Phosphorous balance in different fertilization systems in agrocenosis of the Central Forest-Steppe

Note: * Coef. V,% - coefficient of variation; *** max-min - amplitude range; **** L 0.75- L 0.25 - quartile scope or normalized scope.

The average median stock of P2O5 in the total phytomass of the organic fertilizer system was lower by 1.20 and 1.35 times relative to the organo-mineral fertilizer system. The interval and typical range of P2O5 stock was narrower relative to the organo-mineral fertilizer system, and Coef * v were in the range of 8.9712.5%, which indicates the stabilization of the process of P2O5 accumulation in the structural elements of phytomass. The main products accounted for 69-70% of P2O5 from the accumulated stock in the total phytomass. According to the organo-mineral fertilizer system, the average phosphorus yield for all articles was 90.5 kg/ha with an amplitude range Amax-min = 5.6 kg/ha. The median yield was at the level of the average value (91.0 kg/ha), and the typical interval range was AL0.75-0.25 = 2.4 kg/ha, which indicates a stabilization in time of P2O5 entry into the balance circulation of phosphorus in crop rotation.

The income of P2O5 due to the lateral, aboveground and root phytomass was 17-18% of the total income of both average and median values and amounted to 15.6-16.3 kg/ha. The value of the receipt of P2O5 for this article by the median tended to the upper typical value, which indicates a growing trend of a positive article P2O5.

The balance of P2O5 on the average and median values was positive at the level of + 17.4-17.5 kg/ha. The interval and typical scope were narrowed, which indicates the stability of the P2O5 balance in crop rotation under the organo-mineral fertilizer system. The balance capacity of the organo-mineral fertilizer system was 164-165 kg/ha, and the interval amplitude and normalized range of values was Amax-min = 16.0 kg/ha and AL0.75-0.25 = 9.0 kg/ha. The coefficient of variation was at the level of Coef * v = 3.82%, which indicates the stability of the balance capacity over the years of research. The turnover rate of P2O5, which was determined by the ratio of P2O5 content in the total biomass to the consumption of P2O5 during the growing season (B), was <1.0, which indicates a high level of circulation. Amplitude and normalized interval values of P2O5 turnover rate were Amax-min = 0.13 kg/ha and AL0.75-0.25 = 0.05 kg/ha, which indicates the intensive circulation of P2O5 at low values of Coef * v <10,0. The values of the balance intensity (IBsr = 0.5) significantly exceeded 100%, which confirms the conclusion about the high level of P2O5 circulation in the agrocenosis of short-rotation crop rotation during 8 years of research (Table 3).

Under the organic fertilization system, the yield of P2O5 on all balance sheet items was 6.5 times lower than the average value and 7.2 times lower than the median value. The amplitude range was 4.4 kg/ha at absolute values of deviation of 7.2-7.3 times less compared to the control variant. Receipt of P2O5 was provided by the content of P2O5 in by-products. The removal of P2O5 by the main products was 2.39-2.45 times lower. The limits of the interval range and the limits of the typical values of P2O5 removal were 2.162.67 and 2.30-2.45 times smaller compared to the organo-mineral fertilizer system, which affected the level of P2O5 balance, which was negative and was characterized by the intensity of the balance Ib <100% and did not exceed 50%. The balance capacity under the organic fertilizer system was 3.46-3.82 times lower, as well as the interval amplitude and normalized typical values. The turnover rate of P2O5 was 1.94-2.05 times lower, and the value of B was higher than one: B>1.33-1.45, which indicates a low intensity of circulation of P2O5 in the agrocenosis of short-rotation crop rotation under the organic fertilizer system (table 3).

The evaluation of the balance of different models of fertilizer systems in short-rotation crop rotation was performed on the set of paired correlations between the set of features in the matrix correlation field. In the general model of the correlation matrix of paired correlation coefficients (n=54), direct and inverse correlations (R>0.50) account for 39% of interactions. Of these, 39% are direct strong correlations, 27.8% are inverse strong correlations, and the ratio between them is 2.5 to 1 in favor of functional (direct) connections, and the connections that stabilize the system (inverse) account for 11, 1%. There were 61% of the total number of functionally insignificant connections (± R <0.50).

In the organo-mineral system, the fertilization of strong bonds (± R> 0.5) was 44%. Of these, 37% - functional connections, 7.4% - stabilizing, inverse, and the ratio of functional and stabilizing connections was 5 to 1. Relationships insignificant (± R <0.5) were 55.6%. In the conditions of the organic system, the fertilization of functional bonds as a whole was 52%; direct action - 35.2%; reverse action - 16.7% at a ratio of 2.1 to 1. Non-essential connections as in the previous case was 48.2%.

According to the fertilizer model, the yield of k.o. and the balance capacity P2O5 correlate at the level of direct strong correlation (R = 0.87-0.96 ± 0.02; R2 = 0.76-0.92), and per unit of output growth k. and the main products account for an increase in the capacity of the balance of P2O5 7.63-10.7 kg. In this case, the speed of rotation P2O5 and crop rotation productivity at the output of k.o. and the main product correlates with each other at the level of weak correlation.

It is established that a direct correlation is established between the P2O5 balance capacity and the output of the main product in 5-field grain-row crop rotation according to the general model at the level of strong correlation, and the unit of phosphorus balance capacity growth is 0.008 t/ha of the main product yield.

4. The regression equation between the capacity of the balance of phosphorus, nitrogen and the yield of the main product in the grain-row 5-row crop rotation under different fertilizer systems

The capacity of the phosphorus balance determines the yield of the main product by 64%. There is a direct correlation between the capacity of the phosphorus and nitrogen balance at the level of strong correlation, and the unit of growth of the phosphorus balance is the increase of the nitrogen balance capacity by 1.15 units (Table 4).

The organo-mineral fertilizer system also shows a direct correlation between the phosphorus balance capacity and the yield of the main product at the level of strong correlation, and 0.08 units of the output of the main product per unit growth of the balance capacity. The capacity of the phosphorus balance determines the yield of the main product by 90%. A direct strong correlation was found between the phosphorus-nitrogen balance capacity, and 6.03 units of nitrogen per unit of phosphorus growth capacity growth (Table 3).

Fig. 1. Dynamics of yield of winter wheat and spring barley depending on the fertilizer in the grain- row 5-field crop rotation for 2011-2019