scholarly journals Structure of forest litter in larch forests of Middle and Southern Siberia

2021 ◽  
Vol 937 (3) ◽  
pp. 032112
Author(s):  
L V Mukhortova ◽  
O V Sergeeva ◽  
L V Krivobokov ◽  
Ya S Osipenko

Abstract Forest litter plays a significant role in the functioning of forest ecosystems. As a product of forest and soil interaction, forest litter participates actively in the processes of soil formation and plant nutrition. We measured the total stock and analyzed difference in structure of forest litter formed in permafrost larch forests growing in the different climatic zones: in northern taiga of Central Siberia and in the mountain taiga of the Eastern Baikal region. The forest-forming species in both regions is Gmelin larch (Larix gmelinii (Rupr.) Rupr.), but climatic conditions and soil cover in these regions differ. It was found that average stock of forest litter is higher in mountain larch forests of the Eastern Baikal region in comparison with northern boreal forests. The litter composition in these larch forests is characterized by a relatively larger contribution of soft fractions (needles and leaves) in contrast to the larch forests in the northern taiga, where a higher contribution of hardly decomposable components (branches, cones, bark, semi-decomposed wood, thick roots, and moss residues) was observed. Higher stock of fermented plant residues in comparison with humified ones indicated the accumulation of incompletely decomposed plant residues on the soil surface of these northern forests.

1999 ◽  
Vol 79 (4) ◽  
pp. 603-613 ◽  
Author(s):  
C. A. S. Smith ◽  
C. L. Ping ◽  
C. A. Fox ◽  
H. Kodama

Soil formation under a cold, dry climate on two Late Holocene (approximately 1800 yr BP and 1150 yr BP) volcanic tephra deposits was examined to evaluate trends and rates of soil weathering. Presently under mature boreal forest, these soils are underlain by permafrost within 1 m of the soil surface. The soils are composed of buried forest floor materials and layers of coarse ashy-pumiceous rhyodacite tephra up to 60 cm thick. The bulk density in all tephra-derived horizons is less than 0.90 Mg m−3, water retention values for these horizons at 1500 kPa suction are less than 10% by weight. The mineralogy of the tephra-derived horizons is dominated by volcanic glass with lesser amounts of plagioclase, microcline and amphibole. Micromorphological investigation showed minor pitting of glass and feldspar grains and some oxyhydroxide coatings and Fe and Al-humus complexes. Several soil horizons meet glass composition, P retention and oxalate-extractable Fe and Al criteria established for andic soil material. However none of the profiles meet the thickness requirement to be classified as Andisol as specified in Soil Taxonomy. It is estimated that it would take >4000 yr under present climatic conditions to achieve such a degree of weathering. Key words: Tephra, Cryosol, andic, Yukon, Gelisol, glass


Agronomie ◽  
2002 ◽  
Vol 22 (7-8) ◽  
pp. 711-722 ◽  
Author(s):  
Axel Berkenkamp ◽  
Eckart Priesack ◽  
Jean Charles Munch
Keyword(s):  

Author(s):  
V. P. Belobrov ◽  
S. А. Yudin ◽  
V. А. Kholodov ◽  
N. V. Yaroslavtseva ◽  
N. R. Ermolaev ◽  
...  

The influence of different systems of soil cultivation is considered - traditional (recommended) technology and direct sowing, which is increasingly used under dry conditions of the region. The rehabilitation of the degraded southern chernozems and dark chestnut soils structure during 13 and 7 years of direct sowing, respectively, has not been established. It takes much longer to rehabilitation the aggregate state of soils, which is currently in a critical condition of the content of aggregates> 10 mm in size and the sum of agronomically valuable aggregates. The soils under 60-year treeline, as a control, showed a satisfactory range of aggregates, which indicates a high degree of soil degradation in the past and a long period of their recovery time. The effectiveness of direct sowing usage in the cultivation of a wider range of grain and row crops (winter wheat, sunflower, peas, chickpeas, rapeseed, buckwheat, corn) is due to the peculiarities of agricultural technologies. Abandoning of naked fallows and soil treatments with the simultaneous use of plant residues and cover crops on the soil surface between the harvest and sowing of winter crops provides an anti-erosion effect and, as a consequence, a decrease in physical evaporation, an increase in moisture and biota reserves, an increase in microbiological processes, which are noted in the form trends in improving the agrochemical and agrophysical properties of soils.


