REPORT

Formulation Development for the Organo-mineral Fertilizer on the Peat-Sapropel Basis and Check of Its Efficiency

Abstract

The report contains 16 pages, 4 tables, 6 figures, and reference list.

Key words: peat, sapropel, mineral fertilizers, organo-mineral mixture, dummy experiments.

Work objective: development of the organo-mineral fertilizer on the basis of peat and sapropel.

Rationale: To provide plants with elements of mineral nutrition, to preserve and reproduce soil fertility, to create sustainable agriculture, it is necessary to use fertilizers. Unilateral use of only mineral or organic fertilizers does not solve this problem completely.

In this connection, the use of all-purpose fertilizers containing both organic and mineral components becomes relevant. Amidst the lack of traditional organic fertilizers, considerable reserves of peat and sapropels in our country can serve as cheap raw materials of natural origin to prepare organic mineral fertilizers.

Fertilizer mixtures, combining the advantages of mineral and organic fertilizers, containing, in addition to main macroelements (nitrogen, phosphorus and potassium), microelements, humic and biologically active substances, have comprehensive impact on soil fertility, growth and development of plants.

1. Methodological Foundation of Development

Multiple agrochemical studies have shown that different types and forms of fertilizers have unequal impact on soil properties. The fertilizers added to soil enter into complex interactions with it and their impact on soil fertility depends on the nature of these interactions. The use of mineral fertilizers alone leads to degradation of topsoil - soil acidity increases, humus losses increase as a result of its mineralization, the soil structure and protective functions of soil degrade.

Sapropels represent a valuable natural resource for current and future use in agriculture as fertilizers increasing soil fertility.

Sapropels include fine-structure colloidal deposits of freshwater reservoirs with organic matter content of at least 15% and ash content of 20 to 60%. The main components of sapropel ash are silicon oxide, calcium carbonate, magnesium, iron, aluminum, manganese, phosphorus, sodium oxides. Sapropel has high water-retaining and low filtration capacity. When interacting with soil, due to its adhesive ability, the sapropel improves the soil structure, provides it with lumpiness, looseness, increases air permeability. The composition and structure of sapropels makes it possible to use them for reproduction of soil fertility, especially on degraded soils and light granulometric soils. The main reasons for relatively low efficiency of sapropels are their insufficient nutritional value. Their nitrogenous substances are mainly represented by high-molecular compounds strongly bound to humic substances inaccessible for plant nutrition. The content of available phosphorus is very low, and potassium content is negligible, which leads to the necessity to add very high doses of fertilizer when it is used in pure form.

Different types of peat have high organic matter content (in the sample presented - 73%), but the efficiency of its use is limited to long period of its mineralization. The peat has few soluble forms of nitrogen and accessible organic matters. In addition, the use of high doses of peat leads to an increase in soil acidity. Therefore, the use of pure peat for fertilizing is inefficient and economically unreasonable. Sapropels contain an acid-alkali buffer system, which prevents soil acidification. Joint application of peat and sapropel will ensure the flow of organic matter into the soil, retention of favorable soil pH for cultivation of agricultural plants, and, due to silty fractions in the sapropel, will ensure formation of organo-mineral complexes promoting the fixation of humic substances in soil.

Samples of peat and sapropel provided for the analysis and assessment of the possibility to make a fertilizer mixture on their basis have low nutrient content and, when mixed, can achieve values required by GOST NY 525-2011 (weight content of the total amount of nitrogen, phosphorus and potassium is not less than 5%, weight content of organic matters is not less than 45%) only on the organic matter. According to TU 9841-001-0066732-93, the standard content in fertilizing amendments should not be less than: N - 2.5-3%, P2O5-1.5-2%, K2O-1.0-1.5 %, organic matter 45-50%. To optimize the total nutrient content, it is necessary to add a relevant amount of mineral fertilizers to the mixture. The proposed composition of the mixture is made up taking into account the nutrition elements contained in provided samples and the content of N, P2O5 and K2O in certain fertilizers.



The control sample of the mixture was prepared under laboratory conditions by thorough agitation of all components. Mineral fertilizers were pounded with a pestle and added to the mixture of peat and sapropel.

The developed fertilizing amendment was analyzed in the Test Center for Soil and Environmental Studies. The results of laboratory studies (from protocol No. 167/2 of December 07, 2012) of the mixture composition are shown in Table 1.

Table 1.Results of fertilizing mixture composition analysis.

Identifiable parameters	Measurement units	Results of studies	Test method
??	pH unit	6.7
Organic substance (losses on ignition)	%	57.6
Humic acids (to organic substance)	%	71.59	According to Kononova-Belchikova
Fulvic acids (to organic substance)	%	17.05
Humins (to organic substance)	%	11.36
Total phosphorus	%	1.573
Total potassium	%	2.101
Total nitrogen	%	2.53
Cation exchange capacity	mmol/3.5 oz (100g)	39.3

The developed mixture complies with the requirements of specifications, necessary declared parameters (TU 9841-001-0066732-93) and is a highly concentrated organo-mineral fertilizer of long-term action.

