Media fertility, nutrient availability, and subsequently plant nutrition are critical factors that can be modified by growers to produce quality container-grown plants. The trend in container fertility has been toward incorporation of slow-release fertilizers; however, fertility release curves are variable and fertilizer longevity for many fertilizers is limited. Seventeen slow-release fertilizers were compared for longevity and plant performance over a 2-year production cycle using deciduous and evergreen plant materials. Plant growth was quantified based on height, volume, branching, dry weight, and quality. Soil fertility levels based on leachates were followed. Nutrient release for the incorporated fertilizers evaluated was variable. Fertility treatment effects were species-dependent. Several incorporated, slow-release fertilizers, especially those high in nitrogen and having extended release curves, including Nutricote 20–7–10, Scotts Experimental 24–6–10 and 26–6–11, Scotts Prokote Plus 20–3–10, Sierra 17–6–10, Sierra High N 24–4–6, Sierra Experimental 24–4–8, Woodace 21–4–10, Woodace 23–7–12, and Woodace Briquettes 23–2–0, show promise for use in 2-year container production systems.
James B. Calkins and Bert T. Swanson
Jason D. Murray, John D. Lea-Cox, and David Ross
The physical properties of soilless substrates used in the nursery industry vary widely throughout the US, and, as such, present problems for accurate irrigation water management. Water management in soilless substrates is also a key factor in reducing the loss of soluble nitrogen and phosphorus from the root volume. Automated irrigation control that maintains the substrate water content above levels of plant water stress, yet below the maximum water holding capacity of the substrate will serve several positive roles: water and nutrients will be conserved, and losses from run-off minimized. We investigated whether Time Domain Reflectrometry (TDR) moisture sensors can be effectively calibrated for a range of horticultural substrates in various container sizes. A series of water desorption curves and TDR wave-traces (n = 10) were simultaneously derived for six soilless substrate source materials (pine bark, hardwood bark, promix, perlite, rockwool and a sieved sand control), using a modified tension table with four column heights (7-, 15-, 20-, and 25-cm equating to rockwool, #1, #3, and #5 pot sizes). Modifying the tension table allowed for the replication of individual columns (n = 10) of each substrate. The volumetric water desorbed at increasing desorption (positive air) pressures from 0 through 100 KPa was collected for each treatment. Repeated measurements with this apparatus allowed us to plot standard TDR curves for each substrate that can be used to accurately schedule cyclic irrigations. Implementing automated cyclic irrigation strategies in container production will allow for better monitoring and control of irrigation applications, and help conserve water and nutrients in the nursery.
Peter J. Zale, Daniel K. Struve, Pablo Jourdan, and David M. Francis
morphological and flowering characteristics and to assess whether a container production system could be used to accelerate genetic testing ( Struve and McKeand, 1993 ). The objective was to determine the degree of genetic control over these traits when plants
Alyssa J. DeVincentis, Robin G. Brumfield, Paul Gottlieb, and James R. Johnson
changing their production schedules and the value of their crops ( Majsztrik et al., 2011 ). One way to manage water runoff in container production is to convey rain and irrigation runoff to a containment pond for reuse ( Yeager, 2008 ). Recycling
Taryn L. Bauerle, William L. Bauerle, Marc Goebel, and David M. Barnard
variability. Intensive ornamental tree container production systems stand to benefit from optimal water and fertilizer inputs. Substrate moisture sensors offer a plausible and affordable method to monitor and control irrigation. As a means to effectively
Hala G. Zahreddine, Daniel K. Struve, and Salma N. Talhouk
research papers discuss recommended nitrogen (N) fertilizer rates for woody ornamentals grown in container production systems in the United States ( Gilliam et al., 1980 , 1984 ; Ingestad, 1979 ; Jull et al., 1994 ; Larimer and Struve, 2002 ; Lumis et
Neil O. Anderson and Esther Gesick
The prostrate plant habit may be an important new trait for the garden chrysanthemum [Dendranthema ×grandiflora Tzvelv. (=Chrysanthemum ×morifolium Ramatuelle)] market. Fifteen prostrate and non-prostrate genotypes were evaluated in production trials, using Regular and Fast Cropping systems. At flowering, the following traits were evaluated: days to flowering (first, 50%, 100%), flowering duration, pot coverage, plant uniformity, and salability. Salability was measured with consumer evaluations. Genotypes differed significantly for days to first and 100% flowering, flowering duration, plant height, plant width, and plant uniformity. Cropping systems were significantly different for days to first and 100% flowering. `Snowscape', a semi-prostrate day-neutral cultivar, was earlier than all other genotypes for days to first flower. It also had the longest flowering duration. `Snowscape' would be the best genetic source for creating early, continual flowering cultivars. Most prostrate genotypes were as early as commercial cultivars. Genotype 90-275-27 was significantly shorter (prostrate) than all other genotypes and would be the best genetic source for prostrate plants. Genotypes 95-169-8, 92-237-9, 95-157-6, 95-169-10, 90-275-27, and `Snowscape' had the most acceptable plant width for shipping. Plant uniformity of 95-169-10 and 95-169-8 matched that of `Debonair' and `Spotlight', all of which were significantly more uniform than the other genotypes. The least uniform prostrate was 95-331-10. `Snowscape' had the highest (best) index of traits ranking and was significantly better than all other genotypes. Consumer evaluations were highest for non-prostrate cultivars.
