Proceedings of the Tomsk Order of the Red Banner of Labor Polytechnic Institute named after S. M. Kirov

Volume 178
1969

LAYER-BY-LAYER MILLING METHOD FOR THE PRODUCTION OF PEAT-MINERAL-AMMONIA FERTILIZERS AND THEIR EFFECTIVENESS UNDER THE SOIL AND CLIMATIC CONDITIONS OF THE BELORUSSIAN REPUBLIC

A. V. Tishkovich, A. G. Dubovets, Yu. M. Plotkina, T. D. Prasolova, R. P. Shurygina

One of the simple, economical methods for producing so-called ordinary PMAF, containing 0.5–0.8% nitrogen from ammonia, phosphorus, and potassium, is the layer-by-layer milling method proposed by the All-Union Scientific Research Institute of Peat (VNIITP, Minsk). It is intended for preparing fertilizers both on the sites of peat enterprises and on individual peat bogs and areas scattered among the arable lands of collective and state farms. This method ensures the extraction of peat crumb for fertilizer and bedding of higher quality than the layer-by-layer surface method, since it is based on the technology for producing milled peat.

The machines and mechanisms used in this method are intended to equip the mechanized detachments of district associations of “Selkhoztekhnika,” as well as the specialized farms of collective and state farms.

The technological process consists of four operations: spreading mineral fertilizers over the surface of the peat deposit, milling or loosening the upper layer to the depth of peat removal, turning the peat-mineral mixture in order to accelerate drying, and harvesting the dried layer with the simultaneous addition of ammonia water.

The spreading of mineral potash and phosphate fertilizers is carried out on prepared and drained peat-bog sections by fertilizer seeders ZSTN-2.8 or fertilizer spreaders TUP-3A, 1-PTU-3, RPTU-2, and others. Fertilizer seeders ensure uniform application of mineral fertilizers for one peat removal cycle. When fertilizer spreaders are used, which in their usual form sow large rates of fertilizer per unit area, deeper subsequent disking is required, on the assumption that the peat-mineral mixture will be removed over several cycles. In this case, the uniformity of mixing of mineral fertilizers with peat will be somewhat lower than in the first case.

At present, the Bobruiskselmash plant is beginning serial production of the removable device RKM-500 with the TUP-3A trailer-spreader, intended for surface application of mineral fertilizers. This device will make it possible to use trailer-spreaders more successfully for spreading mineral fertilizers over the peat bog for each peat harvesting cycle. In addition, taking into account the possibility of using trailer-spreaders for hauling peat and PMAF during and after the end of the peat-extraction season, equipping district detachments with them...

...associations of “Sel’khoztekhnika” should be considered more advisable than with fertilizer seeders. Operation of the 3SNT-2.8 fertilizer seeder is carried out by incorporating and doubling the sections (successive coupling of sections) in a trailer to a Belarus or DT-54, 55 tractor. In this case, potash fertilizers are loaded into one section, and phosphorite meal into the other two, which ensures the simultaneous application of two components in one pass of the machine without their preliminary mixing.

The application rate of mineral fertilizers—potash \(Q_k\) and phosphorite \(Q_p\)—per unit area is determined by the amount of peat \(P\) harvested from this area by the peat-harvesting windrower in one or several cycles (when mineral fertilizers are spread by trailer spreaders without the use of a special attachment).

\[ Q_k = P \cdot m_k,\ \text{kg}, \tag{1} \]

\[ Q_p = P \cdot m_p,\ \text{kg}, \tag{2} \]

where \(m_k\) and \(m_p\) are the application rates of potash and phosphate fertilizers per ton of peat of 50% moisture content, in kg.

The amount of peat harvested from a unit area (net) is determined by the formula:

\[ p = \alpha \cdot a \cdot h \cdot \gamma, \tag{3} \]

where
\(h\) — thickness of the harvested layer, m;
\(\gamma\) — bulk density of peat, t/m\(^3\);
\(\alpha\) — collection coefficient;
\(a\) — area of harvested peat, m\(^2\).

