Nursery Pots Research Articles

Development and validation of hydrophobic molded pulp nursery pots made of hemp hurd

Biodegradable nursery pots (BNPs) composed of 50 % hemp hurd and 50 % recycled cardboard fibers (w/w dry basis) were produced using a custom-built handheld molded pulp device. Milling followed by sequential peracetic acid and sodium hydroxide delignification treatment reduced lignin content of hemp hurd from 23.76 % to 2.39 %, liberating cellulose and hemicellulose fibers for enabling the formation of interfiber interactions in molded pulp formulations. Beeswax and precipitated calcium carbonate based hydrophobic coating at ~10 μm thickness significantly enhanced hydrophobicity of the BNPs, as indicated by the surface contact and sliding angle of 116.25° and 34.82°, respectively. Anaerobic biodegradability of BNP was confirmed via carbon dioxide and methane gas accumulation measurements. Developed BNPs were successfully validated through an eleven week greenhouse planting trial. This study introduced a new biodegradable molded pulp formulation made from hemp hurd and validated its application as an alternative to single use plastic nursery pots for growing seedlings.

Evaluation of Quality Performance in Paper Pulp vs. Polyethylene Nursery Pots for Green Sustainability

The use of biodegradable paper pulp pots has been gaining traction, especially among environmentally conscious consumers and horticultural practitioners who prioritize sustainability. The choice between paper pulp and polyethylene nursery pots in horticultural practices is a complex decision, involving considerations such as environmental impact, cost-effectiveness, durability, and overall sustainability. This study aims to provide practical insights into the comparative performance of paper pulp and polyethylene pots, specifically in terms of plant health, degradation, and techno-economic considerations. The study involved the growth performance assessment of four plant species, Cannonball Tomato, Celebrity Tomato, Parris Island Lettuce, and French Marigold, in a greenhouse experiment setup. Additionally, a degradation analysis was conducted to determine the average degradation rate and pattern. Finally, a techno-economic analysis compared the value of plant health and degradation with the market price. By evaluating the quality performance aspects of paper pulp pots, this study not only provides valuable insights but also identifies potential areas of improvement for other biodegradable pots, thereby contributing to the ongoing efforts to promote sustainable horticultural practices.

Sustainable seedling pots: Development and characterisation of banana waste and natural fibre-reinforced composites for horticultural applications

Plastic pots used in horticultural nurseries generate substantial waste, causing environmental pollution. This study aimed to develop biodegradable composites from banana pseudo-stem reinforced with agricultural residues like pineapple leaves, taro and water hyacinth as eco-friendly substitutes. The aim of this study is to develop optimised banana biocomposite formulations with suitable reinforcements that balance mechanical durability, biodegradation, and seedling growth promotion properties to serve as viable eco-friendly alternatives to plastic seedling pots. This study was carried out by fabricating banana fibre mats through pulping, drying and hot pressing. Composite sheets were reinforced with 50 % pineapple, taro or water hyacinth fibres. The mechanical properties (tensile, yield strength, elongation, bursting strength), hydrophilicity (contact angle, water absorption), biodegradability (soil burial test), and seedling growth promotion were evaluated through appropriate testing methods. The results show that banana-taro composites exhibited suitable tensile strength (25 MPa), elongation (27 %), water uptake (41 %) and 82 % biodegradation in 60 days. It was observed that biodegradable seedling trays fabricated from banana-taro composite showed 95 % tomato seed germination and a 125 cm plant height increase in 30 days, superior to plastic trays. The finding shows that the study demonstrates the potential of banana-taro biocomposites as alternatives to plastic nursery pots, enabling healthy seedling growth while eliminating plastic waste pollution through biodegradation.

