Search Results

You are looking at 161 - 170 of 649 items for :

Clear All

Single-pinched poinsettias (Euphorbia pulcherrima Willd. ex Klotzsch `V-14 Glory') received 210 mg·L-1 constant N fertigation from Hoagland solution with N sources of 100% NO3-N or 60% NO3-N : 40% NH4-N, P concentrations of 7.8 or 23 mg·L-1, and leaching fractions (LFs) of 0, 0.2, or 0.4. The P fertigation rates did not significantly affect plant growth measurements and N leaching. Shoot dry masses and leaf and bract areas of plants fertigated with 60% NO3-N were 11% to 26% greater than those fertigated with 100% NO3-N. Shoot dry mass at the 0 LF was 27% smaller than those at the 0.4 LF. The total amount of N applied via fertigation was 1.7 g at the 0 LF and 3.3 g at the 0.4 LF. Leachate N concentration ranged from 170 to 850 mg·L-1. Nitrogen recovery was 74% to 91%, and the percentage of fertigation N recovered in leachate ranged from 51% at the 0.2 LF to 74% at the 0.4 LF. With a 0.4 LF and 210 mg·L-1 N fertigation, 15% to 22% of the recovered N was found in the shoots, and 68% to 75% was found in the leachate. Even with a 0.2 LF, >50% of the N recovered was found in the leachate. Premium marketable quality poinsettia were produced with N at 210 mg·L-1 from 60% NO3-N : 40% NH4-N fertigation solution at the 0.4 LF. To reduce N leaching to the environment, good marketable quality poinsettias could be grown at a LF of ≤0.2 with 210 mg·L-1 N fertigation if quality irrigation water is available and if a small reduction in growth is acceptable.

Free access

Abstract

Celery (Apium graveolens L.) seeds germinated at 10°C for 14 days produced shorter and more uniform radicles (0– mm) than seeds germinated for 8 days at 24° (0–10 mm). Removal of seed leachates improved the germination of celery seeds in the light. Celery seeds germinated at 10° prior to sowing emerged faster, and produced more uniform plants than those not pregermihated, and were not thermodormant when incubated at 32°.

Open Access

Municipal solid waste compost (MSW) can be used as an effective substrate for ornamental plant production as an alternative to peat. In a previous study a mix with peat, perlite, and vermiculite (1:1:1 per volume) was used along MSW compost at 1:1 per volume ratio as a growing substrate for Catharanthus roseus, providing nitrogen (N) for adequate plant growth. This study will focus in determining if MSW provides adequate amounts of N and Phosphorous (P) for Anthurium pot plant production, reducing the use of fertilizers and nutrient loss to the environment. Plants were fertilized at 0, 100, 150, and 200 ppm N using a 20-10-20 soluble fertilizer. Chemical characterization of leachates collected from plants grown in substrates with or without MSW, to determine possible nutrient run off. Tissue analysis for N and P content was conducted to determine absorption. Our results shows an increase in NH4 -N, NO3 -N and soluble P in leachates as the fertilizer level increased. Higher NO3 -N content in leachates was observed in treatments with MSW. Higher P concentrations were observed in leachates from substrate without MSW. Weeks after, 62% of the plants grown in MSW were dead; the surviving plants had less biomass, but similar N content in leaf and root tissues than plants grown without MSW. Higher P content in tissues was observed in fertilized plants grown without MSW. The MSW was a nutrient source for the plants, but further studies should be conducted for optimum use of MSW as a component of growing substrate.