The application rates of ammonia water, phosphate, and potash fertilizers per 1 ton of peat of 50% moisture content are determined by the current technical specifications for PMAF (MRTU 46 No. 313, 1962).

If the harvesting moisture content differs from the calculated value (equal to 50%), then in formulas (1) and (2), instead of \(P\), it is necessary to substitute the value of the peat weight \(P_1\), obtained by recalculation according to the formula:

\[ P_1 = \frac{P(100 - W)}{100 - W_1}, \tag{4} \]

where \(W\) is the calculated moisture content of the peat,
\(W_1\) is the harvesting moisture content of the peat.

Milling or loosening of the peat deposit is carried out with SBF-2 milling drums. The milling depth is 15–20 mm. Milling is performed according to a circular pattern on two-shift fields. In the case of work on marginal plots that do not have a regular field network, milling is carried out with consideration of the area and configuration of the plot according to the pattern most rational under the given specific conditions.

The milled peat crumb, mixed with mineral components, is dried to a moisture content of 50–55%. For this purpose, depending on weather conditions, one or two harrowings are performed, carried out with VMF-type harrows. Harrowing is performed according to circular or zigzag patterns. For harrowing, wheeled tractors or crawler tractors are used, the same as those used for milling. During harrowing of the peat crumb, it is necessary to ensure that the machines used do not additionally undercut the peat deposit, which would prolong drying time and worsen the operating conditions of the machines during harvesting of the dried peat.

Harvesting of the peat-mineral mixture and its enrichment with ammonia water are carried out by peat-harvesting windrowers T-4 or BU-55,

equipped with AP-2 ammonia feeders, designed by VNIIT. Peat-harvesting windrowers have copying devices proposed by VNIIT, which ensure removal of a layer of peat crumb of a specified thickness (within 1.5–3.5 mm) and moisture content (within 40–60%). Peat-harvesting windrowers with ammonia feeders are mounted on DT-55 tractors.

The AP-2 ammonia feeder is a mounted device and consists of a supply system, a pumping unit, and a distributing device. The supply system includes two tanks and a feed tank. The tanks, with a total capacity of 700 liters, are connected to each other by a pipeline, mounted on brackets at the rear of the tractor, and equipped with a water-level glass and valves: a breather valve and an air valve. A sealed feed tank with a capacity of 180 liters is fastened to the blade of the windrower and is equipped with a water-level glass, a breather valve, and an equalizing tube. The feed tank is connected to the tanks by a pipeline having a tap controlled from the tractor cab. The feed tank serves to maintain constant head at the moment ammonia water is introduced into the peat.

The pumping unit is intended for filling the tanks with ammonia water and includes a vortex pump driven by the hydraulic pump (NSh-40), operating as a hydraulic motor from the tractor hydraulic system; a delivery hose connected to the left tank; and a corrugated suction hose with a mesh filter and a check valve.

The distributing device is intended for the uniform introduction of ammonia water into the peat layer being harvested and includes four hoses connecting the feed tank to a distributing pipe 48 cm in diameter, in which nipples with calibrated openings are installed every 100 mm. Rubber hoses are fitted onto the nipples of the distributing pipe, through which the ammonia water enters the peat. Metal tubes 100 mm long, serving as counterweights, are inserted into the free ends of the hoses. The distributing pipe is located in front of the shaft windrower and is hinged to its side walls by means of a frame.

Raising and lowering of the frame is carried out by a hydraulic cylinder (TsS-75) installed behind the blade by means of a two-arm lever. Lowering of the distributing pipe, which determines the application rate of ammonia water, is regulated by a limiting chain, which is pre-calibrated. When the pipe is lowered into the working position (down), the hoses, with their free ends, lie on the surface of the deposit. The supply system operates on the principle of gravity feed of ammonia water from the feed tank into the distributing pipe and then through the hoses onto the peat layer being harvested. The consumption of ammonia water is regulated by changing the head created by the column of liquid enclosed between the lower end of the equalizing tube and the distributing pipe. The amount of liquid in the tank in this case does not affect its flow through the distributing pipe. The application rates of ammonia water are indicated on the side wall of the blade. The supply and cessation of the outflow of ammonia water are carried out by a valveless method, by lowering or raising the distributing pipe below or above the end of the equalizing tube.