Co-Composting of Green Waste and Dredged Sediments Can Reduce the Environmental Impact of the Potted Nursery without Affecting Plant Growth

The ornamental nursery industry is steadily growing in Europe, and a consequent increase in the demand for substrates related to container plant cultivations is expected in the coming years. Currently, substrates consist in part or entirely of peat, a non-renewable resource with concerns about its environmental impact due to extraction, transport, and use. Therefore, it is essential to focus on alternative materials, particularly waste by-products to be recycled as components of substrates to achieve more sustainable cultivations. In this study, substrates obtained by mixing co-composted dredged sediments (S) and green waste (GW) in different ratios (1:3; 1:1; 3:1) were tested for cultivation, and plant growth was compared with a control growing media (peat and pumice in a 1:1 ratio). The cultivation trial lasted for one year and was carried out on two potted ornamental evergreen shrubs (Photinia × fraseri and Viburnum tinus). The results showed that the plant growth parameters of both species, occurring in substrates with co-composted materials, were not significantly affected compared to the control, with the exception of below-ground biomass in V. tinus. Moreover, a Life Cycle Assessment (LCA) analysis was carried out to quantify the greenhouse gas emissions (GHG) deriving from the replacement of peat with the other proposed substrates. The functional unit was 10 L (Ø 24 cm) potted plants and the results were expressed in kg of CO2 equivalent (kg CO2eq). We demonstrated that the replacement of peat-based substrates with the alternative substrates was able to reduce the GHG emission by an average of 11.56 to 23.13%. Higher GHG emissions were related to the cultivation phase (0.9 kg CO2eq/plant), and while comparing substrates, we obtained an average percentage reduction of 28.1% to 59.6%. Thus, our results suggest that co-composted mixtures of dredged sediments with green waste could be used as sustainable techno-soils for pot nursery cultivation of ornamental species with reduced environmental impact.

대목별 DMSO (Dimethyl sulfoxide) 및 IBA (Indole-3 butyric acid) 처리농도가 포도 ‘흑보석’ 포트묘 생산에 미치는 영향

대목별 DMSO (Dimethyl sulfoxide) 및 IBA (Indole-3 butyric acid) 처리농도가 포도 ‘흑보석’ 포트묘 생산에 미치는 영향

Evaluation of alternative nursery potting mixtures for betel (<em>Piper betle</em> L.)

Betel (Piper betle L.) is a woody climber with cultural and economic significance. Precise potting mixture is a prerequisite to produce quality nursery plants. Exploring alternative potting mixtures is crucial in addressing limitations associated with traditional potting mixtures. This research aimed to evaluate the different alternative potting mixtures for nursery production of betel. The research was conducted at Betel Research Station, Department of Export Agriculture, at Narammala. Seven potting mixtures were prepared using different ratios of topsoil, coir dust, sand, cattle manure, compost, goat manure, Partially Burnt Paddy Husk (PBPH) and poultry manure. Department of Export Agriculture (DEA) recommended potting mixture (Topsoil: Sand: Coir dust: Cattle manure 1:1:1:1) was used as the control (T1). This experiment was laid out in a Complete Randomized Design and each treatment consisted 15 nursery pots. “Ratadalu” stem cuttings were used as planting materials. Analysis was done on the EC, pH, and N, P, and K content of the nutrients in potting mixes. Growth parameters; number of leaves, shoot length and diameter were recorded weekly. Survival rate, shoot and root weight, root volume measured at 9th week. Except, T8 (Topsoil: PBPH: Poultry manure 1:3:1) potting mixture, other alternative nursery potting mixtures showed similar performances to control (T1) for most of the tested parameters. Out of alternative mixtures, T2 potting mixture exhibited more similar performances to the DEA recommended potting mixture. Therefore, T2 (Topsoil: Sand: Coir dust: Compost 1:1:1:1) can be suggested as the best alternative potting mixture for nursery production of betel.

