Model Selection for Ecosystem Respiration Needs to Be Site Specific: Lessons from Grasslands on the Mongolian Plateau

Selecting an appropriate model for simulating ecosystem respiration is critical in modeling the carbon cycle of terrestrial ecosystems due to their magnitude and high variations in time and space. There is no consensus on the ideal model for estimating ecosystem respiration in different ecosystems. We evaluated the performances of six respiration models, including Arrhenius, logistic, Gamma, Martin, Concilio, and time series model, against measured ecosystem respiration during 2014–2018 in four grassland ecosystems on the Mongolian Plateau: shrubland, dry steppe, temperate steppe, and meadow ecosystems. Ecosystem respiration increased exponentially with soil temperature within an apparent threshold of ~19.62 °C at shrubland, ~16.05 °C at dry steppe, ~16.92 °C at temperate steppe, and ~15.03 °C at meadow. The six models explained approximately 50–80% of the variabilities of ecosystem respiration during the study period. Both soil temperature and soil moisture played considerable roles in simulating ecosystem respiration with R square, ranging from 0.5 to 0.8. The Martin model performed better than the other models, with a relatively high R square, i.e., R2 = 0.68 at shrubland, R2 = 0.57 at dry steppe, R2 = 0.74 at temperate steppe, and R2 = 0.81 at meadow. These models achieved good performance for around 50–80% of the simulations. No single model performs best for all four grassland types, while each model appears suitable for at least one type of ecosystem. Models that oil moisture include models, especially the Martin model, are more suitable for the accurate prediction of ecosystem respiration than Ts-only models for the four grassland ecosystems.

Longevity of Ulmus pumila L. in protective afforestation on semi-desert lands of the Astrakhan Zavolzhye

The article provides a predictive assessment of longevity of Ulmus pumila L. stands in the Astrakhan Zavolzhye. The effi and expediency of renewable logging for rejuvenation and increasing the longevity of plantings in the semi-desert were confi The classifi of ecotopes of the Astrakhan Zavolzhye on suitability for cultivation of protective and shadow elm plantings on pasture lands was developed and presented. In the Caspian region, Ulmus pumila became widespread in forest reclamation of semi-desert lands in the 1950s. Since then, till the beginning of the 1990s, Bogdinskaya research agroforestry experimental station laid on the sandy massifs about 1 thousand hectares of Ulmus pumila L. plantings, which currently amounts to 1824 %. The long-term practice of using protective shade Ulmus pumila umbrellas has shown their signifi ecological effect on functioning pastures. The aim of the research was to develop an improved technology for creating long-lived protective shade stands of Ulmus pumila on degraded pastures of the Astrakhan Zavolzhye. The research was carried out using generally accepted methods of stand forest taxation by A.P. Anuchin (1961), 1. Bitvinskas (1974) and A.S. Manaenkov (2001). Soil conditions were studied by drilling sounding to 3 m depth. The results of the research revealed that the longevity of wood species in the dry-steppe zone was determined mainly by two factors: productive moisture in the soil and salinity level. The most favorable growing conditions for Ulmus pumila were unsalted (to a depth of at least 3 m) brown sandy soils, sandy loam soils, dark-colored swale soils with periodic redistributed accumulation of moisture. In arid conditions of the Astrakhan Zavolzhye in island plantations (group of trees, umbrellas, 0.51 ha parts of forest area) and optimal growing conditions without logging and reforestation, Ulmus pumila lives up to 6070 years.

APPLICATION OF LANDSCAPE-GEOCHEMICAL APPROACH IN THE STUDY OF THE TERRITORY OF THE NORTH KAZAKHSTAN REGION

The article discusses the issues of assessing the ecological condition of agricultural lands in the border territory of the North Kazakhstan region and identifying the necessary measures to optimize the existing structure of land use. The border area under study is located in the zone of dry-steppe and steppe landscapes, among which dry-steppe landscapes of relatively elevated plains predominate.

