Production Of Forest Seedlings Research Articles

Cost-effective composted municipal waste and sugarcane bagasse for forest seedling production: insights into physiological quality assessment

Cost-effective composted municipal waste and sugarcane bagasse for forest seedling production: insights into physiological quality assessment

Initial seedling development of Tectona grandis L. f. under different substrates and shading level

The management of nurseries poses a delicate task within a forest seedling production system, where quality is paramount for successful cultivation. Seedlings serve as the initiation point in the production process, exerting subsequent impacts on plant performance in the field. This study aimed to evaluate the production of Tectona grandis seedlings under varying shading levels and substrates. Six shading levels (0%, 18%, 35%, 50%, 70%, and 80%) and two substrates (Vivatto Slim Plus® and 50% Vivatto Slim Plus® + 50% sand) were stipulated. The experimental design was completely randomized with four replications of ten plants; each shading level was considered as one experiment. Seedling emergence, stem diameter, length of the largest root, height of aerial part, total length, fresh and dry biomass of aerial part and root systems, total dry biomass, and Dickson's quality index were evaluated. Direct exposure to sunlight negatively impacts the development of Tectona grandis seedlings, with 18% shading recommended. The commercial substrate Vivatto Slim Plus® proved suitable for the production of higher-quality seedlings.

Use of Trichoderma in the Production of Forest Seedlings.

Forest production has great relevance in the Brazilian economy, characterized by several production sectors, including the production of seedlings. With the focus on maximizing the capacity of survival, development, and adaptation of seedlings, Trichoderma is highlighted as a potentially useful genus of microorganisms for promoting growth and higher product quality. In this sense, this review aims to describe the main mechanisms of fungi action in forest seedlings' production. The different species of the genus Trichoderma have specific mechanisms of action, and the current scenario points to more advances in the number of species. The interaction process mediated by different mechanisms of action begins in the communication with plants, from the colonization process. After the interaction, chemical dialogues allow the plant to develop better because, from colonization, the forest seedlings can maximize height and increase shoot and root development. Fungi promote solubilization and availability of nutrients to seedlings, which show numerous benefits to the development. The use of beneficial microorganisms, such as fungi of the genus Trichoderma, has become a sustainable strategy to enhance seedling development, reducing the use of agrochemicals and industrial fertilizers.

Disease of forest tree seedlings (Article Review)

Nursery are one of the most important reasons for the success and progress of the agricultural renaissance, as it depends on the application of various advanced scientific methods and the use of Nursery of various types in the propagation and production of forest seedlings and others. A greenhouse is a place where small plants are produced to plant them in gardens, fields, and trees. The plants produced by the greenhouse vary between ornamental plants and flowers, fruit plants, vegetables, and forest trees, and Nursery are often held for commercial purposes.The incidence of Nursery diseases increases from what happens in the forests through the increase in service operations and attention to irrigation and fertilization and not sterilizing the soil and seeds, as this appears on the resulting seedlings, and the seedlings resulting from Nursery can be a source of transmission of infection when artificial afforestation is performed. Therefore, we must monitor and ensure the safety of the productive seedlings. The disease of Root rot and seedling disease Damping-off are one of the most critical diseases found in forest Nursery and the most widespread throughout the hot and cold world. As these diseases affect many forest plants, it is preferable to study them to avoid infecting forest species through the correct management of these Nursery by sterilizing the soil and seeds, as well as regular irrigation and correct fertilization.

Technical feasibility of the use of topsoil in the composition of substrates of Caatinga forest species

Mining generates great environmental impacts, in addition to a large amount of waste. In order to comply with environmental legislation, the production of seedlings is one of the actions carried out, which requires a large volume of substrates, generally commercial. The topsoil it is a residue with physical-chemical characteristics with potential for agricultural use, present in large quantities, reaching 33 thousand m3. This research aimed to know the technical feasibility of topsoil added to commercial substrate for the production of seedlings of four native Caatinga species. The experiment was carried out in a completely randomized design, in a 5 x 4 factorial model, with five topsoil levels (0, 25, 50, 75 and 100%) and four species [‘Canafístula’ (Peltophorum dubium), ‘Farinha Seca’ (Albizia hasslerii), ‘Timbaúba’ (Enterolobium contortisiliquum) and ‘Ipê Branco’ (Tabebuia roseo-alba)]. Considering the Dickson quality index, for the species ‘Canafístula’ and ‘Ipê Branco’, 74.1 and 36.1% are the maximum limits of topsoil and, for ‘Farinha Seca’ and ‘Timbaúba’, up to 100% can be used. In general, the addition of topsoil to the substrate will allow savings of 77% in substrate costs, making its use in the production of forest seedlings economically viable and environmentally correct.