Recycled Waste Leaf Litter Pots Exhibit Excellent Biodegradability: An Experimental Analysis

The growth of the gardening kit market could result in the increased wasting of nursery pots, which are usually made of plastic. Replacing these pots with biodegradable pots made from green waste could have benefits for climate mitigation, the circular economy, and the greenness of gardening. To address this, we introduce a prototype recycled waste leaf litter (RWLL) nursery pot. Via an incubation experiment over 90 d, we examined their biodegradability and effects on microbial enzyme activity and inorganic nitrogen concentration, comparing them with commercially available biodegradable pots, namely peat–paper mixture pots (also known as Jiffypots®) and coco-coir pots. The effects of pot thickness were tested. Based on mass loss during incubation and on soil CO2 efflux, the RWLL pots exhibited excellent biodegradability, regardless of their thickness, with decomposition rates and soil CO2 efflux 1.5–6 times greater than other biodegradable pots. Biodegradability, extracellular enzyme activity, and soil inorganic nitrogen content were not affected by RWLL pot thickness or by the presence or absence of a plant in the soil. Unlike in natural ecosystems, leaf litter is treated as waste in urban green spaces, and its decomposition into soil organic matter is prevented. Creating plant pots from leaf litter enhances soil quality, reduces atmospheric carbon emissions, and satisfies the desire of gardeners for greenness.

Effect of Degumming Duration on the Behavior of Waste Filature Silk-Reinforced Wheat Gluten Composite for Sustainable Applications.

Silkworm silk proteins are of great importance in several fields of science owing to their outstanding properties. India generates waste silk fibers, also known as waste filature silk, in abundance. Utilizing waste filature silk as reinforcement in biopolymers enhances its physiochemical properties. However, the hydrophilic sericin layer on the surface of the fibers makes it very difficult to have proper fiber-matrix adhesion. Thus, degumming the fiber surface allows better control of the fiber properties. The present study uses filature silk (Bombyx mori) as fiber reinforcement to prepare wheat gluten-based natural composites for low-strength green applications. The fibers were degummed in sodium hydroxide (NaOH) solution from a 0 to 12 h duration, and composites were prepared from them. The analysis exhibited optimized fiber treatment duration and its effect on the composite properties. The traces of the sericin layer were found before 6 h of fiber treatment, which interrupted homogeneous fiber-matrix adhesion in the composite. The X-ray diffraction study showed enhanced crystallinity of the degummed fibers. The FTIR study of the prepared composites with degummed fibers showed that shifted peaks toward lower wavenumbers supported better bonding among the constituents. Similarly, the tensile and impact strength of the composite made of 6 h of degummed fibers showed better mechanical properties than others. The same can be validated with the SEM analysis and TGA as well. This study also showed that prolonged exposure to alkali solution reduces the fiber properties, thus reducing composite properties too. As a green alternative, the prepared composite sheets can potentially be applied in manufacturing seedling trays and one-time nursery pots.

IMPACT OF MACRONUTRIENTS ON THE PRODUCTION OF CLEAN AND HEALTHY MANGO NURSERY PLANTS IN POLYBAGS UNDER NURSERY TUNNEL

Mango nursery production under polybags is highly depend on application of various fertilizers for developing healthy and vigorous nursery plants. Mango nursery was grown in polybags placed undera nursery tunnel. The fertilizer (N:P:K 20:20:20) were applied as control or no application, 5g, 10g, 15g and 20g into the polybags after 30 days of seedling transplanting into poly pots followed by irrigation of 500ml water into the pots. The data was recorded after 30, 60 and 90 days intervals in terms of plant height, root length, number of leaves per plant, and number of vegetative flushes per plant after applying nutrition to the plants. The results revealed that the maximum plant height of 67.21cm was observed when pots were fertilized @ 10g per pot followed by irrigation of 500ml water. In comparison,the root length was 22cm, number of leaves per plant was 31.33, and the number of vegetative flushes 8 per plantwasobserved when mango nursery pots were fertilized with 10g per pot.

