Feasibility of stubble biodecomposer application
It is known that the plant residues - stubble, stalks and straw of agricultural crops are an irreplaceable material that replenishes the soil with humus and nutrients for plants and soil microorganisms. The duration of their decomposition is determined mainly by the climatic conditions (humidity and temperature), the amount of crop biomass produced and left on the soil surface. Excessive use of chemicals causes a deficiency of useful microflora, slows down the decomposition of plant residues, promotes the accumulation of lignin, phenols that inhibit the growth of crops and mineralization of soil organic matter, generally worsening the soil condition. As a result, yields are reduced. Therefore, recently, biodestructors of residues remaining after harvesting have been used to improve the soil fertility.
S. Korsun, Doctor of Agricultural Sciences
H. Davydiuk, Candidate of Agricultural Sciences
NSC "Institute of Arable Farming of NAAS"
At the same time, it is assumed that in the case of using a biodestructor, the mineralization of organic matter of both soil and plant residues accelerates, which may lead to lower humus content, unproductive losses of nutrients and additional carbon dioxide extraction from the soil. The task of an efficient biodestructor is to convert plant residues to humus without the "explosive" intensity of mineralization of organic soil substances, as well as to improve its nutrients status.
NSC "Institute of Arable Farming of NAAS" conducted laboratory tests to identify the environmental feasibility of using a biodecomposer. ECOSTERN biodecomposer (manufacturer - PC "BTU-Center") was chosen as the study subject, intended for the decomposition of after-harvesting residues of corn, sunflower and other crops, as well as for treatment of vegetable residues of different origins during composting.
First of all, the question arises: does the biodecomposer generally work on organic residues? Maybe product advertising is just a commercial move?
To determine the activity of ECOSTERN as a biodecomposer a laboratory experiment has been carried out. During the month (30 days) the cellulose plates were kept in contact with the soil treated with ECOSTERN. Control was provided by the soil without treatment with biological products.
The experiment results show that the activity of cellulose destruction in contact with soil treated with ECOSTERN increases twofold - from 25 to 54% (Table 1).
*decomposition level,%
*options
Tabl. 1. Activity of the cellulose destruction with the involvement of ECOSTERN biodecomposer: options of substrates: 1 - soil; 2 - soil + ECOSTERN.
The share of the biodecomposer action on cellulose in option "soil + ECOSTERN" was 53%, and its own soil microflora - 47%.
The next question is: hus, the product efficacy was proven.
The next question is: will the widespread use of ECOSTERN biodecomposer not contribute to increase in carbon dioxide emissions? After all, the problem of increasing concentration of greenhouse gases, including carbon dioxide, in the planet atmosphere is a serious environmental problem nowadays. At the same time, the final product of the decomposition of organic substances in the soil is carbon dioxide, as well as water and other inorganic compounds. Therefore, the intensity of carbon dioxide emissions during composting with the biodecomposer is an important indicator of the environmental feasibility of its use.
The change in the intensity of the respiration of gray forest soil (ie, the release of carbon dioxide) due to its contact with ECOSTERN biodecomposer was determined in a laboratory experiment that assumed a constant temperature (25 °C) and soil moisture.
During 30 days, four substrates were observed emitting carbon dioxide: 1 - soil without addition of bioproducts; 2 - soil + ECOSTERN; 3 - soil + corn stalks; 4 - soil + corn stalks + ECOSTERN.
According to the results obtained, the intensity of respiration in the options "soil" and "soil + ECOSTERN" during the experiment changed in a wide range. The amount of CO2 emissions during composting in the "soil" option was 2.2-109.5, and in "soil + ECOSTERN" option - 2.2-107.8 mg/kg of soil per day (Table 2). The highest values in both cases were obtained in the first three days followed by a smooth decrease. There was no reliable increase in the intensity of respiration in case of ECOSTERN addition to the soil.
In variants "soil + corn stalks", absolute values ranged from 94.1 to 598.9 СО2 mg/kg per day, and in the case of adding a decomposer - 97.4-596.8 СО2 mg/kg of soil per day (Table 3). As in the previous case, a significant difference between option was not found. Maximum values were reached and preserved from the fifth to the eighth day with the subsequent gradual decrease. The analysis of data in Tables 2 and 3 shows that the addition of corn stalks to the soil was significantly more important factor for the increase in respiration intensity than the biodecomposer.
