15 research outputs found
Physico-chemical properties of soils associated with logged forest and areas converted to teak (Tectana grandis Linn. F)
This rapid and extensive introduction of teak to satisfy a predicted wood shortage in Ghana has given rise to the question of the short/long-term effects that management of teak plantations might have on soil properties. No research data is currently available to answer this question
Characterizing fertility targets and multi-element interactions in nursery culture of Quercus rubra seedlings
We quantified and characterized fertility targets for nursery culture of container northern red oak (Quercus rubra L.) seedlings. Plants were supplied with a 15N-5P2O5-15K2O fertilizer at eight rates ranging from 0â150 mg N plantâ1 and reared for 18 wk in a greenhouse. Plant growth and nutritional response to increased fertilization followed a curvilinear pattern depicting phases that ranged from deficiency to toxicity. Seedling dry mass production was maximized at sufficiency (25 mg N plantâ1 seasonâ1) while optimum N and P uptake occurred at 100 mg N plantâ1 seasonâ1. The 150 mg N plantâ1 seasonal dose rate induced N and P toxicity, but resulted in antagonistic K interaction. Nutrient loading raised plant N and P contents by 27 and 55%. This new approach demonstrates promise to help refine fertility targets for nursery production of Q. rubra planting stock and may have application to other hardwood species or cultural systems.CaractĂ©risation des objectifs de fertilitĂ© et des interactions multiĂ©lĂ©ments chez des semis de Quercus rubra cultivĂ©s en pĂ©piniĂšre. Des objectifs de fertilitĂ© ont Ă©tĂ© quantifiĂ©s et caractĂ©risĂ©s pour des semis de chĂȘne rouge dâAmĂ©rique (Quercus rubra L.) cultivĂ©s en pĂ©piniĂšre. Les semis ont Ă©tĂ© alimentĂ©s avec un engrais 15N-5P2O5-15K2O selon huit taux de 0â150 mg N plantâ1 et ont poussĂ©s pendant 18 semaines dans une serre. La croissance des semis, leur rĂ©ponse nutritionnelle Ă un accroissement de la fertilisation a suivi un modĂšle curvilinĂ©aire dĂ©crivant des phases rangĂ©es depuis la carence jusquâĂ la toxicitĂ©. La production en matiĂšre sĂšche des semis a Ă©tĂ© maximale Ă la dose suffisante correspondant Ă 25 mg N plantâ1 saisonâ1, tandis que lâoptimum de consommation sâest situĂ© Ă 100 mg N plantâ1 saisonâ1. La dose saisonniĂšre de 150 mg N plantâ1a induit une toxicitĂ© N et P, mais il en est rĂ©sultĂ© une interaction antagoniste avec K. Le prĂ©lĂšvement de nutriments par les plants a augmentĂ© le contenu en N et P de 27 % et 55 %. Cette nouvelle approche dĂ©montre la possibilitĂ© dâespĂ©rer perfectionner les objectifs de fertilitĂ© pour une production en pĂ©piniĂšre de plants de Quercus rubra et peuvent avoir une application pour dâautres espĂšces feuillues et dâautres systĂšmes culturaux
Characterizing fertility targets and multi-element interactions in nursery culture of Quercus rubra
Drought susceptibility and recovery of transplanted Quercus rubra seedlings in relation to root system morphology
âąâ Transplant shock, implicated by depressed seedling physiological status associated with moisture stress immediately following planting, limits early plantation establishment. Large root volume has potential to alleviate transplant shock because of higher root growth potential and greater access to soil water.
âąâWe investigated impacts of drought and transplant on photosynthetic assimilation (), transpiration (), stomatal conductance , predawn leaf xylem water potential , and growth of northern red oak (Quercus rubra L.) seedlings to explain mechanisms associated with susceptibility to transplant shock. One year-old barerooot seedlings were graded into four categories and either well watered or subjected to drought consisting of low, medium, or high moisture stress by discontinuing irrigation at 22-day intervals for 3 months. Thereafter, all treatments were re-watered to examine recovery.
âąâTransplant shock was signified by reduced , , , and , which generally increased with increasing moisture stress and . Physiological status improved during recovery, though stress was still evident in seedlings exposed to medium or high moisture stress and in larger seedlings. Growth declined with increasing moisture stress but was generally similar among treatments, likely reflecting greater at the whole plant level and/or reliance upon stored reserves in large seedlings.