The Root Collar Diameter Growth Reveals a Strong Relationship with the Height Growth of Juvenile Scots Pine Trees from Seeds Differentiated by Spectrometric Feature

This study is intended for forest owners considering options to increase the efficiency of the production of forest seedlings in automated nurseries. In the short rotation technology of the Scots pine (Pinus sylvestris L.), the production of seedlings was integrated in the process of grading seeds by spectrometric features, followed by the fall outplanting of containerized seedlings to a restorable post-pyrogenic site. There are studies of the spectrometric effect grading viable seeds, but a negligible amount of testing has been conducted on the seedling’s field performance from these seeds. It was very important for us to evaluate the morphogenesis of juvenile Scots pine trees in relation to the change in morphological features—increase in root collar diameter (RCD-increment) and increase in stem height (SH-increment)—in the second and third growing season from the field outplanting. To determine the nature of the interaction between independent (RCD increase), dependent (SH-increment), and categorical (seed spectrometric categories and timespans) variables, a regression analysis was performed using the R statistical software. All coefficients of the linear models are statistically significant at the 1% significance level, and all are positively associated with an increase in seedling height. On average, a RCD increment by 0.1 cm causes a SH-increment by 0.72 ± 0.16 cm (p = 9.779 × 10−6). In addition, in 2020, compared to 2019, the SH-increment was 5.46 ± 0.37 cm (p < 0.001). The seeds’ differentiation into spectrometric categories is strongly correlated with the stem height increment (p < 0.001). Thus, in order to improve the plant propagation protocol, it seems advisable to first condition the seeds in accordance with the spectrometric feature, and to then apply a coating (by pelleting or encapsulating) in order to improve the storage and seeding conditions. For a medium-term assessment of the short rotation technology with an integrated seed spectrometric grading in the future, the morphogenesis of Scots pine trees at 5, 7 and 10 growing seasons from the seedlings field outplanting is controlled.

Selection of climate variables by statistical-computational modeling in forest seedlings treated with growth biopromoter

Plant production requires improvement in nursery-field techniques to increase yield and economic gains. Manipulating the interaction between biotic and abiotic factors in the production of forest seedlings can improve productivity. In this context, we examined and selected the climatic variables that influence the yield of forest seedlings treated with different dosages of growth biopromoter Trichoderma sp. Climatic data were obtained from the NASA Power platform and correlated with growth data from forest seedlings treated with Trichoderma sp. The growth variables used were base diameter, height, and north-south and east-west canopy diameters. Climatic variables were selected by multiple regression models via forward-backward stepwise regression, and artificial intelligence via random forest (RF) method. The climatic variables that most influenced the growth of plants treated with Trichoderma sp. were the incidence of shortwave insolation on the horizontal surface, longwave thermal infrared radiative flux, relative air humidity, temperature, wind speed, and precipitation. Wind speed influenced only seedling height, while temperature, precipitation, and radiative flux interfered with all growth variables. Both the multiple regression and RF methods similarly describe the interaction of fungus × plant × environment. Most of the climatic variables detected via multiple regression coincided with the RF procedure. Future studies on the application of Trichoderma sp. as a biopromoter of growth should consider the identified climatic variables to optimize the production of forest seedlings in nurseries and in the field.

