Assessment of ecological efficiency of the scheme ofagrolandscape formation at the level: system of gullendrainage areas gullen drainage area of the Aidar River

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Assessment of ecological efficiency of the scheme of agro landscape formation at the level: system of gullen drainage areas gullen drainage area of the Aidar River

Belolipskyi V., Poluliakh M., National Research Center «Institute of soil science and agrochemistry named after O.N. Sokolovsky»

Goal. To assess ecological efficiency of the scheme of formation of agrolandscapes at the level: system of gullen drainage areas ^ gullen drainage areas of the Aidar river. Methods. Laboratory-field, mathematical-statistical, topometric, morphological. Results. The basic erosionecological situation of the object of research is determined. PS levels are calculated for the Steppe zone. An Integral map of soil erosion hazard classes of the Steppes of Ukraine is constructed. At the level of the system of gullen drainage areas of the Aidar River, the analysis is carried out of the nature of the impact of forecast and actual erosion-hydrological indicators (runoff costs) on the development of erosion-hydrological processes on a probabilistic basis (1; 5; 10; 50%) by their ratio.

On the example of the Yevsuh and Kovsuh river basins, plowing indicators are calculated for key drainage areas along the river with differentiation of administrative land use. The map of the structure of the Yevsug and Kovsug river basins within the drainage areas is constructed. The structure of sown areas and their plowing is assessed according to the potential runoff indicator: up to 5 mm -- insignificant, 5.1 - 8 -- weak, 8.1 - 15 mm -- moderate, with erosion index levels (3 and lower; 3 - 4; 4 - 5; 5 and above) and grouping the structure of sown areas. According to the simplex method, the analysis of actual and forecast erosion-hydrological indicators and optimization of the structure of sown areas is carried out. For the Aidar River basin the model structure of crop rotations is obtained. Ecological assessment of the structure of crop rotations is performed according to the coefficient of ecological danger of crop rotations.

Conclusions. At the level of the gullen drainage areas system, the coefficient of the ratio of KV of forecast and actual losses of the river runoff as an indicator of the development of erosion- hydrological processes on a probabilistic basis (1; 5; 10; 50%) at hydro-posts along the Aidar River showed that at 10% security in case of reduction of plowed lands to 50 - 60%, a high level of runoff reduction (81 - 90%) was observed at the Bakhmutivka hydro-post, medium (73 - 85%) -- at Bilolutsk and Starobilsk hydro-posts, the lowest -- at the Kuriachivka hydro-post (39 - 65%). The study of humus content in the range of 4.5 - 5.5% by groups of arable land areas 40 - 60% revealed constant decrease in Qmax (average maximum runoff losses) in the range of 8 - 9%. At the level of individual gullen drainage areas, the determination of the basic erosion-ecological situation of the object of research on the integrated map of erosion hazard classes of steppe soils of Ukraine showed its belonging to the class of moderate erosion hazard with runoff of 8.1 - 15.0 mm.

Key words: basin, drainage areas, hydro-post, slopes, humus, runoff, costs, factors, coefficient.

The main goal of creating a unified system for managing water resources in the basin is to optimize water use and increase the number of used water resources in the basin by applying a unified basin approach that combines territorial and administrative interests. The essence of the ecosystem-basin approach to water resources management is to shift the focus from the water bodies themselves to the entire basin and to systems of girder catchments and individual girder reservoirs in agricultural landscapes in order to fully cover all possible causes of environmental violations, intersectoral and inter-territorial contradictions and to prevent and eliminate negative phenomena [1-7].

Basins are the most objective natural basis for solving many problems in the field of rational natural science [8, 9]. The effectiveness and duration of the system of catchment channels depends on their compliance with the landscape and environmental conditions of the territory [10-12].

In Ukraine, at the regional level and within the entire territory of basin structures, practically targeted development of small and medium-sized rivers is not carried out. The water strategy for minimizing erosion processes in agricultural landscapes is based on research conducted in the Aidar river basin [13, 14], it was used for soil and water management of agricultural landscapes at a new information level [15, 16].