The peat-harvesting windrower with the AP-2 ammonia feeder operates according to a shuttle scheme: the forward pass is the working pass, the reverse pass is idle. The operating scheme of the harvesting windrower, depending on the configuration of the plot and the presence of a field-card network, will vary. On plots with a standard field-card network (card width 40 m, length 500 m), it is more rational to locate the storage unit of finished product...

along the strip ditch. In this case the working passes of the windrower are made at an angle of 40–45° to the strip ditch.

When working on marginal or small isolated areas and peatlands that do not have a regular strip network, the storage of the finished product is carried out on the basis of the specific conditions. In these cases, when the windrower is operated, an indispensable requirement is that the locations of the storage units be brought as close as possible to the margins, in order to improve the conditions for hauling out the fertilizers at any time of year.

Table 1

Technical characteristics of the AP-2

The operation of the windrower with the AP-2 differs hardly at all from its usual operation in harvesting peat crumb. Before work begins, the skids of the moldboard copying device are set to the specified depth of peat-crumb harvesting. The link of the front suspension of the moldboard is fastened to the cylinder and the moldboard with the outer pins (the middle pin is removed), which makes it possible to provide their hinged connection, or the so-called free suspension of the moldboard, by means of the gap formed between the link and the rigid stop of the moldboard. In this case the rod of the hydraulic cylinder for lifting the moldboard must be extended outward to the maximum amount.

At the beginning of the plot, the tractor operator, by means of the hydraulics, lowers the moldboard onto the ground, moves the distribution pipe into the working position, and starts moving; in this process the ammonia water flows by gravity into the peat crumb being harvested. At the end of the working pass, before the peat is delivered into the windrow, the distribution pipe and the moldboard are raised into the transport position, automatically stopping the inflow of ammonia water. After this, the tractor backs up to the beginning of the plot and the work cycle is repeated. When the ammonia water from the feed tank has been used up, it is filled while the tractor is moving during the nonworking pass; for this purpose the tractor operator, from the driver’s seat, opens the valve on the pipeline of the reserve reservoirs. After the feed tank has been filled (the tractor operator monitors this by the water-level gauge glass), the valve is closed.

The peat-harvesting windrower with the AP-2 performs the following operations: collecting peat crumb, introducing ammonia water with simultaneous-

…its mixing with peat and the formation of stockpile units up to a height of 3–3.5 m.

The productivity of TMAU preparation per unit area, as is known, is determined by the set of machines required for this technology and by the availability of the necessary number of tractors. An approximate calculation of the need for machines, taking into account their two-shift operation on plots of 50–60 ha, is given in Table 3.

Table 2

Production and technical indicators of peat extraction for fertilizer and bedding and of TMAU preparation

Table 3

Machines for the production of TMAU

In individual cases, when there are very small areas of the peatlands being developed and a small production plan for peat for fertilizer or TMAU, each technological operation may be represented by one machine. In this case, the tractor on which the AP-2 ammonia feeder is mounted can be used for the sequential performance of all TMAU production operations according to this technology. Naturally, in this case the productivity of the work will be reduced.

In 1962 the AP-2 ammonia feeder successfully underwent state tests at the Western Machine-Testing Station and was recommended for introduction. Since that same year, the layer-by-layer milling method for producing peat-mineral-ammonia fertilizers has been used at the peat enterprises “Znamya Sovetov” and “Chervenskoye” in Minsk Oblast.

Production experience shows that PMAF prepared by the layer-by-layer milling method have small ammonia losses, a lower cost, and lower labor expenditures in comparison with the preparation of such fertilizers by other schemes. Table 4 gives the cost of PMAF prepared in Minsk Oblast in 1962–64 by various methods.

