СЕЛЬСКОЕ ХОЗЯЙСТВО. ЛЕСНОЕ ХОЗЯЙСТВО. ОХОТА. РЫБНОЕ ХОЗЯЙСТВО

Seed quality and seed germination are the major indicators determining the success of regeneration and structure in natural forest ecosystems. This study focuses on problems associated with seed quality and seed germination under air pollution impacts in the surrounding forest ecosystems of Ulaanbaatar city of Mongolia. The objectives were to test whether there was any negative effect of air pollutants on the site index, and to analyze the relationship between seed quality and distance from the city center (maximum pollution). The study was carried out in natural larch forests (Larix sibirica Ledeb.) growing in the vicinity of the capital of Mongolia. A total of eight 100×100 m (1 ha) sample plots were laid out using completely randomized sampling design along the main wind direction. Remoteness from the city center was 10, 15, 20 and 30 km both to the north and to the south. Results showed a high variation in stand mean height (p > 0.001) and diameter (p > 0.001) among selected forest areas. In general, all sampled forests belonged to bonitet / quality classes III, IV and V, which are considered as relatively poor growing conditions in terms of site index. Therefore, greater site index and seed quality were observed in the most distant locations from the city center, and contrary, the poorest seed quality was detected in locations close to the city center. This emphasizes that forests growing close to pollution sources exist with a potential risk of degradation, and their reproductive organs are more sensitive to the effects of pollutants. For citation: Udval B., Gerelbaatar S., Dashzeveg Ts., Lobanov A.I. Seed Quality of Larix sibirica Ledeb. Depending on the Distance between Forest Areas and Pollution Sources around Ulaanbaatar City of Mongolia. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 4, pp. 23–35. DOI: 10.37482/0536-1036-2021-4-23-35 Acknowledgments: This research was carried out within the framework of the project “Study of Forest Ecosystems in the Green zone of Ulaanbaatar city” and funded by the Foundation for Science and echnology. We also thank John Stanturf for the language improvement of this article.
Качество семян и их всхожесть являются главными показателями, определяющими успех восстановления и структуру естественных лесных экосистем. Основное внимание уделено проблемам, связанным с качеством семян лиственницы сибирской (Larix sibirica Ledeb.) и ее прорастанием в условиях загрязнения воздуха в окружающих лесных экосистемах города Улан-Батора. Цель работы – выявление влияния загрязнения воздуха на индекс участка и анализ взаимосвязи качества семян и расстояния от лесного участка до центра города (максимума загрязнения). Исследования проведены в естественных лиственничниках, произрастающих в окрестностях столицы Монголии. Всего было заложено восемь пробных площадей размером 100×100 м с использованием полностью рандомизированного плана отбора проб вдоль основного направления ветра. Удаленность от центра города составляла 10, 15, 20 и 30 км как на север, так и на юг. Обнаружены значительные различия средней высоты древостев (p > 0,001) и диаметра на высоте 1,3 м (p > 0,001). В целом все изученные лесонасаждения относились к III, IV и V классам бонитета, т. е. характеризовались относительно плохим состоянием с точки зрения индекса участка. Более высокие индекс участка и качество семян у Larix sibirica Ledeb. наблюдались в наиболее удаленных от центра города местах, и, наоборот, самые низкие по качеству семена были найдены недалеко от центра. Это позволяет утверждать: леса, произрастающие близко к источникам загрязнения, имеют потенциальный риск деградации, а их репродуктивные органы чувствительнее к воздействию вредных веществ, чем у деревьев, расположенных в экологически более благоприятных районах. Для цитирования: Udval B., Gerelbaatar S., Dashzeveg Ts., Lobanov A.I. Seed Quality of Larix sibirica Ledeb. Depending on the Distance between Forest Areas and Pollution Sources around Ulaanbaatar City of Mongolia // Изв. вузов. Лесн. журн. 2021. № 4. С. 23–35. DOI: 10.37482/0536-1036-2021-4-23-35

Currently, there is a high rate of urbanization, resulting in the degraded natural environment, especially the soil. The article presents the results of 25-year investigations of the silvicultural soil characteristics of the ecosystems of St. Petersburg of varying degrees of urbanization. The metropolis territory was flooded by the waters of the Littorina Sea a few million years ago. Some terraces with different levels A.S.L. after the dereliction of the sea were formed. The authors propose the urban ecosystems classification for St. Petersburg, based on the similarity of the morphological and ecological features of the biotope, and give a brief characteristic of an anthropogenic effect. The urban ecosystem soils are presented by the fill ground, contami-nated with heavy metals and compounds of sodium and chlorine and contain construction de-bris and wood residues. 4 degrees of an anthropogenic effect on the metropolis natural ecosys-tems are obtained: low-disturbed (urban forests), averagely disturbed (city parks), highly dis-turbed (gardens and parks) and degraded (line plantings and plantings of habitable territories). The boundaries of the urban ecosystems are numerous waterways. The ecological state of soil and plant resources is estimated according to a set of criteria: botanical, biochemical, soil, spa-tial and dynamic. Representative objects with laying out of at least 5 soil profiles in the specif-ic areas for each ecosystem are selected and examined. Control samples were taken from the upper soil horizons. They were the basis to establish in the laboratory the silvicultural parame-ters of the root zone in a 5-fold repeatability. The exchangeable and hydrolytic acidity, total absorbed bases, degree of base saturation, humus level, mobile nitrogen and labile phospho-rus, exchange potassium and sodium, chloride and physical clay content, humidity, soil density and a groundwater level were determined. These silvicultural parameters of the root zone of soil were compared for the selected urban ecosystems. The soils in the urban ecosystems vary according to the particle size distribution, agrochemical properties and transformation ratio of the soil profile. They are in need of the urgent measures for their improvement. A sustaining tactic of the natural ecosystems is proposed.

The research results on studying of an influence of an inoculation and mineral nitrogen application for symbiotic activity and seed production of different varieties of soya bean are presented in this article. All these researches were conducted in the All-Russia Scientific Research Institute of grain legumes and cereal crops in 2011- 2013. Symbiotic and productive ability of new soya varieties Zusha and Mezenka in comparison with the standard Lantsetnaya variety is studied. It is established that formation of the symbiotic device and its activity depended on a preseeding inoculation of seeds bacterial fertilizer (nitragin) and also on presence of spontaneous populations of rhizobium in the soil. The period duration of a symbiotic nitrogen-fixing depended on varietal features and was longer at Zusha and Mezenka's more late-season varieties. Seeds inoculation by nitragin was surpassed in efficiency of mineral nitrogen application in a dose of 60 kg per hectare. An addition yield reached 2,6 c/hectare. Different reactions of varieties when forming a crop on distribution of rainfall during the growth season was noted. Having prevalence of rainfall in the first half of summer on formation of a crop early ripening varieties which used spring soil deposits of moisture and rainfall of May-June more rationally had advantage, less suffering from a July- August drought and a heat. More late-ripening varieties had advantage in case of better providing with rains if the second half of summer. The heavy yield – 30,7 c/hectare (on average for 3 years) created Mezenka variety. doi: 10.15217/279700