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 Pestalotiopsismaculans 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.

Experience in the Creation of Forest Plantations Using Container Seedlings

Intensification of forestry requires the use of modern methods of reforestation, which include the introduction of container planting material. The purpose of this work is to evaluate the survival rate and linear growth of spruce container seedlings depending on the planting site location and the agrotechnical tending. The studies were carried out at the test site located in the Tomsk district of the Tomsk region. It was found that many planting containers store not 1 seedling, but 2–4 pcs and therefore approximately the same quantity of seedlings as in the traditional planting of container planting material. It was revealed that the height of 30–35 % of seedlings fails to fulfill the standard values, which was observed, as a rule, in the planting containers with several plants. According to the autumn inventory data, the height of plantations created by planting seedlings in the furrow bottom (Kruskal-Wallis test, p = 0.0001 > 0.05) reliably differs from the height of plantations of “mound” and “untreated soil” options. In terms of height growth, the options “mound side” and “furrow” have the best performance, also significantly different from the options “mound” and “untreated soil” (Kruskal-Wallis test, p = 0.0001 > 0.05). Survival rate below 85 % was observed in the plantings of the following options: “untreated soil”, “furrow bottom”, and “mound” with agrotechnical tending. The 3-fold tending decreased the survival rate of plantations except for planting in the mound side. Thus, the most successful option of planting is planting in the mound side. For citation: Debkov N.M. Experience in the Creation of Forest Plantations Using Container Seedlings. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 5, pp. 192–200. DOI: 10.37482/0536-1036-2021-5-192-200

Covering Norway spruce container seedlings with reflective shading cloth during field storage affects seedling post-planting growth

The field storage of container seedlings is often a necessity after the seedlings have been transported from nurseries close to the regeneration area. Suboptimal storage conditions can lead to reduced growth or even seedling mortality. Supporting favourable conditions for the seedlings during storage requires labour, especially for the watering of seedlings, and therefore increases the costs of forest regeneration. In this study, we examined the effects of covering Norway spruce container seedlings with a reflective shading cloth and neglecting the watering during field storage. This was done by measuring the drying of the seedlings during field storage, the rooting of the seedlings when planting, and the subsequent survival and performance in the field two and three growing seasons after planting. The study comprised one-year-old Norway spruce container seedlings covered with reflective shading cloth and seedlings with no cover (subject to rainfall) in 2012 and 2013; additionally, in 2013, replicates from both treatments were stored in conditions where rainfall was impeded. The stem water potential was measured, a rooting test was carried out, and the seedlings were planted in the test field weekly over 42 days of field storage without watering. As a novel finding, the results indicate that covering the seedlings with a reflective shading cloth during the field storage increased the risk of grey mould in summer storage and led to negative effects regarding post planting seedling development. The application of a shading cloth directly on the seedlings cannot be recommended to prolong the watering intervals during field storage in the current climatic conditions in Southern Finland, where the risk of grey mould is high.

Biochar Improves Root Growth of Sapium sebiferum (L.) Roxb. Container Seedlings

Background: The faulty development of the root system is a major threat that affects the survival rate of container seedlings of Sapium sebiferum in the transplanting and reforestation processes. The current study was conducted to determine the impact of biochar on the root growth and development of S. sebiferum container seedlings. Methods: Varied concentrations (1%, 3%, and 5%) of straw and bamboo biochar were applied in six groups, whereas the control group (CK) was only treated with matrix. Results: The treatment with 3% straw biochar (C2) proved to be the most effective soil conditioner for cultivating S. sebiferum seedlings. Moreover, C2 increased seedling height (58.92%); ground diameter (33.86%, biomass of the over-ground part (12.73 g), the underground part (7.48 g), and the fibrous part (0.076 g) compared to the CK (control). Conclusions: Biochar not only improved the root morphology by developing primary lateral roots, but it also accelerated the assimilation of N from the matrix to indirectly facilitate stem growth through enhancing NR activity. The change in root growth strategy contributed to the growth in S. sebiferum seedlings, thereby improving the survival rate during transplanting and reforestation.