Forest seed and seedlings production and planted forests

In the post-war period, numerous activities were undertaken in the Republic of Srpska with the aim to renew and improve the state of seeds and seedlings production and planted forests. Among the first activities were the publishing of numerous manuals and publications, organizing seminars and conferences and carrying out organizational transformations such as the establishment of the Center for seed and seedlings production in Doboj city (as a separate organizational unit within the PFE “Šume RS”). Among the most important activities are certainly the significant financial investments related to the purchase of the equipment for the processing and the storage of seeds, as well as the container production of seedlings. Nowadays, Norway spruce, Scotch and Austrian pine seedlings (about 85% of the total number of seedlings) dominate in the production of forest seedlings in PFE “Šume RS”, which indicates that not much has changed in the established procedures of seedlings production from earlier periods. Such assortments largely do not correspond to the structure of the habitats where afforestation is carried out, nor do they correspond to the actual ecological-vegetative zoning. When referring to deciduous trees, especially from the category of valuable and rare ones, the participation of other tree species is generally small. Besides that, the ratio of the seedlings of the bare root system in relation to container seedlings has not been significantly changed till now. Practices, methods and procedures which applied for years in the production of forest seedlings have been maintained. Considering the world trends in the “target seedling production” for a previously known habitat (or buyer), the conclusions of this paper provides the recommendations and proposals, with the aim to improve seed and seedlings production (FRM) in the Republic of Srpska. With the aim of improving and increasing the success of forest establishments, activities are carried out regarding the following: adequate selection of species for afforestation, production of planting material with desirable characteristics and defining the parameters such as: planting density, habitat preparation and planting technology. Based on the new method of assessing the compatibility of habitats and species by applying the Ellenberg coefficients, a new assortment of species that needs to be produced in the Republic of Srpska in the next 30 years hasbeen defined. Dominant species are: beech (14%), fir (11%), black pine (11%), sessile oak (11%), Norway spruce (9%) and Downy oak (5%), while the remaining 39% consists of 44 different species of trees. The stress emphasis is on the use of improved planting material and on a significant increase in the participation of container seedlings (about 50%). The condition of the karst was examined and it was determined that there are large areas that are suitable for afforestation. For planting it is necessary to use the species adapted to the habitats exposed to the unfavorable effects of climatic factors. Afforestation in the Republic of Srpska can have a significantly greater success and effect if an adequate choice of species and types of planting material is made, if more attention is paid to the management of newly established forests and if afforestation is adapted to the new climate change trends.

Potential of new planting container in Quercus robur seedlings production – first report

Container production of forest seedlings needs constant improvement, so in the aim to test the new container type this research was conducted. Quercus robur seedlings were produced in the container made of natron paper and compared with seedlings produced in commonly used container types in Serbia. Q. robur seeds were sown in the first week of November 2020 in a total of 30 containers (10 of each type). After the first growing season in the nursery, on November 2021, seedlings’ morphological parameters (root collar diameter - RCD, height - H, dry weight of shoot (SDW) and root (RDW), seedling dry weight (SLDW), shoot to root ratio (S:R), sturdiness coefficient (SQ), dry weight of lateral roots (LRDW), percent of lateral roots (%LR), Dickson’s quality index (QI), root-bound index (RBI) as RBI-diameter and RBI-volume, and rooting intensity (ROIN)) were compared using one-way ANOVA. Seedlings produced in the new container showed better morphological parameters such as H, SQ, SDW, RDW, SLDW, LRDW, QI and ROIN. Differences of seedlings from different containers were not detected for H, RCD, SQ, SDW, %LR, RBI-diameter, so we can conclude that seedlings produced in the new container type are similar with other container seedlings. Larger volume of these cells indicate use for Quercus species which have strong roots. Results obtained from the nursery promote use of the new container in forest seedlings production and testing at the field.

Production of forest seedlings using sewage sludge and automated irrigation with ozonated cattle wastewater.

The large volume of effluents generated by intensive cattle production can become an environmental problem, requiring solutions that combine treatment and disposal of reuse water. The quality of cattle wastewater (CWW) treated by ozonation, the water requirement and its effect on the growth of seedlings of Dalbergia nigra cultivated with sewage sludge were determined under different light conditions. The study was carried out in a split plot scheme with 2 shading levels (0%-C1, and 49.4% attenuation-C2) and 3 types of irrigation water (control-T1, 1 h ozonation-T2, and 2 h-T3), with 4 repetitions. Direct sowing was realized into 280 cm3 tubes which were irrigated by drip irrigation with automatic management. The height and collar diameter were measured every 21 days, and at the end of the nursery phase, and the Dickson quality index (DQI) and irrigation water productivity (WPir) were determined. In addition, seedlings were transplanted in a forest restauration area (FRA) of Atlantic Forest, with height and diameter monitoring for 200 days. With ozonation, there was an increase in pH and a reduction in electrical conductivity, total solids and turbidity in the CWW, allowing its use for irrigation of forest seedlings. The maximum volumes of water applied were 2.096 and 1.921 L plant-1, with water supply T2 and T1, respectively, and coverages C1 and C2. In these conditions, the seedlings reached DQI of 0.47 and 0.17, and WPir of 2.35 and 1.48 g L-1, respectively. The initial vegetative growth of the seedlings planted in the FRA was benefited by the nutrients provided by the CWW treated. Therefore, the use of sewage sludge and CWW treated has the potential to produce forest seedlings, reducing the release of waste and effluents into the environment.