2. Dummy Greenhouse Experiments

The purpose of dummy greenhouse experiments was to obtain preliminary assessment of the efficiency of the mixture as an organo-mineral fertilizer. The test culture was barley (Hordeum L.).

Dummy greenhouse experiments were carried out on sod-podzolic sandy loam soil (pH-7.2, K20- 65 ppm, P2O5- 165 ppm, humic content 1.04%) in plastic vessels with a volume of 1 pt, the fertilizer was added upon vessel packing.


Fig. 1. Experiment Layout.

Plants were grown under conditions of natural photoperiod, illumination and temperature in the laboratory. The sowing was made using sprouted seeds to a depth of 0.5 in. There were three replications of the experiment. Vessels were placed randomly in 2 rows. To equalize the conditions of illumination during the vegetation period, the vessels with plants were regularly repositioned.

Watering was carried out by weight to a humidity corresponding to 70% of the field moisture capacity. During the vegetation period, observations of the growth and development of plants were made. Harvesting was performed 18 days after emergence of seedings. The roots of plants were washed and dried. After drying, the herbage and roots were weighed.

Dummy experiment 1.

Time frame: November 9-27, 2012.

Experiment goal: Obtaining preliminary assessment of efficiency of the fertilizing amendment (FA) depending on the degree of grinding of sapropel and the application method.

During dummy experiment 1, two application methods of fertilizer mixture were studied - the basic application and the surface application. The fertilizer efficiency was compared depending on the degree of grinding of the sapropel - granular and powdery form. The experimental design was supplemented with a variant with preliminary treatment of sapropel, included in the fertilizer mixture with 3% solution of H2O2 (at the ratio of 10:1).

Experimental design:
Variant 1. Control - no treatment soil
Variant 2. FA t 10 - fertilizing amendment with granulated sapropel treated with hydrogen peroxide, application dose - 10,000 ppm of soil.
Variant 3. FA g 10 - fertilizing amendment with granulated sapropel, application dose - 10,000 ppm of soil.
Variant 4.FA p 10 - fertilizing amendment with powdered sapropel, application dose - 10,000 ppm of soil.
Variant 5.FA sur.4 - surface application of fertilizing amendment with granulated sapropel, application dose - 4,000 ppm of soil.
Variant 8.Sg 40 g - granulated sapropel, application dose - 40,000 ppm of soil.
Variant 9.Sg 40 g+fer - granulated sapropel, application dose 40,000 ppm of soil + mineral fertilizers in a dose corresponding to 0.3 oz of FA/2.2 ft of soil.
Variant 10.Sp 40 g - powdered sapropel, application dose - 40,000 ppm of soil.
Variant 11.Sp 40 g+fer - powdered sapropel, application dose 40,000 ppm of soil + mineral fertilizers in a dose corresponding to 0.3 oz of FA/2.2 ft of soil.



Fig. 2. Barley sprouts, 1-5 variants of experiment.


Fig. 3. Barley plants, variant 1 - control and variant 5 - with surface application of FA.

At the emergence stage, a high dose of fertilizing amendment caused a slight lag in the growth of barley, which is accounted for by the exposure of the unformed roots of the seedlings to a high concentration of mineral fertilizers. The inhibitory effect was leveled at further stages of plants development.

The barley sprouts in the variant with surface application of FA are significantly ahead of the plant development with no treatment. This pattern persists until the control harvesting. The fifth variant of the dummy experiment 1 showed the maximum increase.


Fig. 4. Barley sprouts in dummy experiment 1, variants 1, 8-11


Table 2. The results of dummy experiment 1.

Variant	Tops		Roots
	Weight, gr	% to no treatment	Weight, gr	% to no treatment
1. No treatment	0.81	0	1.05	0
2. FA t 10	1.05	30	1.21	14
3. FA g 10	1.02	27	1.08	2.4
4. FA p 10	1.06	31	1.07	1.5
5. FA sur.4	1.3	60	1.29	21
8.Sg 40 g	0.91	12	1.24	17
9.Sg 40 g+fer	1.01	24	1.05	0
10.Sp 40 g	0.7	-13	0.91	-14
11. Sp 40 g+fer	0.97	20	1.08	1.9
???0.05	0.15

The application of the fertilizing amendment led to a significant increase in the weight of the seedlings. To test the effectiveness of a lower dose of FA, taking into account the greatest increase in variant 5 and the inhibitory effect on plant growth at the seedling stage, dummy experiment 2 was designed and carried out.

Dummy experiment 2.

Time frame: November 20 - December 10, 2012.