Early Field Performance of Small-Sized Silver Birch and Scots Pine Container Seedlings at Different Planting Depths

Deep planting is recommended in Nordic countries only for normal-sized container seedlings planted on mounds. Its effects on smaller-sized seedlings are poorly understood. We studied the effects of planting depth on the early field performance of small-sized silver birch (Betula pendula Roth) and Scots pine (Pinus sylvestris L.) container seedlings. Silver birch seedlings (mean height of 16 cm) were planted to depths of 3, 6 and 8 cm on spot mounds in May 2016. Scots pine seedlings (mean height of 9 cm) were planted to depths of 2, 5 and 8 cm on inverted mounds in September 2018 and May 2019. At the end of the first growing season, the deeper-planted birch seedlings were the tallest, as opposed to the deeper-planted Scots pine seedlings. However, the height differences between the planting depths were not apparent until the end of the second growing season in both tree species. Deeper planting decreased damage in Scots pine seedlings in the first growing season, which was not observed in silver birch. Based on our findings, small-sized Scots pine and silver birch seedlings can be planted safely at 6–8 cm planting depths, if at least 20% and 50% of their shoots, respectively, are above ground.

Bauhinia purpurea (purple bauhinia).

B. purpurea is widely distributed throughout the Indo-Pakistan subcontinent, and has been introduced into other tropical and subtropical regions, including Africa, South-East Asia and Australia. It is a medium-size multipurpose tree, which besides timber and fuelwood provides fodder, food, tannin and gum The bark, roots and flowers have medicinal properties. B. purpurea is widely planted as an ornamental tree in parks, gardens and homesteads, and along avenues. It can be propagated by direct seeding or planting out stumps or nursery-raised container seedlings. Air layering has also given promising results.

Sesbania grandiflora (Sesbania).

Natural regeneration of S. grandiflora is rarely seen, and it is known almost exclusively as a cultivated tree. S. grandiflora can be cultivated by direct sowing, or by the planting of bare-rooted seedlings and polythene bag container seedlings.

Growth and Development of Seedlings of Scots Pine and European Spruce Container Seedlings Using Various Materials to Neutralise the Substrate

The article analyses the features of growth and development of seedlings of Scots pine and European spruce on substrates in which various materials were used to neutralise them, affecting the reaction of the environment. According to the research results, the highest germination of seeds of both woody species was established on substrates with a ratio of dolomite flour of 30% and chalk of 70%, while in the case of using pure chalk, seed germination was significantly lower. Scots pine seeds germination in the substrate ranged from 77.6% to 90.1%, and European spruce seeds – from 66.4% to 94.3%. During the cultivation of seedlings of Scots pine and European spruce container seedlings, differences in the content of mobile forms of phosphorus are noted in all variants of the experiment. However, no definite pattern was found depending on the share of participation of various types of lime material. In the substrate of seedlings of Scots pine at the end of the growing season, the content of nitrate nitrogen naturally increases from 1069.1 to 1323.6 mg/100 g of absolutely dry substrate with a decrease in the proportion of dolomite and an increase in the proportion of chalk in the lime neutralising material. Another pattern is manifested when growing seedlings of European spruce container seedlings: the lowest content of nitrate nitrogen (412.1 mg/100 g of absolutely dry substrate) is established in the case of mixing dolomite flour and chalk in equal proportions (option 3). Differences in the content of mobile forms of iron were revealed in all experimental versions of the substrate of both woody species. For the cultivation of Scots pine, its amount ranges from 16.67 to 28.81 mg/100 g of absolutely dry substrate, and European spruce – from 18.40 to 20.99 mg/100 g of absolutely dry substrate. In general, low content of mobile iron was observed in the substrate of growing pine and spruce seedlings in containers. In all experimental variants, the height of seedlings of Scots pine container seedlings exceeds the required average height of the aboveground part in accordance with national standard by 1.3-2.0 times, and for seedlings of European spruce the excess was 1.2-1.5 times. In seedlings of Scots pine and European spruce, according to the variants of the experiment, the average height of the aboveground part rises with an increase in the concentration of dolomite in the mixture of neutralising material from 50% and higher