Potencial germinativo de sementes de pata-de-vaca de diferentes estádios de maturação sob temperaturas variadas

Abstract Bauhinia monandra Kurz has ornamental characteristics as the shape of its crown and the exuberance of its flowering, being and is widely cultivated in urban afforestation in Brazilian regions. The production of forest seedlings is essential not only to meet the demand of urban afforestation, but also to conserve forests. However, studies on B. monandra regarding the degree of fruit maturity on seed performance are scarce. Thus, the objective of the current work was to verify the germination potential of B. monandra seeds at different stages of maturation at five constant temperatures. The germination percentage, germination speed index (GSI), mean germination time (t), relative germination frequency, and mean germination speed (MGS) were evaluated. Initially, the mature seeds had a water content of 8.5% and the immature seeds of 68.3%. Mature seeds reached high germination percentages, above 96% for temperatures of 25, 30, and 35 ºC. The immature seeds demonstrated low germination percentages, reaching the highest percentage of 33% for the temperature of 25 ºC, followed by the temperatures of 30 ºC and 35 ºC, with respective percentages of 32% and 20%. Mature seeds demonstrated the highest GSI value (11.79) for the estimated temperature of 26.94 ºC and immature seeds the highest value of t (7.85) for the temperature of 26.56 ºC. It is concluded that mature seeds aggregate higher germination at an estimated temperature of 24.72 ºC and that immature seeds present unsatisfactory germination performance.

Development of a Biochar-Based Substrate Added with Nitrogen from a Mining Effluent for the Production of Picea mariana Seedlings

Ammoniacal nitrogen (N-NH3) is one of the pollutants that has adverse effects on the environment and is present in most effluents generated by mining operations. Therefore, mining companies must manage it to keep it below the regulated discharge criteria to avoid environmental contamination. In this context, the present study aims to valorize N-NH3 in the form of ammonium sulphate ((NH4)2SO4) for the manufacture of biochar pellets used as growth substrates for the production of forest seedlings. The biochar was first produced by fast pyrolysis, at 320 °C, and different recipes of pellets were then prepared to evaluate their hardness, binder type and content, humidity and durability. The optimal granule chosen was composed of biochar, corn starch and canola oil. Six combinations of different compositions were then prepared as substrates for black spruce growth: (1) Peat (P); (2) Peat and bulk biochar (PB); (3) Peat and bulk biochar impregnated with ammonium sulfate (PBAS); (4) Peat and biochar pellets impregnated with water (PBPeW); (5) Peat and biochar pellets impregnated with an ammonium sulfate solution (PBPeAS); (6) Peat, biochar pellets impregnated with ammonium sulfate and perlite (PBPeASPer). The effects of these substrates on the growth of black spruce seedlings, as well as fertilizer leaching, were measured. The results show that seedling biomass is equivalent to the control for the granular treatment, but higher biomass was obtained with bulk biochar (PB). This shows that a quarter of peat could be replaced by biochar to obtain similar or even better results of biomass yield and, consequently, solve part of the supply issue. As to plant nutrition, no tendency was observed for the experiments apart from the higher proportion of Ca in spruce needles. The prepared biochar-based pellet substrate appears to not only be advantageous for spruce production but also for other uses such as golf courses, forestry producers and horticultural nurseries using conventional fertilizers and peat as growing media. In addition, these approaches could help the Abitibi-Témiscamingue region in Québec, Canada to build a local circular economy.