Free access
Author:

Abstract

Viterra hydrogel at rates of 0, 1.75, or 2.50 kg·m−3 was tested for the production of three tropical ornamental plant species in two or all of the three media. These were a commercial peat-lite medium (SUN), a medium consisting of equal volumes of peatmoss, bark, and sand (PBS), and a mix containing equal volumes of peatmoss and bark (PB). Codiaeum was grown in SUN and PBS, Dieffenbachia was produced in all three media, and Hibiscus was planted in SUN and PB. Codiaeum variegatum (L.) Blume ‘Norma’ and Dieffenbachia ‘Camille’ grew more and required a longer time to reach initial wilting when grown in SUN than PBS. Hibiscus rosa-sinensis L. ‘Brilliant Red’ had similar growth in SUN and PB. In general, hydrogel had no beneficial effect on plant growth in a greenhouse. Hydrogel extended the time required to reach initial wilting of C. variegatum by 3 days (from 24 to 27 days), but had no effect on Dieffenbachia. Leachate from PBS had higher pH and lower electrical conductance (EC) than that from SUN. Hydrogel had no effect on leachate pH, but decreased EC of the leachate for C. variegatum used at the 2.5 kg·m−3 rate and for H. rosa-sinensis at both rates.

Open Access

These studies were conducted to determine the effect of 1) temperature on P leaching from a soilless medium amended with various P fertilizers, 2) water application volume on P leaching, and 3) various fertilizers on P leaching during production and growth of marigolds (Tagetes erecta L. `Hero Flame'). Increasing temperature linearly decreased leaching fraction; however, total P leached from the single (SSP) or triple (TSP) superphosphate-amended medium did not differ regardless of temperature. Despite a smaller leaching fraction at higher temperatures and no change in the total P leached, P was probably leached more readily at higher temperatures. More P was leached from the medium amended with uncoated monoammonium phosphate (UCP) than from the medium containing polymer-coated monoammonium phosphate (CTP) at all temperatures, and more P was leached from UCP-amended medium at lower temperatures than at higher temperatures. More P was leached from TSP- than from SSP-amended medium and from UCP- than from CTP-amended medium regardless of the water volume applied, but leachate P content increased linearly as water application volume increased for all fertilizers tested. Plant dry weights did not differ regardless of P source. Leachate electrical conductivity (EC) was lower with TSP than with SSP. Leachate EC was also lower with CTP than with UCP. A higher percentage of P from controlled release fertilizer was taken up by plants rather than being leached from the medium compared to P from uncoated fertilizers.

Free access

Phosphorus contamination of surface water is a growing problem associated with container production of nursery plants. Iron and iron compounds have the ability to adsorb phosphorus and render it immobile. Incorporating iron compounds into media at the base of nursery containers serves to filter out phosphorus from fertilizers while still allowing the plant to collect enough phosphorus to grow. Two experiments were devised. The first experiment examined how much phosphorus various iron compounds would adsorb. Metallic iron adsorbed the most phosphorus, followed by HCl reacted magnetite (a form of iron ore), Fe2O3, Fe3O4 and magnetite. In the second experiment, PVC tubes (4 cm inner diam.) were filled to a level of 5 cm with a phosphorus adsorbing layer containing growing media that was 25% or 50% by weight iron compounds. Compounds included metallic iron, HCl reacted magnetite and magnetite. Plain media was used as a control. A layer of 15 cm of media and slow-release fertilizer was applied above the adsorptive layer. One hundred milliliters of distilled water was applied to PVC tubes daily to simulate irrigation. Metallic iron reduced phosphorus leachate to almost 0 for over 2 weeks. HCl reacted magnetite was also effective in reducing phosphorus leachate. Magnetite only affected phosphorus leachate slightly.

Free access
Author:

A study was conducted with Prunus × incamp `Okame' to evaluate the effects of a pot-in-pot production system compared to a conventional above-ground system and cyclic irrigation on plant growth and water loss. Plants were grown in #7 (26-L) containers with a 8:1 pinebark:sand (v/v) substrate. Cyclic irrigation provided the same total volume of water, but was applied one, three, or four times per day. Final plant height and stem diameter, shoot and root dry weight, total biomass, and root:shoot ratio were all increased for plants grown pot-in-pot compared to above-ground. Multiple irrigation cycles increased stem diameter, shoot dry weight, and total biomass, compared to a single irrigation application. Multiple irrigation cycles decreased the root:shoot ratio. Evapotranspiration was influenced by production system, irrigation, and date. Amount of water lost as leachate was influenced by irrigation and date. Cyclic irrigation resulted in a two-fold decrease in leachate volume. Soluble salts and nitrate-nitrogen in the leachate were influenced by an interaction between production system, irrigation, and date.

