Agrogenic changes in the redox potential in the profile of light-grey forest surface gleyed soils of the Western Forest-Steppe

Ukraine

Abstract

From this it follows that long rotation, plowing of organic residues (stubble, II clover meadow) on the control without fertilizer application leads to the development of genetic horizons. OB processes (Table 2). The pH kci indicator in the control experienced subsequent changes, where it amounted to 4.22, 4.18; 4.31; 4.13 units respectively (confidence interval (average) X± SX - 4.27 with an error of 0.04). Low- oxidation conditions (446 mV) at pHkci 4.22-4.47 were observed in the illuvial (446 mV) and transitional to rock (440 mV) horizons. In strongly illuvial gleyic parent rock (PIgl) ORP was at the level of 437 mV. From this it follows that long-term crop rotation, ploughing of organic residues (stubble, 2nd mow of meadow clover) on the control without use of fertilizers leads to the development of weakly oxidizing redox processes in the soil genetic horizons (table. 2). crop deferrization soil fertilizer acidic

2. Change of redox potential in the profile of light gray forest surface-gleyed soil depending on various anthropogenic pressures, 2015-. 2017 years

Note. X+Sx - confidence interval (mean) for 95% probability; Sx - standart error; V ,% - coefficient of variation (index of variability of a numerical series); S - standard deviation.

More contrasting change in the ORP was observed in the profile of light gray forested surface-gleyed soil compared to the control (var. 1) in the organo-mineral fertilizer system with the background of liming with a full dose of CaCO3 according to Ha (var. 12). Increased value of redox potential to 628 mV in the HEglarable horizon indicates the development of intensively oxidizing processes (table. 1). In HEglsubsoil and Ehgl horizons, oxidation/reduction processes according to Clark indicators 29.3 and 27.1 were characterized as moderately oxidizing. In the Iegl horizon (51 cm depth) Eh potential difference dramatically changed from weakly oxidizing (420 mV) to weakly reductive processes in lower-lying Igl and IPgl genetics horizons, 388 - 370 mV respectively. The lowest boundary of the weakly reductive redox-mode (363 mV) and Clark's index (20.2) under such fertilizer system was observed in the highly illuvial and the highly gleyic parent rock (PIGl) at 4.05 pHkci. Attention should be paid to the increased (13.1 %) coefficient of variation (V) of the soil pH in 12th variant. It indicates a wide range of changes in the reaction of the soil solution (from 5.15 to 4.05) and its relation to the redox potential in profile (table. 2).

Studies have shown that long-term use in the experiment mineral fertilizers alone in a dose of N65P68K68 (var. 15) contributed to a decrease in ORP in the direction of reduction processes in the profile compared to the control without fertilizers and the organo-mineral fertilizer system. Highest ORP values were obtained in the humus-eluvial arable (0-22 cm) and sub-arable (23-35 cm) layers: 426 and 416 mV respectively. In underlying horizons ORP decreased from 398 mV to 318 mV at pHkci 4.17 -4.04, which characterizes the processes occurring in them as weakly reducing and close to moderately reducing, and remained so up to PIGl (311 mV) (Table 2). Subsequently, under such conditions, on acidic light gray forest surface-gleyed soils, a decrease in the redox potential will cause an excessive accumulation of plant toxic compounds Fe2+, Mn2+, Al3+ [15], which will lead to even more acidification of the soil and adversely affect the nutrition of the plants, which will ultimately reduce the crop yield in crop rotation.

Conclusions

Thus, the use of an acidic light gray forest surface-glowing soil of the organo-mineral fertilizer system at a dose of N105P101K101 + 10 t / ha of manure + CaCO3 (1.0 Ha) creates the best conditions for the formation of intensively oxidative processes. Prolonged plowing of soil without fertilizer application (control) leads to the development in the profile of weakly oxidized processes. The systematic application of mineral fertilizers (N65P68K68) into the soil as compared to the control and organo-mineral fertilizer system contributes to a significant reduction of the redox potential in the direction of recovery processes. For substantiation of optimum doses of fertilizers and lime and ensuring balanced natural cycles of the circulation of substances of acidic light gray forest surface-charred soils at different levels of agricultural load, it is advisable to use as a highly sensitive estimation indicator a redox potential soil from its natural equilibrium.