âąâThe most effective drought avoidance mechanisms were root growth, stomatal regulation, reduced leaf area, and higher growth allocation to roots relative to shoots. Our results suggest that large initial does not enhance drought avoidance during the first season after transplant in northern red oak seedlings.SensibilitĂ© Ă la sĂ©cheresse et reprise
des semis transplantĂ©s de Quercus rubra en relation avec la morphologie racinaire. âąâLe choc de transplantation, liĂ© Ă l'Ă©tat physiologique
déprimé des plants associé à un stress hydrique,
immédiatement aprÚs la plantation, limite le début de
l'installation des plants. Un important volume racinaire () a le potentiel
d'atténuer le choc de transplantation en raison du fort potentiel de
croissance racinaire et d'un meilleur accĂšs Ă l'eau du sol.
Nous avons étudié les impacts de la sécheresse et des
transplants sur l'assimilation photosynthétique (), la transpiration
(), la conductance stomatique , le potentiel hydrique de base
, et la croissance des plants de chĂȘne rouge (Quercus rubra L.) pour
expliquer les mécanismes associés à la sensibilité à un
choc de transplantation. Des plants de un an Ă racines nues ont
été classés en quatre catégories et soit bien
arrosés, ou soumis à une sécheresse, consistant à un faible,
moyen ou fort stress hydrique en cessant l'irrigation Ă
22 jours d'intervalle(27, 49 et 72 aprĂšs la transplantation) pour 3
mois. Par la suite, tous les traitements ont été arrosés afin
d'examiner la reprise.
âąâLe choc de transplantation qui gĂ©nĂ©ralement a augmentĂ© avec
l'augmentation du stress hydrique et , a été significatif par la
réduction de , , , and . L'état physiologique
s'est amĂ©liorĂ© lors de la reprise, mĂȘme si le stress est encore
évident chez les plants exposés à un stress hydrique moyen ou
élevé et chez les plants à les plus importants. La croissance
a diminué avec l'augmentation du stress hydrique, mais elle a
été généralement similaire chez les traitements ,
reflétant probablement une plus grande au niveau du plant entier et /
ou le recours Ă des rĂ©serves stockĂ©es dans les plants Ă
important. âąâLes mĂ©canismes d'Ă©vitement de la sĂ©cheresse les plus efficaces
ont été la croissance des racines, la régulation stomatique, une
surface foliaire réduite et une allocation de la croissance plus
élevée aux racines par rapport aux pousses. Nos résultats
suggÚrent que les grandes initiales n'améliorent pas
l'évitement de la sécheresse durant la premiÚre saison aprÚs
transplantation chez les plants de chĂȘne rouge
Nitrogen Recovery from Enhanced Efficiency Fertilizers and Urea in Intensively Managed Black Walnut (Juglans nigra) Plantations
Intensively managed forest plantations often require fertilization to maintain site fertility and to improve growth and yield over successive rotations. We applied urea-based âenhanced-efficiency fertilizersâ (EEF) containing 0.5 atom% 15N at a rate of 224 kg N haâ1 to soils under mid-rotation black walnut (Juglans nigra L.) plantations to track the fate of applied 15N within aboveground ecosystem components during the 12-month period after application. Treatments included Agrotain Ultra (urea coated with a urease inhibitor), Arborite EC (urea coated with water-soluble boron and phosphate), Agrium ESN (polymer-coated urea), uncoated urea, and an unfertilized control. Agrotain Ultra and Arborite EC increased N concentrations of competing vegetation within one month after fertilization, while neither Agrium ESN nor uncoated urea had any effect on competing vegetation N concentrations during the experiment. Agrotain Ultra and Arborite EC increased ÎŽ15N values in leaves of crop trees above those of controls at one and two months after fertilization, respectively. By contrast, Agrium ESN and uncoated urea had no effect on ÎŽ15N values in leaves of crop trees until three months after fertilization. Fertilizer N recovery (FNR) varied among ecosystem components, with competing vegetation acting as a sink for applied nutrients. There were no significant differences in FNR for all the urea-based EEF products compared to uncoated urea. Agrium ESN was the only EEF that exhibited controlled-release activity in this study, with other fertilizers behaving similarly to uncoated urea
Late-season fertilization of Picea mariana seedlings: intensive loading and outplanting response on greenhouse bioassays
