilbe simplicifolia `praecox alba' roots. Greenhouse grown plants had higher bud numbers compared to outdoor-grown plants. In 2005, Astilbe chinensis ×purpurea in the greenhouse under LD had more shoots and large buds than the other treatments. Senescing leaf and chlorophyll reading was affected by temperature and photoperiod and its interaction. Paeonia Paula Fay under LD outdoors had more large buds than those under natural photoperiod, but is similar in effect to those in the greenhouse. Results may be used to improve propagule quality, adjust crop production cycle and cultivation in different climate.

Container Size and Initial Trunk Diameter Effects Growth of Acer rubrum L. During Production

Abstract Two studies were conducted to determine container size and liner (young bare root trees) trunk diameter effects on growth of Acer rubrum L. ‘Franksred’, Red Sunset™ red maple. In experiment 1, maples liners with initial mean trunk diameters of 12.2 mm (0.5 in), 15.9 mm (0.6 in), and 22.3 mm (0.9 in) were potted in 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) containers and grown for 18 months (2 growing seasons). Height and trunk diameter growth at the end of each growing season were affected by both the initial liner trunk diameter and container size. During year 1, liners with an initial trunk diameter of 12.2 mm (0.5 in) increased 28 and 70% more in height growth compared to liners initially 15.9 mm (0.6 in) and 22.3 mm (0.9) in trunk diameter, respectively. Twenty three percent more height growth occurred with maples in 37.8 liter (#10) and 56.8 liter (#15) containers compared to those in 26.5 liter (#7) containers. Trunk diameter growth increased 50% more with 12.2 mm (0.5 in) liners compared to 22.3 mm (0.9 in) liners. A 25% increase in trunk diameter growth occurred with liners potted in 56.8 liter (#15) compared to 26.5 liter (#7) containers. At the end of the second growing season, final tree size was similar with liners that were initially 12.2 mm (0.5 in) and 15.9 mm (0.6 in) liners in trunk diameter to those initially 22.3 mm (0.9 in) when potted into 37.8 liter (#10) and 56.8 liter (#15) containers. In experiment 2, maple liners with trunk diameters 17.5 mm (0.7 in), 20.5 mm (0.8 in), and 29.0 mm (1.1 in) were potted in container sizes 26.5 liter (#7), 37.8 liter (#10), and 56.8 liter (#15) and grown for 18 months (2 growing seasons). Liners grown in 56.8 liter (#15) containers had 92% more height growth and 48% more trunk diameter growth than with liners in 26.5 liter (#7) containers. At termination, the shoot dry weight was 41% larger with maples in 56.8 liter (#15) containers compared to those grown in 26.5 liter (#7) containers.

How Much to Pay for Clonal Oil Palm

The choice of planting material has an important bearing on the profitability of a planting. This is because it is a “one off” decision and once planted, a planter has to live with it for the entire lifespan of the planting. Clonal palms have been reported to be superior to DxP hybrids in both fresh fruit bunch (FFB) yields and oil extraction rates (OER) and are sold at more than 10 times the price of the latter. The question of what is a fair price to pay for clonal palms is an issue of much debate. The net present value ratio (NPVR) between clonal palms and DxP hybrids was used to evaluate their comparative profitability. Initially, net present value (NPV) for 162 combinations comprising three levels each of clonal palm price (RM15, 20 and 30 per acclimatised bare root ramet), FFB yield, OER and palm products price (crude palm oil, CPO at RM800, 1100 and 1400 per tonne and palm kernel, PK at RM480, 660 and 840 per tonne), and two levels of discounting rates at 5 and 10 per cent. Clonal palm was assumed to be 5, 10 and 15 per cent better than DxP hybrid in both FFB yield and OER. DxP hybrid was priced at RM1 per germinated seed. At long term low CPO and PK prices (RM800 and 480 per tonne respectively), negative NPV was recorded in all but three of the 54 combinations evaluated, indicating that it is not profitable to plant either DxP hybrids or clonal palms in 94 per cent of the cases evaluated. Hence NPVR was computed for the balance of the 108 combinations at long term medium and high palm product prices only. Between DxP hybrids and clonal palms, the latter would be more profitable in 97, 94 and 81 per cent of the time at clonal palm prices of RM15, 20 and 30 respectively. Therefore, it would be worth paying a higher price for superior clonal palms in most of the cases. This is particularly true for clones with high OER as an increase in OER has a more favourable impact than a similar increase in FFB yield. This is expected as the former will lead to higher CPO yield without incurring additional harvesting and transport cost and savings in processing cost. The internal rate of return (IRR) and discounted payback period (PBP) were also computed as supporting economic criteria. At medium and high palm product prices, IRR is higher than the cut-off rate of 10% throughout with the highest value of 23.2 per cent, while PBP varied from 7 to 22 years. Keywords: Clonal oil palm versus DxP hybrid, net present value ratio, internal rate of return, payback period.

Effect of Storage Period on the Viability of Bare Root Cocoa Seedlings

An experiment to study the storage of bare root cocoa seedling may be used as an alternative technology to transport of cocoa seedling. The storage period were 2, 3 and 4 days using: Randomize Complete Design and 4 replications. Each replication was used 25 seedlings. The results showed that bare cacao seedling storage for 2, 3 and 4 days decreased wet weight 1—2 g, and leaf number 2—4. Seedling viability percentage for 2, 3 and 4 days storage was 90.00; 97.50 and 75.00% respectively.Key words :Bare root, cocoa seedling, storage, viability.

(101) Fertilizer Source Affects Nitrogen and Phosphorus Levels in Leachate from Container-grown Quercus phellos L. and Magnolia virginiana L.

Environmental concerns with nitrogen and phosphorus use at container nurseries and the subsequent effects of nutrient-laden irrigation effluent prompted this study. Bare root liners of willow oak (Quercus phellos L.) and sweetbay magnolia (Magnolia virginiana L.) were grown in #5 containers during year one and repotted into #15 containers during year two using 100% pine bark or pine bark: peat substrate (4:1 by volume). Two fertilizer sources, Osmocote 19N–2.2P–7.5K (19–5–9) or Harrell's 17N–2.2P–10.0K (17-5-12), were included in the container substrate in a fluoropolymer bag with 17 g N in each #5 container and 63 g N in each #15 container. Using a split plot design with fertilizer and media as subplots, a cyclic irrigation regime consisting of three irrigation applications spaced one hour apart was compared to a traditional irrigation regime with one irrigation application that equaled the total volume applied in the cyclic regime. Fertilizer source influenced cumulative amounts (mg/year) of ammonium-N, nitrate-N and orthophosphate in the container leachate. Nitrate-N and ammonium-N from Harrell's 17N–2.2P–10.0K fertilizer were each ≈20% higher in the container leachate from sweetbay magnolia than Osmocote 19N-2.2P-7.5K fertilizer. In the case of the willow oak, the differences were 32% and 19%, respectively. Orthophosphate averaged about 65% greater in leachate from both sweetbay magnolia and willow oak containers when grown with Osmocote compared to Harrell's fertilizer. At the end of year two, height and caliper growth were similar among treatments with both species.