References

1. Natsionalna dopovid pro stan navkolyshnoho pryrodnoho seredovyshcha v Ukraini u 1999 rotsi Ministerstva ekolohii ta pryrodnykh resursiv Ukrainy. (2000) [National Report on the State of the Environment in Ukraine in 1999 by the Ministry of Ecology and Natural Resources of Ukraine]. Kyiv: Rajewski Publishing House. [In Ukrainian]

2. Husson, O. (2013). Redox potential (Eh) and pH as drivers of soil/plant/microorganism systems: A transdisciplinary overview pointing to integrative opportunities for agronomy. Plant Soil, 362, 389-417.

3. Simek, M., & Cooper, J. E. (2002). The influence of soil pH on denitrification: progress towards the understanding of this interaction over the last 50 years. Eur. J. Soil. Sci., 53, 345-354.

4. Truskavetskyi, R. S., Zubkovska, V. V., & Khyzhniak, I. M. (2015). Rol hidromorfizmu v rodiuchosti gruntiv [The role of hydromorphism in soil fertility] Foothill and mountain agriculture and stockbreeding, 58 (1), 199-211. [In Ukrainian]

5. Mamontov, V. G. (2006). Obshchee pochvovedenie [General Soil Science]. Moskva: Kolos. [In Russian]

6. Hopkins, W. G., & Huner, N. P. (2009). Introduction to Plant Physiology (4th ed.). New York: John Wiley & Sons, Inc.

7. Seo, D. C., & DeLaune, R. D. (2010). Effect of redox conditions on bacterial and fungal biomass and carbon dioxide production in Louisiana coastal swamp forest sediment. Science Total. Environment, 408, 3623-3631.

8. Greenberg, R. C. (1998). Understanding the redox (rH2) measurement of the biological terrain: Part I. Biomed Therap., 16, 156-158.

9. Fiedler, S., Vepraskas, M. J., & Richardson, J. L. (2007). Soil redox potential: Importance, field measurements, and observations. Adv Agron, 94, 1-54.

10. DSTU ISO 11271: 2004. Yakist gruntu. Vyznachennia okysno-vidnovnoho potentsialu. Polovyi metod. Chynnyi vid 01. 05. 2006. [National Standards of Ukraine ISO 11271: 2004. Soil quality. Determination of redox potential. Field method. Effective from 05/05/2006]. Kyiv: State Consumer Standard of Ukraine. [In Ukrainian]

11. Cheshko, N. F., & Tsapko, Yu. L. Patent no. 50067 Ukraine, МРК G01N 33/24. Sposib potentsiometrychnoho vymiriuvannia okysno-vidnovnoho potentsialu v grunti [Method for potentiometric measurement of redox potential in soil]; no. u2009 11887; stated 25.05.2010. 6 p. [In Ukrainian]

12. Dmitriev, Ye. A. (1972). Matematicheskaya statistika v pochvovedenii [Mathematical statistics in soil science]. Moscow: Izd-vo MGU. [In Russian]

13. Dospekhov, B. A. (1985). Metodika polevogo opyta (s osnovami statisticheskoy obrabotki rezultatov issledovaniy) [The methodology of field experience (with the basics of statistical processing of research results)]. (5th ed.). Moscow. [In Russian]

14. Khtryan, N. K. (1976). Osnovnye zadachi i obshchie metody izucheniya pochvennogo rezhima. [Main tasks and general methods of studying the soil regime]. Proceedings of the Research Institute of Soil Science and Agrochemistry of the Ministry of Agriculture. Armenian SSR, 1, 28-34. [In Russian]

15. Kyrylchuk, A. A., & Bonishko, O. S. (2011). Khimiia gruntiv. Osnovy teorii i praktykum: navch. posib. [Soil chemistry. Fundamentals of Theory and Workshop: Tutorial]. Lviv: Ivan Franko National University. [In Ukrainian]

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