ON THE STUDY OF THE EFFECT OF FERTILIZERS ON CERTAIN AGRICULTURAL CROPS CULTIVATED ON THE TURUNTAEVO PEAT BOG

V. M. Eliseeva, A. Ya. Khromov

Peat soils, consisting of organic substances, are rich in nitrogen and supplied with moisture; at the same time, however, they are, as a rule, poor in potassium and phosphorus. Therefore, in the agricultural use of bogs, phosphorus–potassium fertilization is considered obligatory. Peat soils usually do not require nitrogen. Only in some cases, with weak decomposition of peat in raised and transitional bogs, does a need for nitrogen fertilizers arise [1], [7].

In addition, on bogs, cultivated plants often experience a deficiency of microelements, most commonly copper. Copper starvation in cultivated plants is known under the name “reclamation disease”; it consists in a disturbance of metabolism, leading to abnormal development of plants and sometimes even to their death. The application of copper fertilizer not only eliminates the above-described “disease,” but also makes it possible to obtain high yields of many crops on bogs [3], [5], [6].

The need for fertilizers in different plants on different peat bogs is not the same. In developing a fertilizer system, it is necessary to take into account the requirements of crops for nutrients and the fertility of particular peat soils. To some extent, the fertility of a peat bog can be judged from the chemical and botanical composition of the peat. But it is revealed more fully by experimental means. Therefore, the establishment of field experiments is obligatory; experiments must precede the reclamation of bogs.

We have repeatedly pointed out that, for the first time under the conditions of the taiga zone of Western Siberia, an experiment on studying the effect of fertilizers was established on the Sukhovskoe bog of Bakcharskii District, Tomsk Oblast.

The peat deposit of this bog, 2.5–5 meters thick, is composed of lowland (hypnum) peat, distinguished by high ash content of 22–36% and elevated contents of iron and carbonates. Although the peat of this bog contains much phosphorus, \(P_2O_5\), up to 1% (interlayers of vivianite occur), cultivated plants here need phosphorus first of all, and only against a phosphorus background does the positive effect of potassium become noticeable; nitrogen in the form of ammonium nitrate not only does not improve the yield, but even has a negative effect [2], [3], [4].

Both in the chemical composition of the peat and in the nature of the action of fertilizers, the Sukhovskoe bog is very peculiar. Such bogs are encountered rarely. More often, potassium is in the first minimum. Therefore, it is clar—

...the question of the effect of fertilizers on other bogs under the conditions of the taiga zone of Western Siberia is of interest.

The second experiment on the study of the effect of fertilizers was carried out by us in 1964–1965 near the village of Turuntaevo, Tomsk District, on the Kislov bog, which extends in a narrow strip 250–300 meters wide along the small rivers Chumakla and Tashima, tributaries of the Ya. The bog is separated from the rivers by a levee several tens of meters wide, occupied by willow thickets.

Its peat deposit, 1–2 meters thick, consists of reed–sedge peat, also high-ash (18–25%), with a good degree of decomposition (30–40%) and a pH value of 6.8. In this peat, according to data of the Novosibirsk Agricultural Institute, there is quite a lot of total nitrogen—3.95%, and also a fair amount of phosphorus, \(P_2O_5\)—more than 20 mg per 100 g of air-dry peat (vivianite interlayers occur).

The Turuntaevo (Kislov) peatland was drained in 1958 by open ditches 1.2–1.5 meters deep, which discharged excess water into the adjacent river. The drainage proved sufficient for mechanized cultivation and sowing of crop plants. However, after grubbing and removal of hummocks (with a BDT-2.2 disk harrow), the peatland was used for several years as a natural hayfield, and only in 1963 was oats grown here for green fodder. The low yield of the latter did not indicate high fertility of this peat soil; on the contrary, the rather pale color of the growing plants pointed to a deficiency of some nutrient elements.