Cutivation of grasses as the basis for arable farming biologization and forage production optimization under various conditions of the south of Central Siberia

На примере трёх агроэкологических районов Хакасии показано влияние почвенно-климатических и ландшафтных особенностей территории на структуру растениеводства и развитие животноводства. Основные посевные площади в республике занимают зерновые и кормовые культуры. За период 2000–2019 годов относительно 1990 года произошло уменьшение посевных площадей по республике в 2,6 раза, по агроэкологическим районам — соответственно в 2,3; 2,3 и 1,6 раза. Доля кормовых культур в структуре посевов по Хакасии за 2000–2019 годы составляет 51,9%, в сухостепном — 79,5%, степном и лесостепном районах — 48,3 и 48,5%. Показатели плодородия почвы по содержанию гумуса показывают, что в республике в целом почвы пашни содержат 4,7% гумуса, наименьшее содержание — в сухостепном районе (3,5%). В настоящее время 84,6% пахотных земель характеризуются низкой и средней обеспеченностью подвижным фосфором. Поэтому переход земледелия на биологическую основу предусматривает восстановление деградированных агроландшафтов и сохранение плодородных свойств почв за счёт широкого внедрения травосеяния. Среди кормовых культур за период 2000–2019 годов на однолетние травы приходится по республике 27,6% и по районам — 18,0, 29,8, 36,3%; на многолетние травы — соответственно 63,1, 82,0, 52,5, 56,3%. В республике в 2019 году естественные сенокосы составили 160,4 тыс. га (8,3%), пастбища — 1019,8 тыс. га (53,3%). Их состояние требует проведения комплекса мероприятий, включающих использование технологий поверхностного и коренного улучшения. Для увеличения посевов трав необходимо существенное улучшение состояния семеноводства. Для повышения эффективности семеноводства однолетних и многолетних трав в республике необходим комплекс мер по совершенствованию форм его организации и специализации для создания единой системы размножения, начиная с питомника первичного семеноводства суперэлитных, элитных и репродукционных семян. The effect of the environment of three districts in Khakassia was tested on crop production and animal husbandry. Most farm lands are occupied by grain and forage crops in the Republic of Khakassia. In comparison to 1990 farm land area decreased by 2.6 times there for 2000–2019 as well as by 2.3, 2.3 and 1.6 times — in the districts studied, respectively. Forage crop proportion amounted to 51.9% for 2000–2019, in the dry steppe — 79.5%, steppe and forest steppe — 48.3 and 48.5%. Farm lands contained 4.7% of humus, the lowest concentration being in the dry steppe (3.5%). Currently 84.6% of farm lands show average to low content of soluble phosphorus. Biologization of arable farming will be focused on land restoration and maintaining soil fertility via the introduction of wide range of grasses. The proportion of annual forage grasses totally amounted to 27,6% for 2000–2019, in the districts — 18.0, 29.8, and 36.3%; perennial grasses — 63.1, 82.0, 52.5, 56.3%, respectively. In 2019 the acreage of natural haylands amounted to 160.4 thousand ha (8.3%), pastures — 1019.8 thousand ha (53.3%). The poor condition of farm lands requires the complex of effective tillage techniques. To increase the area of grass cultivation improved seed production is needed. Optimization of seed production includes the development of a unified reproduction technology starting from a nursery of primary seed growing.

Agroecology of Goychay District’s Soils of Azerbaijan

Goychay region has very suitable and unique lands for strategic agroecological monitoring. A dry steppe and semi-desert zone, which is characterized by a pronounced arid climate, is located at an altitude of 200–400 m above sea level, where the dominant soils in the territory are various subgroups of gray-brown soils and serozem types. The fact that soil studies in the Goychay region of the Azerbaijan Republic are less studied than in other regions, and there is no literature, is an innovative and urgent problem for soil scientists. The article presents some of the results of seasonal surveys, ecological expertise and biological diagnostics carried out in recent years. Biological diagnostics, environmental monitoring and assessment of these soils by modern methods are of great innovative importance for the development of agriculture in Azerbaijan. As a result of many years of agroecology research, the involvement of natural cenoses in agriculture has created conditions for obtaining high productivity from these soils

ACCUMULATION OF IRON AND MANGANESE IN THE LEAVES OF PINE PINE AND HERBAL COVER OF THE BESKARAGAY TAPE BORON OF KAZASTAN

The paper presents materials on the study and content of the accumulation of iron and manganese in the woody and herbaceous leaves of the Beskaragai belt pine forest of the dry steppe zone of Kazakhstan, as well as the ratio of iron and manganese to determine the conditions for normal plant life. The results of the research showed that the values of the biotic index in woody and herbaceous plants of the Beskaragay lentchen boron for iron are below 0.3. In the needles of pine trees, none of the zones retained the ratio between iron and manganese for the normal life of pine plants. The accumulation of manganese in herbs occurs mainly from the atmosphere. Of the two biogenic metals, only Mn in the Beskaragai pine forest plays the role of biogeochemical circulation of substances for pine needles. The values of Кн for iron are less than one in pine needles taken from different zones of the Beskaragai forest, which indicates the input of manganese into forest ecosystems, both from the soil and from the atmosphere. The ratio of the concentration of iron and manganese 2: 1, which is necessary for grasses for normal life, is observed only in the zone of unpaved roads of the Beskaragai forest. The work is of great importance for further monitoring of the state of forest ecosystems in the conditions of technogenic and aeronautical pollution of the study area.