Composted sewage sludge as an alternative substrate for forest seedlings production

The production of forest seedlings with adequate morphological and physiological characteristics is essential for the success of plantations. Substrates and irrigation are the major factors determining seedlings’ growth. Substrates made of urban and agricultural residues are a sustainable alternative to peat-based substrates. In this study, we evaluated how composted sewage sludge substrates affect the growth and gas exchange in seedlings of Cedrela fissilis Vell. Seedlings were produced under daily irrigation depths of 6, 9, and 12 mm, and on different substrates. The substrates were based on sewage sludge composted with Eucalyptus bark or sugarcane bagasse, and a commercial substrate based on peat, involving a double factorial design with 12 treatments (3 irrigation depths × 3 substrates). Both physical and chemical characteristics of substrates were analyzed, and morphological traits and gas exchanges of seedlings were measured. Sewage sludge-based substrates presented different characteristics according to the material it was mixed. Eucalyptus bark provided higher bulk density (0.19 g cm-3) and lower total porosity (75%) to the substrate, while sugarcane bagasse increased macroporosity up to 60%. Seedlings produced in sewage sludge-based substrates presented a height up to 17.8 cm and stem diameters of between 8.39-10.29 mm. Higher shoot and root dry mass was obtained in sewage sludge-based substrates with irrigation depth of 9 mm, which were 3.71 and 2.01 g, respectively. Photosynthetic carbon assimilation varied between 2.26 and 3.23 µmol CO2 m-2 s-1, and water use efficiency varied from 2.058 to 3.395 µmol CO2 (mol H2O)-1, with the highest values being obtained in seedlings produced in sewage sludge-based substrates with irrigation depth of 6 mm. Our results demonstrate that sewage sludge-based substrates are an efficient alternative to commercial peat-based substrates for seedling production.

Biological Control of Leaf Blight Disease Caused by Pestalotiopsis maculans and Growth Promotion of Quercus acutissima Carruth Container Seedlings Using Bacillus velezensis CE 100.

Leaf blight disease caused by Pestalotiopsis maculans lead to deleterious losses in the quality of forest container seedlings. The use of plant growth-promoting bacteria provides a promising strategy to simultaneously control diseases and enhance forest seedling production. This study investigated the biocontrol of leaf blight disease and growth promotion potential of Bacillus velezensis CE 100 in Quercus acutissima Carruth seedlings. B. velezensis CE 100 produced cell wall degrading enzymes, such as chitinase, β-l,3-glucanase, and protease, which caused cell wall lysis and hyphae deformation of P. maculans, leading to mycelial growth inhibition by 54.94%. Inoculation of B. velezensis CE 100 suppressed P. maculans infection and increased seedling survival rate by 1.6-fold and 1.3-fold compared to chemical fertilizer and control, respectively. In addition, B. velezensis CE 100 produced indole-3-acetic acid, which improved root development and nutrient uptake compared to chemical fertilizer and control. Especially, inoculation with B. velezensis CE 100 increased the total nitrogen content of Q. acutissima seedlings, improved the chlorophyll index in the leaves, and increased seedling biomass by 1.3-fold and 2.2-fold compared to chemical fertilizer and control, respectively. Thus, B. velezensis CE 100 could be applied in the eco-friendly production of high-quality forest seedlings.

BASE FERTILIZATION COMPENSATION AS A METHODOLOGY FOR COMPARISON OF CONTAINERS VOLUMES

The current methodology for comparing the volumetric capacity of containers does not make it possible to differentiate the effects caused by the higher concentration of fertilizers, available by volume of container, from the real effect of the growth space and fertilization. The fertilization compensation aims to correct the effect of the concentration of fertilizers, guaranteeing the same proportion of fertilization in different volumetric capacities of containers, making it possible to be a new methodology for the production of forest seedlings. The methodological proposal was applied to the production of Handroanthus ochraceus seedlings, testing two volumetric capacities, 55 and 115 cm³, of containers, of the tube type and six doses of controlled release fertilizer, namely: 0.19; 0.24; 0.30; 0.40; 0.51, and 0.63 g / tube in a completely randomized design with four replications. The height and diameter of the collection were evaluated biweekly up to 150 days after sowing and the dry matter of the aerial and root parts. The results demonstrate that regardless of the volumetric capacity of the container, the highest doses of fertilizer resulted in greater morphological characteristics. Therefore, the effect responsible for the differential growth between the volumetric capacity of the containers, normally attributed to the greater space available for root development, is actually attributed to the greater availability of nutrients, which the fertilization compensation aims to keep constant. It was concluded that the use of basic fertilization compensation proved to be efficient for comparisons between volumetric container capacities.