Free access

Abstract

Ground limestone (CaCO3) was applied at 0, 25, 50, 75, or 100 g/9.5-liter pot using a 1 peat : 1 perlite : 1 vermiculite (by volume) medium having an initial pH of 4.52 and an electrical conductivity (EC) of 0.2 dS·m–1. Muskmelon (Cucumis melo var. reticulatus) were grown for 56 days in the medium that had been fertilized. Irrigations were applied as the crop grew, with the levels used consisting of 0%, 20%, 40%, or 60% in excess of the amount required to bring all pots to saturation. The water had a pH of 7.44 to 7.95 and an EC from 1.5 to 1.8 dS·m–1. Measurements were taken at each irrigation. Leachate pH increased with increasing rate of limestone application, but the rate of increase with increasing limestone rate declined, with maximum benefit occurring at 75 g/pot. Irrigtation level did not affect leachate pH, which indicates a buffering capacity of the medium that was not readily diluted. Increasing limestone application decreased leachate EC, which suggests retention of the salts from the irrigation water. This retention resulted in a net accumulation of salts in the medium that could not be completely offset by the increased leaching produced as irrigation levels increased.

Open Access

A study was conducted to test the ability of hydrophilic polymers to retain moisture in annual bedding plant beds in addition to reducing NO3 and NH4 leaching. Petunia plants were transplanted into raised concrete benches containing a drainage pipe that allowed for excess leachate to be collected. Beds that were treated with 0 or 366 g·m–2 of hydrogel and 0 or 186 g of ai N. Watering of beds followed a strict irrigation schedule and soil moisture was monitored daily. At termination, plant dry weight was measured and analyses of plant tissue and leachate were conducted for NO3 and NH4 concentrations. Results from this study demonstrated that, under suboptimal conditions of minimal irrigation and fertilization, polymer incorporation had a significant effect on water, NH4, and NO3 retention in soils. Water leaching was decreased by 17%; NH4 retention was increased by 83%; and NO3 retention, where additional N was added, was increased by 64% due to polymer incorporation. In addition, a 47% reduction in NO3 concentration of water leachate was detected when polymer was incorporated under minimal fertilization. Growth or N levels of petunia were not significantly affected by polymer incorporation.

Free access

Easter lilies, Lilium longiflorum Thumb. cv Nellie White, were grown in a commercial pine bark-based medium (25% by vol.), amended with 0.5 g Acrylamide Acrylate Gel (AAG) per 1.6 liter pot. Lilies were grown in media drenched with ancymidol, at 0, 0.25, 0.375 or 0.5mg a.i.pot-1 following shoot emergence, or grown in media containing ancymidol impregnated AAG at 0, 0.25, 0.375 or 0.5mg a.i.pot-1. AAG applied ancymidol treatments resulted in a significant linear decrease in both lily stem and internode length as the rate of ancymidol increased. Drench applied ancymidol had no affect on stem or internode length. Stem and internode lengths of drench treated lilies were not significantly shorter than lilies not exposed to ancymidol. Bud length, leaf and bud number, and days to anthesis were not affected (P≤0.05) by any treatment. Ancymidol activity in the top, middle and bottom strata of medium filled containers, and in the leachate from these containers, was measured using a lettuce hypocotyl length bioassay. Ancymidol activity was uniformly distributed throughout the bark medium when applied in AAG. With this treatment, 10-15% of the ancymidol activity was detected in the leachate. When ancymidol was applied as a drench, over 95% of the activity was detected in the top two strata, with 70% in the upper most stratum and the rest in the leachate.

Free access