Treatments influence on soil water-physical indicators in Nizhneje Povolzhje dry-steppe zone conditions

The experiment is carried out in the conditions of semi-desert flat agricultural landscapes of light chestnut soils. The object of research is a 4-field crop rotation (factor A), variants of the main tillage (factor B) and crops superimposed on the tillage options with the Don-114 seeder (a seeder for direct sowing). The placement of options (A) is sequential and options (B) are arranged in blocks in three tiers. The main soil tillage was carried out by the following tools: mouldboard tillage to the depth of 25-27 cm by plough PN-4-35; non-mouldboard tillage to the depth of 25-27 cm by the tool OCHO-5-40 with the rack “Rancho”; surface one to the depth of 8-10 cm by the tool BDM-4.2, and 4-field grain-fallow crop It was found that a higher content of nutrients is in fallow preferably at non-mouldboard soil treatment, in some years, which has an optimal moisture supply, and control (mouldboard) one in comparison with lower levels of surface soil treatment in all years of the research. The main comparison in the change in nutrients in fallow fields is observed precisely for different methods of soil cultivation.

Efficiency of forest planting in the spring and autumn periods in the conditions of the Republic of Kalmykia

The Republic of Kalmykia is the driest region in the south of the European part of Russia. The purpose of the study is to find a new approach to reforestation and breeding in the republic, which will ensure the increase in the survival rate of forest crops, and subsequently increase the forest cover of the region. The article analyzes data for a ten-year period in a zonal section on the survival rate of tree and shrub species cultivated in the forestry of the Republic of Kalmykia. It is concluded that carrying out forest cultivation works in the autumn period has no advantages in survival rate over the spring period and they should be carried out either in early spring (in late March and early April) on thawing soil, or in autumn, before the onset of persistent cold weather. The main factor of successful afforestation in the dry steppe and semi-desert is the correct selection of the forest area, the accuracy and quality of forest planting, agrotechnical and forestry care. Special attention should be paid to the control of locust pests, which in the conditions of Kalmykia in some years can cause significant damage to the planting of young forest crops.

Advanced technologies for the creation of forest cultures in the southern regions with arid climate

The article analyzes the of the drip irrigation and biologically active substances fertilization use effectiveness in forestry in arid regions; the main advantages and disadvantages of drip irrigation for protective afforestation in dry steppe and semi-desert are indicated, the conclusion about the possibility of its use in the creation of forest crops with economic feasibility, the availability of infrastructure (a water source with water suitable for irrigation, power lines) is made. The use of drip irrigation is advisable when planting plantations of particular value (forest seed plantations, walnut groves, orchards, landscaping plantings in recreational areas, etc.). However, for an unambiguous answer, it is necessary to lay experimental crops in different soil and hydrological conditions, with different types and mixing schemes, woody and shrub species composition, to develop irrigation and watering norms, to test the latest biological preparations that improve the processes of root formation, growth, and resistance to diseases and environmental stressors.

Effectiveness of biologization predecessors and methods in increasing grain crops productivity and field crop rotations productivity in Nizhneje Povolzhje region

Researches on the study of predecessors and biologization techniques in field crop rotations were carried out in 2018-2020 in the dry steppe zone of the chestnut subzone of light chestnut soils of the Nizhneje Povolzhje region. It is necessary to grow biennial melilot for green manure as a fallow-growing crop in a grain-steam five-field crop rotation in order to increase the organic matter input into the soil. A significant increase in yield was achieved in chickpeas for winter wheat, its straw was plowed into the soil. The highest increase in the spring barley yield was provided during the chickpeas and sorghum cultivation, which straw entered the soil. When growing spring barley on safflower, its straw was plowed into the soil, the yield was also higher than the control variant. The highest grain yield was achieved in the control grain-fallow four-field crop rotation with complete fallow, where the cultivated crops straw was removed from the field and grain-fallow-grass green manure seven-field crop rotation with seed fallow, where straw and melilot were plowed into the soil. Grain-fallow seven-field and grain-fallow-grass-cultivated green manure seven-field crop rotations, where oats and phacelia straw and green manure mass entered the soil, were inferior to the control.