Comprehensive analysis of the mechanism underlying plastic microbiome and plants interaction, with future perspectives

Agriculture has a vital role in the life cycle of an economy. Phytopathogenic microorganisms negatively influence many crops, the economy, and the Environment worldwide. Beneficial plant microbiomes have the immense potential to provide cost-effective and maintainable solutions to existing agricultural challenges. The yield improvement can partly be credited to advanced plant pest and disease management, including better knowledge of phytopathogens and diverse control methods. Well-organized and balanced crop protection is of vast economic and ecological importance for food and feed production. A varied variety of goods made of plastics are utilized in farming which consists of poly-tunnels, plastic reservoirs, mulches, ropes, agrochemical cans, various nets, irrigation systems, packaging bags, nursery pots, anti-bird nets, greenhouses, and their components, wear and tear of these products are hosts of diverse microorganisms in agriculture. However, little investigation has been done to explore plastic microbes' diversity, survival strategies, and interaction mechanisms with plants. Several advanced approaches, including metagenomics, metabolomics, metatranscriptomics, metaproteomics, and culturomics, are currently available to scrutinize the multiplicity, composition, and functions of the microbiomes in soil and plant habitats such as rhizosphere, phyllosphere, and endosphere. This review highlights the increasing use of plastic, plastic microbiomes, subsequent challenges, and future perspectives in agriculture. It emphasizes using advanced molecular tools and techniques to explore the microbiome diversity and the mechanism of plant-microbe interaction. The analyzed knowledge gaps in the host-pathogen relationship research area will help to redraft better research approaches based on economic thresholds.

Food Waste-Derived Biomaterials Enriched by Biostimulant Agents for Sustainable Horticultural Practices: A Possible Circular Solution

The horticultural industry claims the substitution of plastic plantlet containers, which derive from oil-based raw materials and cannot be recycled, with bio-based ones, aiming to decrease waste management costs and increase the overall production sustainability. Bio-based fully biodegradable nursery pots can be directly placed in soil, thus decreasing the plantlet transplant stress and labor, and avoiding waste generation. The development of biomaterials specifically obtained from food-derived wastes like fruit and vegetables will add further advantages by an improved use of resources, the production of added-value materials and the replenishment of food losses, in a perfect circular economy approach. A multidisciplinary strategy combining material science, microbiology, agronomy and economy will, moreover, allow the development of functionalized food-waste derived materials, enriched in biostimulant extracts, alive plant-growth promoting microorganisms and thermal buffering molecules, obtaining biodegradable and biofertilising plant multiplication plugs with the potential to increase the sustainability of the overall agri-food production chain.

EFFECTS OF Gliricidia sepium RESIDUE VERMICOMPOST ON THE YIELD AND DRY MATTER BIOMASS OF ORGANIC CHOY SUM MUSTARD

As the population grows and resource consumption increases, waste management has become a significant environmental challenge. A more sustainable approach to waste management is essential to maximize the recovery of materials acquired from nature. Vermicomposting is one of the answers to sustainable waste management. A study was conducted to determine the viability of vermicomposting Gliricidia sepium leaves and office scrap paper with matured compost as feedstock and to determine the vermicompost characteristics and suitability as potting mixtures for vegetable cultivation. The choy sum mustard was selected as the test crop. The plants were grown in the pots in a netted nursery in Serdang, Selangor. Treatments were mixtures of vermicompost to soil ratio by volume: control (0% no vermicompost), T1 (20% vermicompost), T2 (40% vermicompost), T3 (60% vermicompost), T4 (80% vermicompost) and T5 (100% vermicompost). Physicochemical properties of the potting media mix were determined and compared to an established growth media concentration and other ASEAN standards. Crop growth was evaluated by measuring plant height, the number of petioles, and fresh and dry weights at harvest. A significant improvement in the physicochemical properties of the media was observed, where the optimum ratio of potting media was 60% to 80% (T3 & T4). The number of petioles was 20-46% higher, plants were 39-46% taller, and dry matter accumulation was three-fold higher than controls. Crop yields were 200% higher in media treatments consisting of 60-80% vermicompost. In conclusion, G. sepium based vermicompost could be used in media mixtures for potting plants.