Traditional greenhouse culture involves a late-season hardening period that withholds irrigation and fertilization from black spruce seedlings to promote frost-hardiness. Since nutrient uptake is limited without supplemental fertilization, growth during hardening may lead to internal nutrient dilution, a condition detrimental to field performance of seedlings. We examine whether late-season fertilization, applied as intensive loading, will counter dilution and build up nutrient reserves in seedlings reared conventionally or nutrient loaded before hardening. A mixed NPK fertilizer delivering 0, 12, 24, or, 48 mg N·seedlingâ1 for 9 weeks after bud set was tested. Root and shoot dry mass increased as much as 104 and 42% during hardening. Seedling biomass, however, was unchanged by late-season fertilization, but N uptake was increased 44â167% signifying induced luxury consumption. Extra K supplementation of treatments averted K dilution in plant tissues often occurring with high N addition. A 13-week outplanting trial on intact soil bioassays retrieved from a boreal site showed that growth and nutrient allocation were significantly enhanced by larger N reserves built up after intensive nutrient loading. About 72â80% of N required for new shoot growth was met from internal cycling, demonstrating the capacity of loading to enhance retranslocation. Intermediate loading (24 mg N) was most effective in promoting N accumulation and outplanting growth of both seedling types. Survival was reduced (30%) only at the highest dose. Study results demonstrate the potential advantage of these practices to improve growth of newly planted seedlings on northern forest sites.Fertilisation tardive de semis de Picea mariana : apport intensif et rĂ©ponse aprĂšs plantation en serre dâessais biologiques. Les cultures traditionnelles en serre comportent une pĂ©riode tardive dâendurcissement qui retarde lâirrigation et la fertilisation des semis de Picea mariana pour promouvoir lâendurcissement au froid. Puisque le prĂ©lĂšvement de nutriments est limitĂ© sans supplĂ©mentation de fertilisation, la croissance pendant la pĂ©riode dâendurcissement peut conduire Ă une dilution interne des nutriments, une situation prĂ©judiciable pour les performances au champ des plants. Nous avons examinĂ© si la fertilisation tardive, appliquĂ©e par des apports massifs peut contrebalancer la dilution et accroĂźtre les rĂ©serves de nutriments dans les semis Ă©levĂ©s conventionnellement ou les nutriments apportĂ©s avant lâendurcissement. On a testĂ© un mĂ©lange de fertilisant NPK libĂ©rant 0,12, 24 ou 48 mg dâazote par semis pendant 9 semaines aprĂšs le dĂ©bourrement. Le poids sec des racines et des pousses sâest accru de 104 et 42 % pendant lâendurcissement. Cependant la biomasse des semis a Ă©tĂ© inchangĂ©e par une fertilisation tardive, mais le prĂ©lĂšvement dâazote sâest accru de 44 Ă 167 %, indiquant une consommation de luxe. Une supplĂ©mentation en K Ă©vite une dilution en K des tissus, ce qui arrive souvent avec un apport important dâazote. Un essai Ă 13 semaines sur un sol pour essais biologiques, extrait dâune station borĂ©ale, a montrĂ© que la croissance et lâallocation des nutriments Ă©taient significativement augmentĂ©es par de grandes rĂ©serves dâazote accumulĂ© aprĂšs des apports intensifs de nutriments. Environ 72 Ă 80 % de N requis pour la croissance des nouvelles pousses provenaient du cycle interne, dĂ©montrant lâimportance des apports pour augmenter les retranslocations. Un apport intermĂ©diaire (24 mg N) Ă©tait plus efficace pour promouvoir lâaccumulation de N et la croissance des deux types de semis. La survie a Ă©tĂ© rĂ©duite (30 %) seulement pour la plus forte dose. Les rĂ©sultats de cette Ă©tude ont dĂ©montrĂ© lâavantage potentiel de ces pratiques pour lâamĂ©lioration de la croissance des semis dans les stations forestiĂšres du Nord
Performance of Nutrient-Loaded Red Oak and White Oak Seedlings on Mine Lands in Southern Indiana
