Length of molehills for mole irrigation in the lower Volga Region

The studies were carried out in 2022 on the experimental field of the Educational Research and Production Center of the Volgograd State Agrarian University «Gornaya Polyana». The article presents an analysis of the research results of the uniformity of changes in soil moisture at different lengths of sprinklers in the mole irrigation system.

Introduction. Modern irrigation technique must respond the requirements of resource saving and mole irrigation, as a kind of subsoil irrigation, fully possesses these qualities. This method of irrigation does not require large capital expenditures for the construction of an irrigation system in the irrigated area, but at the same time, it can significantly save irrigation water and increase crop yields. In this regard, the study of the features of equipment and technology for irrigation of various agricultural crops by mole irrigation is a perspective direction of our research.

Object. The length of sprinklers in the mole irrigation system.

Materials and methods. The researches were carried out in 2022 on light chestnut soils of the Lower Volga region. One of the main tasks of our studies about the scientific and experimental substantiation of the structural elements of the mole irrigation system was to explore the uniformity of soil moisture at different lengths of mole irrigators. Moisture uniformity was assessed by the dynamics of soil moisture contours on the next day after irrigation in 3 variants of the experiment with molehill lengths of 50, 75 and 100 m in three soil zones: waterlogged soil (˃ 110% of the Lowest moisture capacity), normal (90 ... 110% of the Lowest moisture capacity) and low humidity (75…90% of the Lowest moisture capacity). The observations of the type of the irrigation water distribution in the soil, depending on the length of the mole irrigators, were carried out several times during the irrigation season. This article presents the most typical arrangements of moisture isopleths (lines of the same moisture content) in the soil profile.

Results and conclusions. The results of field experiments showed that when applying the same irrigation rate of 200 m³/ha on the next day after irrigation with an increase in the molehill length from 50 to 100 m, the boundaries of the humidification soil zones did not change their position significantly. The upper boundary of the waterlogged zone remained at a depth of 29…31, normal moisture – 19…20 and low – 6…8 cm, and the lower boundaries - at a depth of 69…72, 85…90 and 105…108 cm, respectively. To the left of the molehill these zones spread by 16...27, 46...51 and 66...73 cm and to the right – by 12...21, 41...42 and 65...69 cm respectively. The mathematical processing of the values of the soil moisture contour area of these zones showed that they did not have significant differences, therefore, the length of the molehill can be increased up to 100 m without a significant deterioration in the uniformity of moisture.

1. Gostishchev D. P. Design, construction and operation of subsoil irrigation systems: Scientific and technical review. M.: Federal State Budget Scientific Institution «Center for Scientific and Technical Information» "Meliovodinform," 2003. 228 p.

2. Gostishchev D. P., Rogozin Yu. S. Use of livestock effluents for mole-soil irrigation // Digest of scientific reports of the international scientific-practical conference «Resource-saving environmentally safe technologies and irrigation equipment». Novocherkassk: "Rainbow," 2004. Pp. 142-145.

3. Acharya S., Mylavarapu R. S. Modeling shallow water table dynamics under subsurface irrigation and drainage // Agricultural water management. 2015. V. 149. Pp. 166-174.

4. Castanheira P. N., Serralheiro R. P. Impact of mole drains on salinity of a vertisoil under irrigation // Biosystems Engineering. 2010. V. 1 (105). Pp. 25-33.

5. Christena E. W., Spoorb G. Improving mole drainage channel stability in irrigated areas // Agricultural water management. 2001. V. 3 (48). Рp. 239-253.

6. Darzi-Naftchali A., Motevali A., Keikha M. The life cycle assessment of subsurface drainage performance under rice-canola cropping system // Agricultural water management. 2022. V. 266. N. 107579.

7. Development of subsurface drainage systems: Discharge – retention – recharge / J. A. Wit, C. J. Ritsema, J. C. Dam, G. A. Eertwegh, R. P. Bartholomeus // Agricultural water management. 2022. V. 269. N. 107677.

8. Effect of controlled drainage on nitrogen losses from controlled irrigation paddy fields through subsurface drainage and ammonia volatilization after fertilization / H. Yupu, Z. Jianyun, Y. Shihong, H. Dalin, X. Junzeng // Agricultural water management. 2019. V. 221. Pp. 231-237.

9. El-Ghannam K., El-sherief A., Nageeb I. The role of Controlled and Mole Drainage in Relation to Water Saving, Salt Accumulation on Sugar Beet Yield and Quality in North Nile Delta // International Journal of Plant & Soil Science. 2021. V. 1 (33). Pp. 47-58.

10. Hydraulic performance of mole drains and validation of steady-state drainage spacing equations for Mollisols / G. F. Camussia, S. Imhoffa, D. L. Antilleb, R. P. Marano // Soil and Tillage Research. 2022. V. 223. No 105448.

11. Lemly A. D. Agriculture and wildlife: ecological implications of subsurface irrigation drainage // Journal of Arid Environments. 1994. V. 2 (28). Рp. 58-94.

12. Numerical simulation of water flow in tile and mole drainage systems / V. Filipovićabc, F. J. Kochem, Y. Coquetc, J. Simunek // Agricultural water management. 2014. V. 146. Рp. 105-114.

13. Rodgersa M., Mulqueenb J., McHalea J. A model study of mole drain spacing and performance // Agricultural water management. 2003. V. 1 (60). Рp. 33-42.

14. Simulating water content, crop yield and nitrate-N loss under free and controlled tile drainage with subsurface irrigation using the DSSAT model / H. L. Liu, J. Y. Yang, C. S. Tan, C. F. Drury, W. D. Reynolds, T. Q. Zhang, Y. L. Bai, J. Jin, P. He, G. Hoogenboom // Agricultural water management. 2011. V. 6 (98). Pp. 1105-1111.