The study of the effect of fertilizers on the Turuntaevo peatland was carried out by the Department of Botany of Tomsk State University in cooperation with the Novosibirsk Agricultural Institute in 1965–1966.

In 1965 a field experiment with oats of the variety “Zolotoi dozhd” was laid out according to the scheme \(O\), \(P_{60}\), \(K_{30}\), \(N_{30}\), \(P_{60}K_{30}\), \(P_{60}N_{30}\), \(K_{30}N_{30}\), \(N_{30}P_{60}K_{30}\), Azotobacter, phosphobacteria, cellulose-decomposing bacteria, a mixture of bacteria, where \(O\) is the control without fertilizers; \(P_{60}\) is phosphorus in the form of granulated superphosphate at the rate of \(P_2O_5\)—60 kg per hectare; \(K_{30}\) is potassium in the form of 40% potassium salt (potassium chloride) at the rate of \(K_2O\)—30 kg per hectare; \(N_{30}\) is nitrogen in the form of ammonium nitrate at the rate of \(N\)—30 kg per hectare.

The bacterial fertilizer was applied by treating the seeds with a suspension containing the corresponding variants of microorganisms.

During the growth and development of the plants, differences among the variants were little noticeable; only the plots with complete mineral fertilizer appeared somewhat better and brighter in color. The yield increase relative to the control (Table 1) here amounted to 3.3 c/ha, or 27.4%; the effect of the other combinations was still less significant. Of the bacterial fertilizers, only the mixture of bacteria apparently has a positive effect.

A repeated experiment to determine the effect of fertilizers on the same crop, oats of the variety “Zolotoi dozhd,” in 1966 was laid out according to a modified scheme: control, \(N_{30}P_{90}K_{90}\); \(N_{30}P_{90}K_{90} + \mathrm{Si}\); \(P_{90}K_{90}\); \(P_{90}N_{30}\); \(K_{90}N_{30}\); phosphobacterin, Azotobacter + phosphobacter, Azotobacter + phosphobacter + Si.

The fertilizers were applied in the same form, only with an increase in doses of \(P_2O_5\)—90 kg/ha and \(K_2O\)—90 kg/ha.

The sizes of the experimental plots, as before, remained 100 sq. m, with fourfold replication.

Differences among the variants appeared already at the stage of the third leaf: everywhere potassium had been applied, the plants were ahead in growth and had a broader leaf blade.

The yield data (Table 2), processed by the method of variational statistics, with an error of no more than 2–3%, showed that phosphorus-potassium fertilizers applied in large doses (90 kg/ha) increase the yield of the total mass of oats almost threefold. The application of phosphorus-nitrogen fertilizers without potassium has a negative effect. In the absence of phosphorus, too, a shortfall in yield is observed.

Table 1

Effect of fertilizers on oat yield in the 1965 experiments

Copper fertilizer in the form of CuSO$_4 \cdot$ 5H$_2$O at a dose of 25 kg/ha against the background of complete mineral fertilizer did not show an effect on the oat crop. At the same time, for wheat grown under the same conditions, copper fertilizer was of decisive importance. Without copper its yield was close to zero, whereas wheat fertilized with copper against the NPK background gave a yield of 22 c/ha. From this it may be concluded that on the Turuntaev peat bog, as on the Sukhov peat bog, the “processing disease” is manifested to a strong degree and is eliminated by the application of copper. As is known, oats are less sensitive to copper deficiency [3]; apparently, for this reason the effect of this fertilizer on the oat crop was not noticeable.

The testing of potatoes with various fertilizers was carried out according to the following scheme: control (without fertilizers); N$_{30}$P$_{90}$K$_{120}$; N$_{30}$P$_{90}$K$_{120}$ + polymicrofertilizer, N$_{30}$K$_{120}$; P$_{90}$K$_{120}$, N$_{30}$P$_{90}$. The fertilizers were applied in the same forms, with an even higher dose of K$_2$O — 120 kg/ha. The experiments showed (Table 3) that without fertilizers (in the control) potatoes form a normal vegetative mass, but tubers are not formed. Phosphorus-potassium fertilizers promote tuber formation, increase the resistance of plants to frosts, and make it possible to obtain a yield; however, the size of the latter is small, 69 c/ha, whereas on the Sukhov bog, in farm sowings without any fertilizers, potatoes gave stable yields of 240 c/ha.