Consequently, the experiment results showed that the action of ECOSTERN biodecomposer created in PC "BTU-Center", stimulating the processes of transformation of organic residues of vegetable origin, did not cause a sharp increase in the release of carbon dioxide into the atmosphere, that is, the product is environmentally friendly. Such an effect was obtained both in composting only the soil, and in composting the soil in a mixture with corn stalks.
* Soil
* Soil+destructor
* intensity of the soil respiration, CO2, mg/kg of soil
* test period
Table. 2. Change in the intensity of the gray forest soil reparation under the influence of ECOSTERN biodecomposer in a laboratory experiment.
Table 3. Change in the intensity of the gray forest soil reparation with the addition of corn stalks and ECOSTERN biodecomposer in a laboratory experiment.
One more important question remains: is soil humus not lost due to the acceleration of mineralization processes under ECOSTERN influence? To answer this question, after completing the respiration experiment, which lasted for 30 days, the content of total humus and carbon labile organic compounds in the soil was determined.
According to the analysis results the soil treated with the decomposer showed no humus loss, but showed a weak tendency to increase the total humus (Table 4). Obviously, such an effect is due to the transformation by existing ECOSTERN organisms of small and partially destroyed plant residues that were present in the soil. The content of labile organic compounds that are the first reserve of nutrient elements for plants remained almost constant in the humus.
* Soil+straw
* Soil+straw+destructor
* intensity of the soil respiration, CO2, mg/kg of soil
* test period
* –value of carbon content of labile organic compounds increased by 10 times
Table 4. Content of humus substances in substrates after composting with ECOSTERN biodecomposer: 1 - soil; 2 - soil + ECOSTERN; 3 - soil + corn stalks; 4 - soil + corn stalks + ECOSTERN.
When composting of the mixture of soil and corn stalks, the amount of humus substances practically did not change from the use of the decomposer. Obviously, the decomposer action in this case was aimed at the mineralization of large plant residues and the duration of the action of the destructive organisms was insufficient for the formation of humus substances. This is confirmed by a clear tendency to increase in the labile organic compounds in the humus. When composting For composting with a decomposer, their number increased by 9.7% (relative), compared with the option without a decomposer.
It is important to note that, despite the clear tendency to change in the organic matter of the soil under the biodecomposer influence, composting the soil with corn stalks has had a more positive effect and provided a growth of total humus by 26% (relative) and carbon labile organic substances by 68% (relative), compared with the option without corn stalks.
Example of ECOSTERN biodecomposer use in in Chernihiv region, 2017
The results obtained in the laboratory setting were verified at in Chernihiv region on typical chernozem. Treatment of after-harvesting residues and shredded stems of the precursor (corn) by ECOSTERN biodecomposer in a dose of 1.5 l/ha, in combination with UAN at a dose of 40 kg/ha (control - 100 kg/ha UAN) in corn crops, increased the yield of Pioneer 9911 hybrid by 9.7 c/ha. The application of ECOSTERN biodecomposer at a dose of 1.5 l/ha, in combination with UAN at a dose of 80 kg/ha (control - 80 kg/ha UAN) in corn crops, increased the yield of the same hybrid by 11.4 c/ha.
Table 5 - Effect of ECOSTERN biodecomposer on corn crop yield, in Chernihiv region, 2017 Pioneer 9911 corn hybrid
|
No. |
Option |
Yield, c/ha |
Increase, c/ha |
|
1 |
UAN 100 kg (control) |
118,9 |
– |
|
UAN 40 kg + ECOSTERN, 1,5 l/ha |
128,6 |
9,7 |
|
|
2 |
UAN 80 kg (control) |
110,7 |
– |
|
UAN 80 kg + ECOSTERN, 1,5 l/ha |
122,1 |
11,4 |
|
|
|
НСР 05 |
2,365 |
|
Thus, the results of the yields obtained at in Chernihiv region are confirmed the laboratory studies that application of ECOSTERN product contributes to the decomposition of organic plant residues, improvement of soil and accelerates the release of essential nutrients needed by plants that have been linked to the organic matter of byproducts. That is, under the influence of ECOSTERN biodecomposer, the conditions of corn nutrition were improved, which contributed to the increase in yields.
Laboratory tests conducted and their verification in the production conditions prove the feasibility of using ECOSTERN biodecomposer in agriculture (manufacturer PC "BTU-Center").
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