Практика выращивания лесного посадочного материала с закрытой корневой системой применительно к тепличным комплексам Архангельской области

The need to develop and implement innovative forms of reforestation to obtain highly productive tree stands actualize the topic of the article. The purpose of the work is to study and analyze foreign experience and research on the production of softwood containerized planting stock for reforestation and compare it with the practice of greenhouse complexes in the Arkhangelsk region. We used the international bibliographic and abstract database «Scopus», which indexes scientific journals, materials from conferences and publications to search for information. A review of publications has been completed over more than a 20-year period (1999-2019). The world experience study and the results of studies on the cultivation of forest containerized seedlings, in particular, Finland, Sweden, Norway, countries similar in terms of the growth of woody vegetation and the range of tree species to the conditions of the European north of Russia made it possible to highlight current research directions. The treatment of seedlings with a short or long light day; frost resistance of the seedlings; influence of drought, excessive moisture; issues of seedling storage; diseases, pests of seedlings and control of them, as well as problems of selection and seed production; seed quality and their impact on plant growth; influence of cultivation technology and types of planting stock on the effectiveness of planting refers to them. The use of foreign plants for growing ball-rooted planting stock implies a similar technology for the production of forest seedlings in our region. However, climatic features and the availability of various consumables, such as peat, fertilizers, pesticides, etc., necessitate the adaptation of Scandinavian technologies to local conditions and the development of additional techniques. One of the main production tasks is the achievement of standard indicators by seedlings. It is not always possible to achieve the desired results in harsh taiga conditions, therefore it is necessary to use foreign experience in growing ball-rooted planting stock, which allows to increase the production of standard seedlings without compromising their quality. This is a whole range of measures, including work on breeding and seed production, the formation of a plant substrate, lighting, moisture, observing the temperature regime, storage of seedlings, combating diseases and pests, etc., which ultimately are the components of the success of artificial reforestation

IRRIGATION FREQUENCIES FOR Eucalyptus grandis SEEDLINGS

One of the bottlenecks in relation to the production of forest seedlings is irrigation, especially in less-tech nurseries. The small volumes of substrate, where the seedlings develop, lead to low water storage. This fact can lead to water deficit and significant losses in the production of seedlings, generating even mortality. The objective of this study was to determine the best irrigation frequencies for Eucalyptus grandis seedling production in less-tech nurseries. The experiment was conducted between 2013/08/04 and 2013/23/07 (106 days) and conducted in Chapadão do Sul county, Brazil. The experiment was set up in a randomized complete block design, with five replications. Four irrigation frequencies were tested: IF1 (one daily irrigation - 11:00 a.m.), IF2 (two daily irrigations - 11:00 a.m. and 7:00 p.m.), IF3 (three daily irrigations - 07:00 a.m., 11:00 a.m. and 7:00 p.m.) and IF4 (four daily irrigations - 07:00 a.m., 11:00 a.m., 3:00 p.m. and 7:00 p.m.). The sample units were composed of eight seedlings in 50 cm3 conical tubes filled with soil and vermiculite in a volume ratio of 1:1. The irrigation depth was estimated by reference evapotranspiration (Penman-Monteith) multiplied by a crop coefficient equal to two. Plant height, number of definitive leaves, shoot dry mass (root and total), seed quality index, survival and efficiency of water use by eucalyptus seedlings were evaluated. The average daily irrigation depth in the experimental period was 5.2 mm. Based on the results, it is recommended for eucalyptus seedling producers, in less-tech nursery, irrigation management twice per days. (11:00 a.m. and 7:00 p.m.).