Objects and methods of research

The goal is to assess the environmental efficiency of the agro-landscape formation scheme at the level of: system of girder catchments girder reservoirs R. Aidar. Object - soil and water protection arrangement of agricultural landscapes on a basin basis. Subject - ecological efficiency of the scheme of formation of agroland-shaftiv at the level of: system of beam catchments beam reservoirs of Aidar. The place of geographical research beyond the question is the Aidar river basin on the territory of Troitskiy, Novopskovskiy, Bilokurakinskiy, Markivskiy, Starobilskiy and Novoaydarskiy districts of Luhansk region; additions, testing, development and analysis of experimental material were performed for the catchments of the Evsug and Kovsug rivers on the territory of Novoaydarskiy, Starobilskiy, Belovodskiy, Stanychno-Luhansk districts.

Research problem

1) Determination of ecological efficiency of application of schemes of formation of agricultural landscapes on catchments.

2) Develop anti-erosion measures taking into account the erosion indices of land safety in the system of girder catchments, confined to the Aidar river hydro stations.

3) Develop anti-erosion measures at the level of beam catchments based on the analysis of the ratio of the structure of acreage and potential runoff.

Research methods

To achieve the research goal in the context of the tasks set, the following methodological approaches are used.

1. Indicators of storm costs in modern economic activities are characterized by maximum rainfall floods of small rivers and quantified models medium maximum discharges of the river flow (Q_Max) with different probability of exceedance (10, 25, 50%) - the term "cost of river runoff" is used in the system: the small river's basin-system water-beamed - beamed catchment [13].

Management of the maximum flow of rain floods of the river (with the exception of the flow rate of the river) is carried out by geoinformation modeling of erosion processes on the basis of erosion indices of land safety in the system of girder catchments, confined to the hydroposts of the small river basin [13].

2. To determine the nature of the interaction of forecast (acceptable) and actual parameters for the development of erosion and hydrological processes in order to minimize them on a probabilistic basis (10, 25, 50%) with the corresponding parameters of flow rates, the coefficient of their ratio Ctr is calculated (formula 1).

(1)

3. Geoinformation modeling of erosion processes in the Evsug and Kovsug river basins, taking into account the structure of acreage on a basin basis.

To model erosion processes as an indicator of the intensity of erosion-hydrological processes (situations), the erosion index of land Availability (Ei) of various Availability levels is used: as a ratio of Qmax 10...50 % probability of exceeding the flow rate to the average value of the statistical series of observations Qmax 50 % probability by formu

(2)

where Q-i-50% - average maximum flow costs 1-50% probability, Q50% - average maximum flow costs 50% probability, m³/s [13].

4. Ecological efficiency of application of the scheme of formation of agro-landscapes on beam catchments.

The problem is solved using the linear programming method (simplex method), in which the target function and main variables are selected, as well as a system of constraints that should give a fairly complete subject-specific characteristic of erosion and hydrological processes. The ecological efficiency of the scheme of forming the agrolandscape at 2 levels (system of girder catchments ^ girder reservoirs) is considered.

At the first level, the optimality criterion is the coefficient of the ratio of actual and acceptable indicators of average-maximum flow rates (Ctr).

At the second level, the optimality criterion is the requirement to increase the potential runoff to an environmentally acceptable level - 5 mm (PR / EAL) [10] with the model structure of acreage.

Results and discussion

At the system level of beam catchments to complete the ecological assessment of the ecological efficiency of the scheme for the formation of agricultural landscapes, an analysis of the nature of interaction between forecast and actual erosion and hydrological indicators (flow costs in small rivers) for the development of erosion and hydrological processes based on probability theory was carried out (1, 5, 10, 50%) by calculating the coefficient of their ratio Ctr according to the formula 1 according to the average-maximum flow rates of the corresponding probability, m3 / s [13].

Models of average-maximum flow costs of 10,25,50% of Availability are calculated based on the system dependence (formula 3):

(3)

where А10, 25, 50% is the coefficient for probabilities: A-m%=8,79 * 10^-13, A25%=1,14 * 10^-14, A50%=4,0 * 10-18;

F - percentage of the catchment area within the key area;

X - storm precipitation, mm; fn - devastation, %; Ssl - slopes > 1, %;

Fhum - humus content, %; Sgbn - gully-beam network, %;

Sft - the first terrace of the river, %; Stfb - transverse forest belts, %

Spl - plateau (slopes up to 1⁰), %.