L.T. Case, H.M. Mathers, and A.F. Senesac
Container production has increased rapidly in many parts of the U.S. over the past 15 years. Container production has been the fastest growing sector in the nursery industry and the growth is expected to continue. Weed growth in container-grown nursery stock is a particularly serious problem, because the nutrients, air, and water available are limited to the volume of the container. The extent of damage caused by weeds is often underestimated and effective control is essential. Various researchers have found that as little as one weed in a small (1 gal) pot affects the growth of a crop. However, even if weeds did not reduce growth, a container plant with weeds is a less marketable product than a weed-free product. Managing weeds in a container nursery involves eliminating weeds and preventing their spread in the nursery, and this usually requires chemical controls. However, chemical controls should never be the only management tools implemented. Maximizing cultural and mechanical controls through proper sanitation and hand weeding are two important means to prevent the spread and regeneration of troublesome weeds. Cultural controls include mulching, irrigation methods (subirrigation), and mix type. Nursery growers estimate that they spend $500 to $4000/acre of containers for manual removal of weeds, depending on weed species being removed. Economic losses due to weed infestations have been estimated at approximately $7000/acre. Reduction of this expense with improved weed control methodologies and understanding weed control would have a significant impact on the industry. Problems associated with herbicide use in container production include proper calibration, herbicide runoff concerns from plastic or gravel (especially when chemicals fall between containers) and the need for multiple applications. As with other crops, off-site movement of pesticides through herbicide leaching, runoff, spray drift, and non-uniformity of application are concerns facing nursery growers. This article reviews some current weed control methods, problems associated with these methods, and possible strategies that could be useful for container nursery growers.
Mark H. Brand
The effect of shading during nursery production on the growth, foliage color, and foliar chlorophyll content of container-grown Kalmia latifolia cultivars was investigated. Five cultivars were grown under 40% shade, 60% shade, or full sunlight for a 2-year production cycle. During the first year of production, there were no significant differences in measured growth characteristics for most cultivars in response to light treatment. Shade improved foliar color by decreasing lightness (L*), decreasing chroma, and changing hue angle from a yellow-green to a darker green. Foliar chlorophyll concentration increased under shade. In the second year of the production cycle, the response of foliar color and chlorophyll concentration to shade was similar to that observed in year 1. Plant size, number of branches, leaf area, leaf dry mass, and stem dry mass decreased linearly with increasing shade in year 2. Although shading improves foliar color, it probably should not be employed for container production of Kalmia latifolia in cool, northern production areas due to reduced plant growth during year 2. Shade may be useful in the first year of production to enhance foliar color without reducing shoot growth.
R.C. Beeson Jr. and G.W. Knox
Volume of water captured in a container as a function of sprinkler type, spacing, plant type, and container size was measured for marketable-sized plants. Percent water captured was calculated and a model to predict this value derived. Percent water captured was inversely related to the leaf area contained in the cylinder over the container when containers were separated, and with total plant leaf area at a pot-to-pot spacing. This relationship was independent of leaf curvature (concave vs. convex). Canopy densities were less related to percent water captured than leaf areas. Irrigation application efficiencies separated by spacing ranged from 37% at a close spacing to 25% at a spacing of 7.6 cm between containers. Container spacing, canopy shedding, and possibly some canopy retention of water later lost by evaporation were determined to be the main factors associated with the low efficiencies. The results suggest that higher irrigation application efficiencies would be maintained only if plants were transplanted to larger containers before reaching maximum canopy size rather than spacing existing containers to achieve more room for canopy growth.