Table 4

Cost of one ton of PMAF (moisture—55%), prepared by various methods

The conditions for servicing the windrower with the AP-2 ammonia feeder during work on the preparation of PMAF are entirely satisfactory. No special protective equipment, apart from that provided for by the instructions on the rules for using ammonia water in agriculture, is required.

Five years of work by the All-Union Scientific Research Institute of Peat (VNIIT) confirm a significant yield-increasing effect both from peat and from the mineral fertilizers included in peat-mineral-ammonia fertilizers, or so-called PMAF. Experiments to test the effectiveness of PMAF were conducted at the “Dukora” peat experimental station and on collective farms in the Pukhovichi District of Minsk Oblast. The soils are soddy, strongly and moderately podzolized, sandy loams, underlain by moraine loam or sand. They contain few nutrients, have high acidity and a low degree of base saturation ($P_2O_5$—4.5 mg per 100 g; $K_2O$—3 mg per 100 g; humus 2%; pH in KCl—4.4; $S$—2.1–3.5 mg-eq; $V$—30–50%).

Table 5 presents five-year yield data for various crops under peat-mineral-ammonia fertilizers, under equivalent amounts of the active ingredients of mineral fertilizers and peat included in PMAF, and under pure mineral fertilizers.

Field experiments were conducted in accordance with the methodology of experimental work. The experiments were replicated four and five times. The experimental data by treatments were processed by the method of analysis of variance. The accuracy of the experiments presented in the table is within the limits of reliability.

The data presented convincingly show the considerable advantage of PMAF over separately applied components included in their composition, and also in comparison with an equivalent amount of mineral fertilizers. At the same time, the latter two treatments are almost equivalent in their effectiveness. This means that peat applied to the soil without preliminary treatment with ammonia gives almost no effect in the first year. In individual cases, where under grain crops were applied—

Table 5

Effectiveness of PMAF in comparison with other fertilizers

strongly acid peat was applied, there was even some reduction in yield (experiments 4 and 5 for 1962). This same peat, treated with ammonia and composted with mineral fertilizers, when applied to the soil as part of PMAF, gives, as is evident from the data of experiments 4 and 5, a yield increase equal to 4.3–5 centners per hectare.

Peat-mineral fertilizers have a strong aftereffect. For example, barley sown after potatoes under which PMAF had been applied gives a yield 4.5–4.7 c/ha higher than from the aftereffect of an equivalent amount of complete mineral fertilizers.

The more modest yield increases from PMAF in comparison with NPK in two experiments in 1965 are explained by the fact that PMAF had been applied to the equalizing crops of the two preceding years on these plots. Since these fertilizers have a strong aftereffect, soil fertility and the yield of subsequent crops increase, and the difference between the increases from PMAF and NPK is leveled out.

The average yield increases over 5 years from PMAF in comparison with NPK amount to 2.5–3 c/ha for cereals and 35–30 c/ha for potatoes. PMAF also provide a high yield increase for sugar beet and corn. Economic calculations show that, when the hauling distance for fertilizers is 5 km, each hectare of potato plantings fertilized with PMAF gives 178 rubles more increase than an equivalent quantity of mineral fertilizers. When the hauling distance for fertilizers is increased to 25 km, PMAF also give a higher profit than NPK. The economic efficiency of PMAF is somewhat lower than that of mineral fertilizers when they are applied to cereal crops, which is explained by the lower purchase prices for grain. But even in this case, if the grain increase from the aftereffect of PMAF is taken into account, their economic effect is higher than that of mineral fertilizers.