Experiment goal: Obtaining preliminary assessment of efficiency of the fertilizing amendment (FA) depending on the degree of grinding of sapropel and the application rate.

Experimental design:

Variant 1. Control - no treatment soil
Variant 2. FA t 4 - fertilizing amendment with granulated sapropel treated with hydrogen peroxide, application dose - 4,000 ppm of soil.
Variant 3. FA g 4 - fertilizing amendment with granulated sapropel, application dose - 4,000 ppm of soil.
Variant 4.FA p 4 - fertilizing amendment with powdered sapropel, application dose - 4,000 ppm of soil.
Variant 5. FA g 2 - fertilizing amendment with granulated sapropel, application dose - 2,000 ppm of soil.



Fig. 5. 7-days barley sprouts in variants of dummy experiment 2.

In all variants with FA application, the growth of plants is outstripping in comparison with the no treatment variant. This pattern persists till the end of the experiment.


Fig. 6. Barley sprouts in variants of dummy experiment 2.

The results of dummy experiment 2 are shown in Table 3.

Table 3. The results of dummy experiment 2.

Variant	Tops		Roots
	Weight, gr	% to no treatment	Weight, gr	% to no treatment
1. No treatment	0.79	0	1.18	0
2. FA t 4	1.12	42	1.21	2.6
3. FA sg 4	1.14	44	1.12	-4.7
4. FA sp 4	1.31	66	1.35	14
5. FA 2	0.96	21	1.06	-10
???0.05	0.14

3. Discussion of the Results of Dummy Vegetation Experiments and Recommendations

The preliminary results of the studies showed a high fertilizing ability of the peat and sapropelbased organo-mineral mixture. The use of the mixture favorably affected the looseness and water retention capacity of the soil. When watering plants by weight, the largest losses of moisture were noted in the no treatment variant.

The highest productivity was obtained at lower FA application doses - 4,000 ppm of soil (dummy experience 2 and surface application - experiment 1), which corresponds to a 10 tons/ha application rate. A lower increase in a higher fertilizer dose is due to the inhibitory effect of excess mineral fertilizers. To obtain an increase in yield using only sapropel, very high doses are required.

At a 4,000 ppm FA application dose, the maximum productivity was obtained in the variant with the powder form of sapropel, which is apparently related to the improvement of the water-air regime of the soil.

Sapropel treatment with hydrogen peroxide did not result in a noticeable increase in the weight of the seedlings in comparison with the analogous no treatment variant, which is probably accounted for by a short plants cropping period.

Despite the fact that the barley plants were grown in conditions of insufficient illumination and a short daylight, and, therefore, cannot be considered final and have a provisional character, in all variants using peat and sapropel based FAs, a reliable increase in the weight of the seedlings was obtained in comparison with the no treatment variant, which indicates a high fertilizing ability of the mixture.

It is assumed that the use of the fertilizing amendment will enhance the protective functions of the soil, preventing the entry of heavy metals into plants. Analysis of the root system of barley grown on urban soil contaminated with heavy metals showed a tendency to reduce the content of toxic elements. This can be confirmed by a result of vegetation experiments set for this purpose.

Peat and sapropel based FA is a complete organo-mineral fertilizer. The fertilizer does not contain toxic components and impurities above the permissible values.

The results of the analytical control confirm the compliance of the amendment composition with the regulatory characteristics.

When preparing the amendment under production conditions, it is more expedient to use a completely water-soluble mineral fertilizer, for example, ammophos, and moisten the amendment while stirring to distribute the nutrients evenly.

Conclusion

The stability of the cultivated land, characterized by the ability to preserve the self-regulating functioning of soil fertility reproduction processes, maintenance and increase of the productivity of farmland, prevention of unacceptable degradation changes is provided, first of all, by a scientifically grounded approach to the application of fertilizers.

The unilateral application of mineral fertilizers only replenishes the basic fertilizers gone with agricultural products, and often has a negative effect on soil acidity, results in a depletion of the microelement composition of the soil, and loss of humus. Therefore, recently such interest is shown to organo-mineral mixtures in which the advantages of organic and mineral fertilizers are combined.

The proposed peat and sapropel based FA is a complete organo-mineral fertilizer. The fertilizer has a reaction close to neutral (pH 6.7), contains 57.6% of organic matter, as well as nitrogen (2.5%), phosphorus (1.57%), potassium (2.1%), and microelements. The fertilizer is intended for basic application under agricultural crops. The fertilizer does not contain toxic components and impurities above the permissible values.

The results of the analytical control confirm the compliance of the amendment composition with the regulatory characteristics.

The preliminary results the dummy vegetation experiments showed effectiveness of using a fertilizing amendment with various sapropel forms (granular and powdery) at a dose of 4,000 ppm of soil corresponding to 10 tons/ha.

Application of the fertilizing amendment contributed to improvement of the physical properties of the soil - it increased its looseness and water retention abilities.