2018 ◽  
Vol 940 (10) ◽  
pp. 54-64 ◽  
Author(s):  
I.A. Belozertseva ◽  
A.A. Sorokovoj

On the basis of long-term researches of soils in the territory of Russia and Mongolia soil and ecological division into districts of the Baikal region is carried out. At division into districts the whole set of an environment of soil formation was considered. On the map of soil and ecological division into districts 13 mountain, mid-mountain, low-mountain taiga, foothill, hollow-valley, forest-steppe and steppe provinces reflecting surface device originality as the ratio of balance of heat and moisture forming a basis to zoning is shown against the background of difficult orography are allocated. In total 42 districts on lithologic-geomorphological features are allocated. In formation of distinctions of a soil cover of these provinces the leading role is played by bioclimatic factors and inside them the lithologic-geomorphological ones. In the view of structural approach of the district they are considered as territories with a certain natural change of several types of the soil cover structure caused by features of a relief and the parent rock. The map is made in the MapInfo program. It is revealed that on ill-defined width zoning of soils the vertical one which has a greater influence on soils of this region is imposed. Soils of the Baikal region are not similar to the soils located at the same latitude of the flat European territory of Russia. Zone soils of this territory are specific and original.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2015
Author(s):  
Iwona Jaskulska ◽  
Kestutis Romaneckas ◽  
Dariusz Jaskulski ◽  
Piotr Wojewódzki

Conservation agriculture has three main pillars, i.e., minimum tillage, permanent soil cover, and crop rotation. Covering the soil surface with plant residues and minimum mechanical soil disturbance can all result from introducing a strip-till one-pass (ST-OP) system. The aim of this study was to determine the impact of the ST-OP technology on the management of plant residues, soil properties, inputs, and emissions related to crop cultivation. We compared the effect of a ST-OP system against conventional tillage (CT) using a plough, and against reduced, non-ploughing tillage (RT). Four field experiments were conducted for evaluating the covering of soil with plant residues of the previous crop, soil loss on a slope exposed to surface soil runoff, soil structure and aggregate stability, occurrence of soil organisms and glomalin content, soil moisture and soil water reserve during plant sowing, labour and fuel inputs, and CO2 emissions. After sowing plants using ST-OP, 62.7–82.0% of plant residues remained on the soil surface, depending on the previous crop and row spacing. As compared with CT, the ST-OP system increased the stability of soil aggregates of 0.25–2.0 mm diameter by 12.7%, glomalin content by 0.08 g·kg−1, weight of earthworms five-fold, bacteria and fungi counts, and moisture content in the soil; meanwhile, it decreased soil loss by 2.57–6.36 t·ha−1 year−1, labour input by 114–152 min·ha−1, fuel consumption by 35.9–45.8 l·ha−1, and CO2 emissions by 98.7–125.9 kg·ha−1. Significant favourable changes, as compared with reduced tillage (RT), were also found with respect to the stability index of aggregates of 2.0–10.0 mm diameter, the number and weight of earthworms, as well as bacteria and fungi counts.


Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 309 ◽  
Author(s):  
Iván Franco-Manchón ◽  
Kauko Salo ◽  
Juan Oria-de-Rueda ◽  
José Bonet ◽  
Pablo Martín-Pinto

Natural forests and plantations of Pinus are ecologically and economically important worldwide, producing an array of goods and services, including the provision of non-wood forest products. Pinus species play an important role in Mediterranean and boreal forests. Although Pinus species seem to show an ecological adaptation to recurrent wildfires, a new era of mega fires is predicted, owing to climate changes associated with global warming. As a consequence, fungal communities, which are key players in forest ecosystems, could be strongly affected by these wildfires. The aim of this study was to observe the fungal community dynamics, and particularly the edible fungi, in maritime (Pinus pinaster Ait.), austrian pine (Pinus nigra J.F. Arnold), and scots pine (Pinus sylvestris L.) forests growing under wet Mediterranean, dry Mediterranean, and boreal climatic conditions, respectively, by comparing the mushrooms produced in severely burned Pinus forests in each area. Sporocarps were collected during the main sampling campaigns in non-burned plots, and in burned plots one year and five years after fire. A total of 182 taxa, belonging to 81 genera, were collected from the sampled plots, indicating a high level of fungal diversity in these pine forests, independent of the climatic conditions. The composition of the fungal communities was strongly affected by wildfire. Mycorrhizal taxa were impacted more severely by wildfire than the saprotrophic taxa, particularly in boreal forests—no mycorrhizal taxa were observed in the year following fire in boreal forests. Based on our observations, it seems that fungal communities of boreal P. sylvestris forests are not as adapted to high-intensity fires as the Mediterranean fungal communities of P. nigra and P. pinaster forests. This will have an impact on reducing fungal diversity and potential incomes in rural economically depressed areas that depend on income from foraged edible fungi, one of the most important non-wood forest products.


Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 323
Author(s):  
Galina Vorobieva ◽  
Nadezhda Vashukevich ◽  
Natalia Berdnikova ◽  
Ivan Berdnikov ◽  
Dmitry Zolotarev ◽  
...  

The time of Sartan glaciation in the Baikal–Yenisei Siberia, is comparable with that of MIS 2 and the deglaciation phase MIS 1. Loess loams, aeolian–colluvial sands and sandy loams represent subaerial sediments. There are four subhorizons (sr1, sr2, sr3 and sr4) in the Sartan horizon (sr). Sedimentary and soil-forming processes at different stratigraphic levels are considered. Differing soil formation types of cold periods are distinguished. Soils of the interstadial type with the A-C profile are represented only in the Early Sartan section of this paper. The soils of the pleniglacial type are discussed throughout the section. Their initial profile is O-C, TJ-C and W-C. Plant detritus remnants or poor thin humus horizons are preserved in places from the upper horizons. We propose for the first time for the interphasial soil formation type of cold stages to be distinguished. This is represented in the sections by the preserved BCm, BCg, Cm and Cg horizons of 15–20 cm thick. The upper horizons are absent in most sections. According to the surviving fragments, these were organogenous (O, TJ and T) and organomineral (AO and W) horizons. The sedimentation and soil formation features are considered from the perspective reconstruction of the Sartan natural and climatic conditions. Buried Sartan soils often contain cultural layers. Soil formation shows a well-defined periodicity of natural condition stabilization, which allowed ancient populations to adapt actively to various situations. Archaeologists’ interest in fossil soils is based on the ability of soils to “record” information about the natural and climatic conditions of human habitation.


2020 ◽  
Author(s):  
Asma Jebari ◽  
Jorge Álvaro-Fuentes ◽  
Guillermo Pardo ◽  
María Almagro ◽  
Agustin del Prado