Humic substances stimulate initial growth and reduce arsenic stress in Corymbia citriodora seedlings

The use of arsenic (As) tolerant plants and those with a well-developed root system have shown great relevance in phytoremediation campaigns. Corymbia citriodora presents these characteristics that can be enhanced by humic substances (HS) from organic matter. The objective of the present study was to determine if HS extracted from vermicompost can modify the root system architecture, stimulate growth, increase robustness and relieve stress promoted by As in C. citriodora seedlings. Two preliminary tests were carried out to obtain the best concentration-response for HS and the toxic As concentration. Subsequently, an experiment was carried out in nursery pots with nutrient solution and four treatments: Control, HS, As and As + HS. HS alleviated the reduced growth caused by As with regards to dry mass, root collar diameter and height of the aerial part. The Dickson quality index (DQI) was reduced by the action of As and this negative affect was mitigated by HS. Our results show the positive effect of the HS in alleviating As abiotic stress in C. citriodora seedlings, demonstrating its potential to mitigate the toxicity of this chemical element.

Supplemental Nickel Corrects Mouse Ear Disorder of Bitternut Hickory

Abstract While sought after for use in managed landscapes, bitternut hickory [Carya cordiformis (Wang.) K. Koch] remains underutilized in horticulture due its reputation for difficulty with production and transplanting. After learning of issues experienced by growers and observing deformed leaf development of container-grown stock, we examined effects of supplemental nickel applications on seedlings of bitternut hickory. We hypothesized that, like the closely related species pecan [Carya illinoinensis (Wang.) K. Koch], bitternut hickory would be similarly limited in production by a susceptibility to mouse ear disorder as a function of nickel deficiency. Seedlings cultivated with a soilless substrate in 3.8L (#1) nursery pots were treated with either a substrate drench or foliar spray of Nickel Plus® two weeks after budbreak. After 30 days, plants treated with a drench or foliar spray exhibited increased leaf area and decreased number of leaves per unit shoot extension and leaf greenness compared to nontreated controls. Foliar treatments resulted in an 83.5% increase in shoot extension over nontreated controls. Whereas seedlings provided supplemental nickel displayed healthy foliage after treatment, nontreated seedlings exhibited traditional symptoms of mouse ear disorder. These data indicate bitternut hickory is susceptible to mouse ear disorder, an issue remedied by supplementing nickel. Index words: foliar spray, substrate drench, soilless substrate, nursery production, ornamental plants. Chemicals used in this study: nickel lignosulfonate (Nickel Plus®). Species used in this study: bitternut hickory, Carya cordiformis (Wang.) K. Koch

Influence of urea fertilizer on early growth of African Rose Wood (Pterocarpus erinaceous Poir.) seedlings in Kaduna State, Northern Nigeria

Influence of urea fertilizer on early growth and development of Pterocarpus erinaceous seedlings were investigated. Two hundred (200) uniformly growing seedlings were transplanted into polythene pots filled with top soil. Four urea fertilizer rates (0.035; 0.065; 0.095; 0.0125 g) and control were applied to the seedlings in the pots 20 × 25 × 25 cm, filled with 800 g of top soil collected from forest plantation. Assessment on the metrical character of the seedlings was done fortnightly. The fertilization of the selected seedlings with urea fertilizer was done round the seedlings in the nursery pots using ring method. The experiment was laid out in a completely randomized design. The data were subjected to analysis of variance, and means were separated using Duncan’s multiple range test at p < 0.05. The results show that fertilizer rates had significant (p < 0.05) effect on the growth and development of seedlings of P. erinaceous. Seedlings treated with 0.095 g of urea produced the highest mean values of 12.00 ± 0.66 cm; 0.33 ± 0.01 mm; 190 cm2 and 12.65 ± 0.67 for stem height, collar diameter, leaf area (LA) and number of leaves respectively. Seedlings fed with 0.125 g had the lowest values of 11.19 ± 0.61cm for height, 0.32± 0.01 mm for collar diameter 11.54 ± 0.70 for number of leaves and 124 cm2 for the LA. Urea fertilizers had significant effect on the early growth of the seedlings, therefore fertilization at 0.095 g per pot is recommended for raising P. erinaceous seedlings.