ABS TR ACT Exponential nutrient loading was used to build nutrient reserves in northern red oak (Quercus rubra) and white oak (Q. alba) seedlings during standard bareroot nursery culture at the Vallonia State Nursery, Indiana. Nursery grown seedlings were outplanted the following year onto a mine reclamation site in southern Indiana to evaluate effects of prior nursery treatments on field performance. At the nursery stage, exponential nutrient loading improved plant dry mass production. Nutrient loading increased nitrogen uptake 40% in red oak and 35% in white oak when compared to controls. When outplanted, exponential nutrient loading enhanced shoot height and root collar diameter response in the studied species. White oak seedling survival was 92%, compared with 83% for red oak in year 1. Survival decreased to about 74% for white oak and 65% for red oak in year 2. Results suggest exponential nutrient loading has potential to promote seedling performance on harsh site conditions, and are significant for reclamation efforts in Indiana and across the US. Fertilization at planting, in combination with weed control with herbicides, can alleviate poor site fertility, reduce competition, and enhance seedling field survival and growth (Jacobs and others 2005). However, there is public sentiment against herbicide use in forests owing to potential negative impacts on the environment and on biodiversity KEYWORDS Several fertilization methods, such as conventional, exponential, or nutrient-loading models, can be used to nutritionally pre-condition plants at the nursery stage for outplanting. Conventional fertilization involves application of equal fertilizer doses at regularly spaced intervals throughout the growing season. This approach creates a surplus of nutrients to young seedlings early in the growth phase, but may cause a deficiency in larger seedlings by the end of the growing season Although the above fertilization techniques may have universal application, protocols to determine optimal target rates associated with maximum growth and seedling nutrient storage are not well defined. There is apparent need to quantify target rates for each species and cultural system owing to differences in species demand for nutrients and variations in cultural conditions. An innovative approach that can help rationalize and quantify fertility targets in tree seedling culture is illustrated in USDA Forest Service Proceedings :: RMRS-P-57 :: 2008 67 Nutrient-loaded seedlings exhibit greater survival, growth, and competitiveness over nonloaded plants on a variety of habitats Materials and Methods Nursery Phase Bareroot northern red oak and white oak seedlings were grown from seeds germinated in spring 2004 at Vallonia State Nursery, Indiana (38°85'N, 86°10'W). Seedlings were fertilized conventionally or exponentially using 10 fertility treatments that ranged from deficiency to toxicity (0 to 3.35 g N/plant/season). Higher fertility treatments were intended to build nutrient reserves in plants for later utilization when outplanted. Nitrogen was applied bi-weekly as ammonium nitrate in crystal form (34N:0P 2 O 5 :0K 2 O). Further details on the nursery study can be found in Birge and others (2006). Seedlings were mechanically lifted in December 2004 and processed for overwinter Field Study Nursery-reared seedlings were outplanted in April 2005 into an abandoned mine reclamation site in southern Indiana. The field design was a split-plot design with a 2 x 10 factorial treatment structure, and was replicated in 5 blocks. The main plot treatments were species at 2 levels and the sub-plot treatments were the 10 nursery fertility treatments. Each block measured 21 x 42 m (69 x 138 ft) and was separated from the next by 2-m (6.5-ft) buffers. Species were randomly allocated within blocks, and fertility treatments were randomly allocated within species. Each treatment consisted of 20 trees in one row within a block, and each block contained 20 rows. A total of 2500 seedlings were planted and monitored in this 68 USDA Forest Service Proceedings :: RMRS-P-57 :: 2008 experiment (10 treatments x 20 trees per treatment x 2 species x 5 replications). Trees were planted 1 x 1 m (3.3 x 3.3 ft) within rows and 2 x 2 m (6.5 x 6.5 ft) between rows. Sampling and quantification of seedling morphological and nutritional responses followed standard protocols Results and Discussion Nursery Phase Growth and nutritional data sampled at the end of nursery culture (Birge and others 2006) conformed closely to trends shown in Field Response Generally, field survival was high in year 1 Conclusions Storing nutrients in seedlings at the nursery stage provides a better rationale to promote seedling field performance. Higher pre-plant nutrient reserves have potential to reduce competitive effects and enhance internal redistribution to support new growth soon after outplanting. High survival and growth of competitive nutrientloaded