RESEARCH OF IRRIGATION QUALITY OF A NEW CENTER-PIVOT SPRINKLING MACHINE

Abstract

The aim of the research was to study the quality of irrigation with a new wide-span center-pivot sprinkler. Material and Methods: the difficulty of optimizing the irrigation technique lies in the fact that the soils of Volgograd region are characterized by great complexity and low water permeability, and the parameters of the rain structure of the sprinkling machines do not always remain constant along the length of the irrigation pipeline. In this regard, the following problems were included in the program of our research: study of the basic parameters of the structure and assessment of the quality of irrigation of center-pivot sprinkler; determination of the horizontal projection width of the rain cloud, the duration of sprinkling, irrigation rate, intensity and rain drops diameter. The soils are loamy, the thickness of the humus horizon is 0.35 m. According to studies of the water-physical properties of soils the irrigation rates for the site selected for irrigation are 450–500 cubic meters per hectare for a half-meter layer and 1000 cubic meters per hectare for a meter-long layer. The average absorption rate for the first hour is 1.7 mm per min, in the subsurface horizon about 1 mm per min. Results: the new sprinkler provides irrigation rates from 200 to 500 cubic meters per hectare with a high uniformity of the distribution of the rain layer along the radius of the irrigated circle. The coefficient of variation of the middle rain layer was set in the range 13.9–19.5 % with an experimental accuracy of 1.2–2.1 at wind speeds of up to 1.5–2.0 m per s. A change in wind speed and direction within 3 m per s does not have a significant effect on the deterioration of the distribution of precipitation (coefficient of effective irrigation = 0.77...0.81). With an increase in wind speed to 5.5 m per s, the coefficient of effective irrigation decreases, but is within the limits of agricultural requirements. Conclusion: the rain intensity, the width of the rain cloud, the time length of the point stay in the rain zone are inconsistent values when irrigated by centre-pivot sprinklers and a certain combination of these parameters is required along the radius of the irrigated circle. The rain cloud of the vehicle has satisfactory wind resistance.

Keywords

• irrigation
• sprinkler
• elements of irrigation technique
• precipitation layer
• rain intensity