Moisture Retention and Chemical Properties of Nursery Potting Substrates

This publication provides general information about differences in moisture retention characteristics and chemical properties of most common potting substrates used by the nursery industry in south Florida. Written by Haimanote K. Bayabil, Fitsum T. Tilahun, Yuncong Li, and E. Vanessa Campoverde, and published by the UF/IFAS Department of Agricultural and Biological Engineering, October 2021.

Diversity of the genus Brasilonema (Nostocales, Cyanobacteria) in plant nurseries of central Florida (USA) with the description of three new species: B. fioreae sp. nov., B. santannae sp. nov. and B. wernerae sp. nov.

Florida is a diverse region that supports abundant cyanobacterial diversity, especially in terrestrial environments. To exploit this environment for cyanobacterial diversity, several greenhouses from central Florida were sampled to identify common nuisance and contaminating algae. Most of the algae observed were mat forming, covering nursery pots, plants, and equipment which were macro- and microscopically morphologically analogous to Brasilonema. Although macroscopic thallus morphology was similar among the samples, microscopic morphological characteristics such as size, color, and sheath formation were disparate. To uncover the cryptic diversity, mats were processed for species isolation, culture, and molecular taxonomic identification. A total of eleven Brasilonema strains were isolated into culture and systematically identified using 16S rRNA and 16S-23S rRNA ITS sequences. Based on morphology and molecular data, five species of Brasilonema were found and three are new to science: B. fioreae, B. santannae, and B. wernerae.

Alteration of media enables efficient in vitro cloning of mature Elaeocarpus serratus L. (Ceylon olive): a commercially important fruit tree.

Elaeocarpus serratus is a fruit tree able to propagate through conventional vegetative means to a limited extent restricts its wide cultivation by the farmers. In the present report, we have developed an efficient in vitro propagation protocol using mature nodal explants from a 17-year-old tree for the first time with 6.6 shoots/culture. Explants cultured on agar (0.8%) gelled standard Murashige and Skoog (MS) medium, ½ MS, ¾ MS, White's, Gamborg's B5 or woody plant medium (WPM) supplemented with 2.5µM benzyl adenine (BA) and 0.1µM α-naphthalene acetic acid (NAA) showed the superiority of ½ MS medium in terms of explant response and number shoots (6.6). Further optimization of ½ MS medium by altering nutrient elements (macros, micros, vitamins and Fe EDTA) were undertaken, and MS medium composed of half-strength major salts, original strength of minor salts and vitamins were supplemented with BA (2.5µM) and NAA (0.1µM), produced enhanced axillary bud proliferation (8.88/explant) and shoot elongation (3.83cm). Reculturing of original explant on this medium after IV passages produced more than 16 healthy shoots per culture which attained a length of 4.13cm. Microshoots raised through this way were rooted (86.11%) ex vitro by pulse treatment with 2mM indole-3-butyric acid (IBA) for 5min followed by planting in nursery pots containing a 1:1:1 (v/v/v) mix of sand, soil, and farmyard manure. The hardened plants were successfully planted in the fruit tree garden of the Department. Genetic fidelity of micropropagated and mother plants were tested using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers which showed a high degree of monomorphism thus supported morphological uniformity of micropropagated plants.