seedlings will accelerate forest restoration success on degraded landscapes, which will help to conserve soil resources as well as provide habi- tat for wildlife. Early rapid growth will allow plants to reach free-to-grow status sooner and minimize potential for animal browse. Use of competitive nutrient-loaded seedlings will accelerate early growth and minimize the need to control competing vegetation with herbicides. The use of balanced fertilizer is key to successful nutrient loading. Frequent and light applications will make nutrients readily available to plants. This increases uptake efficiency and minimizes potential leaching losses associated with heavy and less frequent applications
Growth, physiology, and nutrient retranslocation in nitrogen-15 fertilized Quercus rubra seedlings
We evaluated gas exchange, chlorophyll index (CI) using SPAD-502 chlorophyll
meter, and leaf nutritional responses in one-year-old northern red oak
(Quercus rubra L.) container seedlings transplanted into control (unfertilized) or
fertilized (0.86 g N plant sand culture and grown in a greenhouse
for 90 days. We labeled current nitrogen (N) uptake with (NHSO and directly quantified proportional
contributions of N derived from fertilizer (NF) compared with
retranslocation or N derived from plant (NP) in leaf growth of red oak
seedlings. NF met a greater N demand in leaf growth of fertilized plants
while unfertilized seedlings relied entirely on NP for their leaf growth.
Fertilization increased leaf dry mass by 67% and new stem dry mass by 253%
90 days after transplanting compared to control seedlings. Specific leaf
area (SLA) was not significantly altered but CI increased 90 days after
transplanting. Higher leaf N concentration and content in fertilized
compared with control seedlings was linked to greater chlorophyll
concentrations in the former plants. The higher coefficient of determination
( = 0.72) noted between leaf N concentrations and CI suggests that
the SPAD meter could be a useful tool for assessing leaf N status in
northern red oak seedlings. Fertilized seedlings exhibited higher net
assimilation, stomatal conductance, and transpiration rates
compared with controls. Increased seedling growth in response to
fertilization was related to maintenance of higher gas exchange and greater
nutrient uptake, which could improve outplanting success.Croissance, échanges gazeux et réponses nutritionnelles de jeunes
semis de Quercus rubra soumis à une fertilisation par (NHSO. Nous avons estimé les échanges gazeux foliaires, un index de teneurs
en chlorophylles (IC) avec un chlorophylle-mĂštre SPAD-502 et les teneurs
en nutriments dans les feuilles de jeunes plants de chĂȘne rouge
d'Amérique (Quercus rubra L.) ùgés d'un an. Les plants ont été
transplantés dans du substrat sableux non fertilisé (témoins) ou
fertilisé avec 0.86 g N par plante, et cultivés pendant 90 jours
sous serre. L'azote apporté par la fertilisation était marqué
avec (NHSO et nous avons directement quantifié
les contributions à la croissance foliaire de N apporté par la
fertilisation (NF) par rapport à celle de N remobilisé depuis les
pools de réserve de la plante (NP). NF constituait la fraction la plus
importante d'azote foliaire de plants fertilisés, alors que l'azote
foliaire des plants non fertilisés était exclusivement constitué
de NP. La fertilisation s'est traduite par une augmentation, par rapport aux
plantes témoins, de 67 % de la biomasse foliaire et de 253 % de la
biomasse de tiges nouvellement formées 90 jours aprÚs la
transplantation. La surface spécifique des feuilles n'était pas
affectée par la fertilisation alors que CI avait significativement
augmenté. Des teneurs plus élevées en N foliaire en comparaison
des témoins, étaient donc liées à des concentrations plus
fortes en chlorophylles. Le coefficient de détermination élevé
( = 0.72) des relations entre concentration de N et CI montrent que le SPAD-502 pourrait ĂȘtre un instrument utile pour l'Ă©valuation des
teneurs en N dans des semis de chĂȘne rouge. Les semis fertilisĂ©s
présentaient également des niveaux d'assimilation nette de CO,
de conductance stomatique et de transpiration plus élevés que les
plants tĂ©moins. La croissance plus forte des semis en rĂ©ponse Ă
la fertilisation était liée à des échanges gazeux plus
actifs et une plus forte assimilation de nutriments, ce qui peut augmenter
les chances de succĂšs Ă la transplantation en forĂȘt