As our studies have shown, the effectiveness of PMAF is largely determined by the high mobility of the elements of mineral nutrition contained in them. Experimental data show that, in soils after the application of PMAF, the mobility of nutrients is higher than in soils to which mineral fertilizers are applied in pure form: for phosphorus by 1.2 times, for nitrogen by 2.2 times, and for potassium by 7.3 times. In addition, after the application of PMAF the moisture capacity of soils increases by approximately 25%. These data explain the reasons for the stable effectiveness of PMAF under both favorable and unfavorable climatic conditions, especially in dry years. Above all, such fertilizers contribute to a significant improvement in the water-physical properties of soils. On the other hand, the high mobility of nutrients ensures the constant presence (even when there is a lack of moisture in the soil) of complete mineral nutrition in the zone of development of the plant root system.

Many years of research by the institute have definitively confirmed that all types of peat—lowland, transitional, and raised-bog—of medium and high degrees of decomposition are suitable for the production of PMAF. At the same time, the effectiveness of fertilizers prepared on raised-bog peat is not inferior to the action of fertilizers prepared on lowland peat. In some respects, raised-bog peat has an advantage over lowland peat. It absorbs two and a half times more ammonia and, being more acidic, promotes to a greater extent the conversion of calcium phosphates of phosphorite meal into mobile compounds of phosphoric acid. As a result, inexpensive phosphorite meal as part of PMAF is not inferior in its action to the more costly phosphate. The high absorptive capacity of raised-bog peat makes it possible to prepare, on its basis, fertilizers with an ammonia content increased by 1.5–2 times. In addition, fertilizers based on raised-bog peat have

significantly lower ammonia losses during production and especially during use.

The investigations carried out in this part show that, when fertilizers are spread over the soil surface, as the peat dries, losses occur of ammonia present in aqueous solution. Such ammonia, as has been established, may account in PMAF for up to 30% of the total amount absorbed. Five hours after the spreading of PMAF prepared on upland peat, they may lose up to 6–7% of ammonia, whereas PMAF containing lowland peat lose 2–3 times more ammonia. In this connection, when PMAF are applied to the soil they must, without delay, be incorporated with disk harrows or other implements to a depth of 8–12 cm. Unfortunately, in practice this is often neglected, which leads to large losses of ammonia and a sharp reduction in the effectiveness of the fertilizers.

The effectiveness of PMAF depends to a large extent on the duration and timing of their storage. When PMAF are stored in the autumn–winter period (from October to February–March), ammonia losses are insignificant—2–5%; in the spring–summer periods they increase to 13–18%. At the same time, the acidity of the fertilizer medium gradually increases. Therefore, PMAF prepared in winter and stored through the spring should be used first of all for sowings of early cereals, sugar beet, early potatoes, and other crops. Fertilizers produced in spring should preferably be used for maize, later crops, and potatoes, while those produced in summer should be used for sowing winter crops. PMAF prepared in autumn may be left in storage for use in the spring of the following year.

Thus, provided that PMAF are produced in accordance with the technical requirements for them, and provided that the agrochemical standards for their storage and use are observed, they are highly effective, economically advantageous fertilizers. However, contradictory judgments are sometimes encountered regarding the assessment of the effectiveness of PMAF as organo-mineral fertilizers. The principal reason for this is that the production of such fertilizers is not always of good quality. Considerable deviations are allowed in the uniformity of the content of mineral components in the fertilizers, along with large production losses of ammonia. In using PMAF, unjustifiably long-distance transportation is often resorted to, causing higher costs; incorrect and untimely incorporation into the soil, as noted above, leads to additional substantial losses of ammonia. All this will inevitably reduce the quality of the fertilizers and their effectiveness.

LITERATURE

1. L. A. Khristeva. Physiological function of humic acids in the processes of metabolism in higher plants. In: Humic Fertilizers, the Theory and Practice of Their Application. Kharkov State University Press, 1957.

2. S. Guminskii. Mechanism and conditions of the physiological action of humus substances on the plant organism. Soil Science, No. 12, 1957.

3. A. V. Tishkovich. Theoretical and technological substantiation of the production of peat-mineral fertilizers. In: Production and Application of Peat-Based Fertilizers. Minsk, 1963.

4. A. V. Tishkovich et al. Production and application of peat-ammonia fertilizers. Industry of Belorussia, No. 4, 1964.