Sewage sludge and rice husk as potential substrate to produce Mimosa setosa seedlings

In the production of forest seedlings one of the main factors to be analyzed is the formulation of the substrate that meets the needs of the plants that will be produced. For this, the choice of substrate must consider the physical characteristics of the material, its chemical composition, as well as its availability, quality, easy handling and cost. This study aimed to investigate the potential of sewage sludge and rice husk for the production of seedlings of Mimosa setosa. The experiment was conducted in structures of a forest nursery, localized in the municipality of Alegre-ES, in 110 cm³ tubes arranged in a completely randomized design constituted by ten treatments with four replications of 54 seedlings per plot. The treatments were formulated using sewage sludge, raw rice husks and carbonized rice husk. At five months after sowing we measured plant height, root collar diameter, height/diameter ratio, shoot dry weight, root dry weight, total dry matter, shoot to root dry weight ratio and Dickson Quality Index. The substrates formulated with carbonized rice husk promoted the best results for all morphological characteristics analyzed. The multivariate analysis showed higher correlation of treatments with carbonized rice husk (T6, T7, T8 and T9) regarding height, root collar diameter, root dry weight, shoot dry weight and total dry matter. For the production of Mimosa setosa seedlings the best responses resulted from the substrate formulated with 60% sewage sludge + 40% carbonized rice husk.

Effect of biochar amendment on the properties of growing media and growth of containerized Norway spruce, Scots pine, and silver birch seedlings

Common practices and several studies have demonstrated the positive effect of biochar amendment on climate change mitigation, soil properties, and plant growth. We performed a greenhouse experiment to assess the potential of wood biochar to improve the properties of the growing media and the growth of seedlings in boreal tree species. We added willow biochar (0%, 5%, 10%, and 20%) to raw peat and measured the growth of Norway spruce (Picea abies (L.) H. Karst.), Scots pine (Pinus sylvestris L.), and silver birch (Betula pendula Roth) seedlings. In addition, the co-effect of biochar amendment with 0%, 50%, and 100% fertilization was estimated. We found that using up to 10% of biochar did not reduce the water retention capacity of the growing media significantly. Moreover, biochar amendment significantly increased carbon, nitrogen, potassium, and phosphorus concentrations and had a significant liming effect on the growing media. The biochar amendment increased the aboveground growth of spruce seedlings and root biomass, as well as the root collar diameter, of birch seedlings. Biochar amendment did not affect the quality of seedlings, estimated by the Dickson’s quality index, for spruce and pine, while the quality of birch increased. Based on our results, biochar has potential in forest seedling production.

WATER REQUIREMENTS OF Dipteryx alata VOGEL SEEDLINGS AT DIFFERENT SOLAR RADIATION LEVELS IN CERRADO-AMAZON TRANSITION

<p><strong>Background. </strong>Water and energy availability are factors that determine the maintenance, growth and development of plants and, consequently, affect its productivity. knowledge what water requirements of forest species during the initial growth stage under different energy levels are essential for technical and economic planning and the proper management of irrigation in forest nurseries, aiming at the production of healthy seedlings. <strong>Objective.</strong> The evapotranspiration potential (ETc) and crop coefficients (Kc) of baru plants (<em>Dipteryx alata</em> Vogel) were set at the early plant development stage, at increasing shading (black polyolefin screens) and spectral solar radiation levels (colored polyolefin screens), in order to subsidize irrigation and management projects focused on forest nurseries. <strong>Methodology</strong>. The experiment was conducted in the Center-Northern region of Mato Grosso State, during the dry season (from June to October 2017), for 125 days. ETc was measured through capillary lysimeters, whereas reference evapotranspiration (ETo) was set through the <em>FAO-56 Penman</em><em>-</em><em>Monteith equation</em> - Kc values were defined through the ETc/ETo ratio. Destructive growth analysis was performed 125 days after transplantation in order to determine the morphometric variables of the plants. <strong>Results.</strong> Increased shading levels decreased ETc, Kc and seedling stem diameter, besides increasing the leaf area. The herein adopted quantitative and spectral shading levels did not affect growth (in height) and dry mass accumulation in different <em>D. alata </em>seedling partitions. <strong>Implications.</strong> The results obtained allow defining improvements in the management of irrigation of forest nurseries. The adoption of irrigations systems with design errors and/or with water requirements inadequate for the production of forest seedlings may lead to yields lower than the genetic potential of the species, favor the establishment of diseases increased the consumption of nutrients and water. <strong>Conclusion.</strong>The production of <em>D. alata </em>seedlings depends on the cost-benefit ratio of shading screens and local water availability - production in full sun condition is recommended whenever water is not a limiting factor.</p>