No-tillage implementation: Analyzis on water-based sediment flow in the Marombas River, Brazil

ABSTRACT Water erosion is influenced by climate, soil, soil cover and soil conservation practices. These factors can be modified by natural (especially climate) and/or anthropogenic (especially soil, soil cover and conservation practices) actions. The relief factor also influences the water erosion and can also be partially modified by anthropic action. This study aimed to evaluate the impact of anthropogenic action due to the introduction of soil crop in no-tillage system on water erosion, and on the consequent flow of sediments in the water. The study was carried out in the Marombas river basin with an area of 3,939 km², using the Soil Water Assessment Tools (SWAT) model. The calibration and validation of the model for sediment production was carried out with a historical series of synthetic data. The data from this series were estimated by linear regression from sediment value load and the average daily flow obtained punctually in the basin’s outlet. The SWAT model was calibrated on a daily scale with data from 1979 to 1989 and was validated with data from 1994 and 1997. The SWAT model was suitable to represent the average daily flow and sediment flow in the Marombas watershed. The hypothesis of reduced sediment production with increasing soil crop in no-tillage system was accepted.

Assessment of soil erosion hazard and its mapping using GIS technologies

The article presents a method for creating a territory erosion hazard integrated map using RUSLE integral model, Earth remote sensing data and GIS technologies. The studies carried out on this topic are presented, the analysis of which has shown a more active use of integral indicators of water-erosion processes in foreign scientific works. Urgency of updating methodology for studying erosion processes has been substantiated. Theoretical foundations of the application of integral models of soil erosion are given, the application of the RUSLE model is substantiated, and the optimal way of using this model is proposed. The research methodology has been developed, consisting of primary processing of remote sensing data, calculation of the factors of erosion development and creation of a territory erosion hazard integrated map. Based on the processing of aerial photography materials, a point cloud, a digital elevation model and an orthomosaic map of the study area were created. The results of the geoinformation analysis of the remote sensing data, which included calculation of the soil erodibility factor and the topographic factor, are presented. Based on the integral indicator of watererosion hazard, a complex map of the erosion hazard of the territory has been created. Main patterns of geographical distribution of the values of the integral indicator of the water-erosion hazard of the territory are revealed, devised methodology is assessed. It was found that the schematic map reflects the general pattern of water erosion processes: they are more active in places where more dissected relief is spread. Influence of the soil factor on the pattern of the schematic map is shown: the pattern in the territories occupied by sod-podzolic loamy soils qualitatively differs from the pattern on the lands where sod-podzolic sandy loam soils are widespread. Patterns on the schematic map of different parts of the developed linear forms of relief, formed by temporary streams, are described. It is shown that the proposed method can be used to assess the water-erosion hazard of the territory. The need to take into account a larger number of factors and to refine the assessment of existing ones is concluded.

Cartographic analysis of the distribution of degraded lands (on the example of the Рoltava region)

Cartographic analysis can be considered as one of the means of the land monitoringsystem, in particular, by the distribution of degradation processes. The work is proposed to createfor regions of cartogram of total distribution of degraded agricultural land and cartograms offraction of agricultural lands that have undergone water and wind erosion, acidification, salinization,with indispensable drawing on these cartograms of the river network scheme. The zoning of the Poltava region is presented and analyzed in terms of the total distribution ofdegraded agricultural land, as well as separately by the particles of water, wind erosion,acidification, salinization.According to the relative distribution of degraded agricultural lands (without taking intoaccount the overlap of various types of degradation) within the Poltava region, there are 2 groups ofdistricts of increased land degradation: 1) northern (covers 7 districts – Pyriatyn, Chornukhy, Lubny,Lokhvytsia, Myrhorod, Hadiach, Zinkiv) and 2) southeastern (covers 3 districts – Kobeliaky, NoviSanzhary and Mashivka).Water erosion is inherent in districts with significant difference in heights and largest forestcover. This is primarily Dykanka, Zinkiv, Reshetylivka districts (watershed between rivers of Psel andVorskla), Lokhvytsia and Chornukhy districts (watershed between rivers of Sula and Udai) and theChutove district (watershed between rivers of Vorskla and Orel). Wind erosion covers predominantlynorthwestern, north and southeastern districts – Pyriatyn, Chornukhy, Hrebinka, Lokhvytsia,Hadiach, Mashivka, Novi Sanzhary.Cartograms of distribution of degraded land are supplemented by the river network on them.The method of their creation is described. The cartographic method is substantiated by theinterconnection of the districts of increased acidification of soils with basins of the rivers Udai andVorskla, and the districts of minimum acidification of soils – with the basin of the river Khorol.Salinization of soils of the Poltava region should be associated, obviously not with superficial,and with groundwater. In the future, it is recommended to use for a cartographic analysis of thedistribution of degraded lands additionally maps of groundwater hydroisogyps.

Monitoring of the condition and use of land in settlements (on the example of the city of Tchaikovsky, Perm Krai)

The paper presents a methodology for monitoring the lands of settlements, analyzes the state of the lands of the city of Tchaikovsky by qualitative and quantitative indicators, evaluates the assessment of the actual state of the lands of the city of Tchaikovsky, and develops a set of measures aimed at the rational use of the lands of the city of Tchaikovsky. The calculations carried out on the level of development and intensity of use of the territory over the past 10 years have allowed us to establish that, over the past 7 years, this indicator has hardly changed in the territory of the city of Tchaikovsky, only 1%. According to the results of a qualitative assessment of the state of the land, it was noted that the humus content in the soils is very low: no more than 3%, in heavy varieties, less than 2% - in light ones. Due to the small capacity of the humus horizon, it is completely involved in the arable layer, so it is reduced on the slopes as a result of water erosion. 35.5% of farmlands with a predominance of a weak degree of water erosion are subject to erosion processes. As a result of the assessment of damage from the manifestation of degradation processes, the amount of 60595 thousand rubles was established. As a result of the landscape and ecological zoning of the city territory, violations of the land use regimes within the boundaries of the established zones were established. Based on the comprehensive analysis, measures have been developed aimed at reducing the negative impact of enterprises and degradation processes. A set of measures to stabilize the state of the lands of the studied settlements is proposed.