SOURCES OF PHOSPHORUS AND THEIR CONTRIBUTION TO ITS RESERVES IN ARABLE SOILS IN THE FOREST-STEPPE ZONE

I. D. Davlyatshin¹, A. A. Lukmanov¹, M. I. Mametov^2
1Center of Agrochemical Service “Tatarsky”, ul. Orenburgskii trakt, 120, Kazan’, 420059, Russian Federation
²Station of Agrochemical Service “Al’met’evskaya”, ul. M. Dzhalilya, 11, Al’met’evsk, Respublika Tatarstan, 423450, Russian Federation

Abstract. An estimation of gross phosphorus content in the main arable soils of the Republic of Tatarstan over 1964–2016 is given. Arable soil horizons contain an average of (0.167 ± 0.06) % of phosphorus (Р2O5), which is the main source of formation of mobile phosphorus reserves in extensive agriculture. In modern intensive agriculture this element, in addition, enters into the composition of organic and mineral fertilizers, including phosphorites. During the period of the investigation, 1078.05 kg of active substances of mineral phosphorus fertilizers were applied per 1 ha of arable land; as well as 430.25 kg of phosphorus went into the soil with 172.1 h/ha of organic fertilizers (the average content of phosphorus in manure is 2.5 kg/t). As part of phosphorites, 9.24 kg/ha of P2O5 were applied. The carry-over of mobile phosphorus with the yield of spring wheat amounted to 1069.2 kg of P2O5, with washed out fine earth – 19.52 kg of P2O5; a consumption for increasing the fertility of the arable horizon (0–20 cm) that existed before 1964, and further deepened by 7.5 cm, is in the amount of 118.91 + 44.59 kg/ha. The difference between the income and expense items indicates a positive balance – 265.33 kg/ha of active substances of P2O5 (annually 5.01 kg/ha or 1.58 mg/kg of soil). Analysis of the calculation of phosphorus balance indicates the need to adjust the research methodology (in particular, the depth of sampling) adopted in the agrochemical service of the Russian Federation. Until 2005, the balance of this element in the agriculture of the republic was positive, which ensured an increase in its content to 145.1 mg/kg; after that the value of this index varied at the level of 130.5–142.2 mg/kg soil. Improved availability of mobile phosphorus affected the yield of spring wheat, which is confirmed by the positive, statistically significant correlation coefficient between the values of these indices. It is equal to 0.53 at the level of significance of 0.01. When using moving averages with a step length of 11 and 22 years, which eliminates the influence of the weather factor, the correlation coefficients increase to 0.75–0.92.

Keywords: sources of phosphorus; content of gross and mobile phosphorus; rocks and minerals; mineral and organic fertilizers; balance; yield of spring wheat; correlation.

Author Details: I. D. Davlyatshin, D. Sc. (Biol.), adviser (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); A. A. Lukmanov, Cand. Sc. (Biol.), director (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.); M. I. Mametov, director (e-mail: Этот адрес электронной почты защищён от спам-ботов. У вас должен быть включен JavaScript для просмотра.).

For citation: Davlyatshin I. D., Lukmanov A. A., Mametov M. I. Sources of Phosphorus and Their Contribution to Its Reserves in Arable Soils in the Forest-Steppe Zone. Dostizheniya nauki i tekhniki APK. 2018. Vol. 32. No. 4. Pp. 21-24 (in Russ.). DOI: 10.24411/0235-2451-2018-10404.