Abstract. Temperate grasslands are of paramount importance in terms of soil organic carbon (SOC) dynamics. Globally, research on SOC dynamics has largely focused on forests, croplands and natural grasslands, while intensively managed grasslands has received much less attention. In this regard, we aimed to improve the prediction of SOC dynamics in managed grasslands under humid temperate regions. In order to do so, we modified and recalibrated the SOC model RothC, originally developed to model the turnover of SOC in arable topsoils, which requires limited amount of readily available input data. The modifications proposed for the RothC are: (1) water content up to saturation conditions in the soil water function of RothC to fit the humid temperate climatic conditions, (2) entry pools that account for particularity of exogenous organic matter (EOM) applied (e.g., ruminant excreta), (3) annual variation in the carbon inputs derived from plant residues considering both above- and below-ground plant residue and rhizodeposits components as well as their quality, and (4) the livestock treading effect (i.e., poaching damage) as a common problem in humid areas with higher annual precipitation. In the paper, we describe the basis of these modifications, carry out a simple sensitivity analysis and validate predictions against data from existing field experiments from four sites in Europe. Model performance showed that modified RothC reasonably captures well the different modifications. However, the model seems to be more sensitive to soil moisture and plant residues modifications than to the other modifications. The applied changes in RothC model could be appropriate to simulate both farm and regional SOC dynamics from managed grassland-based systems under humid temperate conditions.


2020 ◽  
Vol 12 (3) ◽  
pp. 366-372
Author(s):  
Parviz NORMATOV ◽  
◽  
Inom NORMATOV ◽  
Richard ARMSTRONG ◽  
◽  
...  

The research object. The hydrological characteristics of the Gunt and Vanch rivers belonging to the Southwestern and Central climatic zones of the Pamirs and are tributaries of the transboundary Pyanj River are considered. Long-term average values of temperature and precipitation as the main factors affecting the formation of river flows are determined for the period 1944–2016. The state of glaciation in the basins of the respective rivers is estimated. Goal. A comparative assessment of the influence of climatic features and mountain orography on the formation of river flows. Determination of the trend of changes in the climatic conditions of the Gunt and Vanch river basins at different periods of more than 70 years (1944–2016). Research methods. Generalization, systematization of meteorological and hydrological characteristics and determination of their change compared with the base period 1960–1990. Statistical processing of meteorological and hydrological data and establishing a trend of changes in climatic and hydrological characteristics using a differentiated method. Research results. It is shown that the nature of changes in hydrological characteristics, namely the flow of rivers in different climatic zones of the Pamir can differ significantly. On the example of two rivers (Gunt and Vanch) - tributaries of the transboundary Pyanj river, it is shown that the trend of change in the flow of the Gunt river differs from the Vanch river due to the state of glaciation of the river basin. To explain the results the meteorological conditions of the respective river basins and their possible impact on river hydrology were studied. Conclusion. The hydrological characteristics of the Gunt and Vanch rivers in the Pamirs taking into account the meteorological conditions of the respective river basins show that a key factor in improving the state of glaciation and reducing degradation processes, as well as achieving positive trends in the mass balance of glaciers is the presence of sufficient air mass in the glaciation zone. Naturally, this is the key to ensuring a sufficient amount of runoff.


2019 ◽  
Vol 49 ◽  
Author(s):  
José Geraldo da Silva ◽  
Adriano Stephan Nascente ◽  
Pedro Marques da Silveira

ABSTRACT The presence of straw hinders the sowing of soybean cultivated in succession to rice, in areas irrigated by flooding. This study aimed to evaluate the combination of different configurations of a rice harvester and subsequent activities in the operational and energetic demand of rice straw management and in the soil surface roughness, in order to cultivate soybean in succession. Three independent experiments were conducted in a completely randomized design, as well as evaluated the fuel consumption, effective operating speed, working capacity and final surface roughness of the ground. The energy costs of harvesting rice do not increase when the automated harvester operates with a spreader to distribute the straw on the ground and to avoid the formation of furrows. The presence of rice plant residues in the field increases the skidding of the tractor when pulling the knife-roller, with a consequent reduction of the operating speed, but this does not affect the operational capacity and the fuel consumption. The increase in the number of light harrowings, from one to two operations, in areas worked with knife-roller or intermediate harrow, requires more time and fuel in the management of the soil and rice straw, but leaves the ground with less surface roughness. The management system with knife-roller operation and two light harrowings is the most appropriate method to prepare the soil for soybean cultivation after rice, because it provides the best combination of technical and energetic performance.


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