Thus, on bogs of the Turuntaev type, where potassium is at the first minimum, the cultivation of potatoes is not advisable.

Under these conditions it is better to cultivate crops that are demanding of nitrogen and less demanding of potassium. The application of phosphorus–potassium fertilizers, with a high supply of nitrogen and regulation of the water–air regime in accordance with the requirements of the crops, will make it possible to obtain high yields of vegetative mass. It must be assumed that such peatlands are most suitable for the cultivation of grasses. This question requires further study.

Table 2

Effect of fertilizers on the yield of oats in the 1966 experiments

Table 3

Effect of fertilizers on the yield of potato tubers
in the 1966 experiments

Thus, the field experiments on the study of the effect of fertilizers on the Turuntaev peatland, in comparison with the previously described experiments on the Sukhov bog, make it possible to draw the following conclusions:

1. The Turuntaev peatland, like the Sukhov peatland, belongs to the type of lowland bogs suitable for agricultural development.

2. The Turuntaev peatland differs from the Sukhov peatland in its position in the relief, the thickness and structure of the deposit, and the botanical and chemical composition of the peat.

3. The effectiveness of phosphorus and potassium fertilizers on these bogs is different: whereas on the Sukhov bog phosphorus proved to be in the first minimum, on the Turuntaev bog it was potassium.

1. In the agricultural reclamation of bogs of both the Sukhovskoye type and the Turuntaevskoye type, phosphorus-potassium fertilizers should be regarded as mandatory.

2. When establishing rates of phosphorus and potassium fertilizers, it is necessary to take into account not only the nutrient requirements of crops, but also the characteristics of each peatland. For bogs of the Turuntaevskoye type, the rates of potassium fertilizers for the same crops should be higher than the rates recommended for the Sukhovskoye bog.

3. In reclaiming lowland-type bogs with a high degree of peat decomposition, the application of nitrogen fertilizers is unnecessary.

4. In selecting the assortment of crops for peatlands, one must take into account their supply of nutrients.

5. On potassium-poor peatlands of the Turuntaevskoye type, cultivation of potatoes is not advisable.

6. The best crops for such bogs will be those that make fuller use of nitrogen and are not so demanding of potassium.

7. The question of the influence of micronutrient fertilizers and bacterial fertilizers on peatlands of the Turuntaevskoye type requires further study.

REFERENCES

1. Agrotechnics of cultivating agricultural crops on peat-bog soils. State Publishing House of Agricultural Literature of the BSSR. Minsk, 1963.

2. V. M. Eliseeva. Experience in the cultivation of bogs of the taiga belt of Western Siberia. Proceedings of TSU, vol. 114. Tomsk, 1951.

3. V. M. Eliseeva. On the question of the causes of the “processing disease” of wheat on peat soil. Proceedings of TSU, vol. 141. Tomsk, 1957.

4. V. M. Eliseeva. On ways of agricultural reclamation of lowland bogs of the taiga zone of Tomsk Oblast. TSU, Tomsk, 1963.

5. M. M. Okuntsov. The physiological significance of copper for plants and its influence on yield. In: Microelements in the Life of Plants and Animals. Publishing House of the Academy of Sciences of the USSR, Moscow, 1952.

6. M. M. Okuntsov, V. M. Eliseeva. Causes of the unproductiveness of certain peat-bog soils of Siberia. Proceedings of TSU, Tomsk, 1948.

7. S. G. Skoropanov. Reclamation and use of peat-bog soils. Publishing House of the Academy of Agricultural Sciences of the BSSR. Minsk, 1961.