Model adequacy indicators: multiple correlation coefficient: R = 0,904, relative error of model E=2,17%.

The value of the Ctr coefficient characterizes the degree of decrease in the flow rate values in the case of reduced ploughing of catchment lands (table 1).

Table 1. The ratio Qforecast /Qfact of different provision of hydroposts in the catchment area of the river Aidar

With 10% availability of flow expenditure in the case of a decrease in the water catchment land area to the level of 50-60% , the highest level of flow reduction (81-90%) was observed at the Bakhmutivka hydropost, the average (73-85%) at the Bilolutsk and Starobilsk hydroposts, and the lowest - at the Kuryachivka hydropost (39-65%).

According to the hydro stations along the Aidar river (Bilolutsk ^ Starobilsk ^ Bakhmutivka) in the upper and middle parts, almost the same ratio of forecast and actual indicators of flow costs and its change in the lower part (Bakhmutivka) was found. Separately, this relatively high ratio is allocated to the Kuryachivka hidropost catchment, since it is a self-independent catchment of the Belaya river with a coefficient of ravines Kr = 0.95 km/km² (in comparison: Bilolutsk - 0,75, Starobilsk - 0,81, Bakhmutivka - 0,88 km/km²).

Studies of humus content in the range of 4.5-5.5% for groups of arable land areas of 4060% revealed a constant decrease in Qmax in the range of 8-9%. Therefore, the detailed minimization of the erosion-hydrological process should be considered when developing a set of antierosion measures in the agricultural block of the agro-landscape for groups of eroded soils.

In the block of ecological interrelations of acceptable indicators of combinations of components of the agrolandscape, the areas of transverse forest belts (0,3-0,5%) contribute to a slight decrease in Qmax by dependence (Stfb^-0'⁰²²) - formula 3.

At the level of individual beam catchments the analysis of the ratio of the structure of acreage and potential runoff is performed in accordance with the following methodological principles:

Assessment of the erosion-hydrological and ecological situation in the agricultural landscapes of the beam catchments.

In solving this issue, it is necessary to proceed from the need to determine the main erosion and environmental conditions of the studied objects. This allows to form both scientifically substantiated general schemes of soil and water protection measures, and to create functional models of agrolandscape as a foundation for elementary design.

(4)

where R - is the erosion index of rain of 10% availability;

X_a - weighted average slope steepness by region;

Ха - weighted average coefficient of the flow-regulating role of the agrofone of the corresponding structure of sown areas by districts;

Kgc - flow-regulating role of ground cover;

Клєм - flow-regulating role of reclamation (anti-erosion) measures.

Fig. 1

The value of the PR is determined for each administrative district and, in accordance with the classification, zoning is carried out by regions of the Ukrainian Steppe territory, followed by drawing up an integral map of classes according to the degree of manifestation of potential runoff (Fig. 1). the map Scheme is the starting point for determining the directions of reliable protection of soil cover.

Probabilistic quantitative assessment of PR allows us to determine the degree of potential danger in modern agroecosystems under certain natural conditions, and is the basis for forecasting and designing soil protection measures.

The object of our research is located in the South-East of Ukraine and is characterized by a PR indicator within the range of 8 -15 mm.

The legend of the integrated map looks like this (table 2).

On a basin basis, anti-erosion measures in agricultural landscapes should be implemented dynamically and differentially, taking into account the erosion and hydrological situation. Strategy program implementation protarsi development of agricultural landscapes is based on the change in cropping patterns (that is, the changes in the project scope of land use and increase storehouse the role of soil fertility) and includes the following steps:

Table 2. Indicators and their normalization for the integrated map of erosion and hydrological zoning of the Steppe of Ukraine [10]

Stage 1. Calculations of weighted average ploughing indicators on a basin basis with analysis of the structure of the river basin. The example of the Evsug and Kovsug river basins shows the differentiation of administrative land use corresponding to key catchment areas along the river (Fig. 2, table 3). the Methodological approach used to determine the ploughing of the territory does not contradict the basin principle, because it considers the issue of determining the weighted average ploughing in the structure of the Entire Evsug and Kovsug river basins with the differentiation of administrative land use in the catchment areas of rivers.

Fig. 2. The structure of the basin of the river Evsug and Kosug within catchment areas