Progress of Soil Fertility and Soil Health Management Research for Arabica Coffee Production in Ethiopia

Soil degradation is one of Ethiopia's most severe concerns, contributing for the country's low coffee production. Researchers have been conducted by different organizations for the past five decades to ameliorate the challenges. The goal of this review was to summarize and document major research achievements recorded so far and recommend future research directions. As a result, mixing coffee pulp and husk in the composting pile with organic elements like farm yard manure and leguminous plants generates nutritionally high-quality compost in 45 days. In terms of increasing coffee yield, decomposed coffee husk (DCH) was found to be superior to <i>Sesbaniasesban</i> compost. Compost application rates of 5 to 10 tons ha^-1 (2 to 4 kg tree^-1 in dry weight base) and an equal proportion of soil incorporation and surface (50:50%) application techniques were found to be superior in increasing coffee yield. 50% recommended NP mineral fertilizer (RMF) (172 and 77 kg ha^-1 NP, respectively) + 50% recommended (DCH (10 ton ha^-1 or 4 kg tree^-1 on a dry weight basis), 50% RMF + 75% DCH, and <i>Desmodium</i>spp (green manure crop) + RMF (172 and 63 kg ha^-1 NP, respectively) significantly (<I>P</I>≤0.05) promote clean coffee yield at Agaro, Haru and Jimma, respectively. Forest soil or blends of top soils, compost and sand in 3:1:0 and 2:1:1 ratio, or organic manure and top soil mixture in 1:4, 2:4 and 3:4 ratios, produced strong and healthy coffee seedlings. A nursery pot amended with 750 mg P pot^-1 (2.5 kg soil) and 2.31 g lime + 250 mg P pot^-1 and 10 g lime + 800 mg P pot^-1 produced released pure line and hybrid seedlings, respectively, with superior dry matter yield at Jimma. Similarly, at Haru, an application of 4 g pot^-1 lime + 12.5 g pot^-1 DCH and 18.75 g pot^-1 DCH was a promising ameliorating management for acid soil for production of vigorous coffee seedlings for field planting. Future research should concentrate on evaluating other organic inputs and combined reclamation of lime-mineral fertilizer-compost, frequency of application, economic benefits, and long-term effects on soil physicochemical properties, coffee yield and bean quality, and establish cost effective soil fertility management in coffee-growing areas of the country. Furthermore, timely revision and calibration of mineral fertilizer recommendations made in the past with newly released coffee genotypes has become critical.

The Effect of Leaching Fraction-Based Irrigation on Fertilizer Longevity and Leachate Nutrient Content in a Greenhouse Environment

An experiment was conducted to evaluate the effects of leaching fraction (LF) on the longevity of controlled-release fertilizer (CRF) and leachate nutrient content in a pine bark substrate. The effect of LF-based irrigation was evaluated under six target LFs of 0.05, 0.15, 0.25, 0.35, 0.45, and 0.55. The 2.72 L nursery pots were filled with 100% pine bark substrate amended with dolomitic lime at a rate of 2.97 kg/m3 and Harrell’s 16-6-13 POLYON® applied at a rate of 6 g per container. Fertilizer was encased in vinyl-coated fiberglass mesh bags and subdressed 2.5 cm under the substrate surface for recovery at the end of 10 weeks. The total amount of nutrients leached from the container was greater at higher LFs, with twice as much inorganic nitrogen leached at a LF of 0.55 than a 0.15 LF. The amount of dissolved nutrients left in the substrate decreased as the LF treatments increased. There were 29.6% more inorganic nitrogen and 37.7% more phosphorus left in the substrate irrigated with a 0.15 LF as compared to a 0.55 LF. This suggests that at lower LFs, more dissolved nutrients may be available for plant uptake. No differences were seen in the amount of nutrients lost from the CRF or remaining in the prills. Results indicate that reducing the LF did not influence the longevity of POLYON® CRF in a pine bark substrate, but that a lower LF may be useful in reducing nutrient runoff into the environment. Targeting a lower LF also resulted in a larger pool of plant-available nutrients, allowing nursery producers to potentially reduce fertilizer rates.