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Section 10. Agricultural sciences
В период цветения в слоях почвы с увеличением глубины увеличивается процентное количество фитотоксичных грибов во всех вариантах, кроме пятого.
В конце вегетации различие в количестве токсичных форм бактерий между слоями почвы выражено слабее, хотя тенденция к увеличению содержания таких форм в слое 20-30 см прослеживается, особенно в вариантах 3, 4. В варианте 5 различий между слоями почвы нет, а в 1, 2 — обратная зависимость между глу-
биной взятия образца и слоем фитотоксичных форм бактерий.
Таким образом, состояние микрофлоры под сельскохозяйственными культурами различно. Это зависит от их видового состава, глубины взятия образцов. Однолетние культуры, например ячмень, озимая пшеница, способствуют меньшему развитию различных фитотоксических форм бактерий и грибов.
Список литературы:
1. Берестецкий О. А. Фитотоксины почвенных микроорганизмов и их экологическая роль//Фитотоксические вещества почвенных микроорганизмов. - М.: Агропромиздат,1978.- 203 с.
2. Возняковская Ю. М. Регулирование почвенно-микробиологических процессов в севооборотах интенсивного типа как одно из условий повышения эффективности земледелия. -Труды ВНИИ сельскохозяйственной биологии, 1988. - 58 с.
3. Возняковская Ю. М., и др. Сидеральные удобрения - регулятор почвенно-микробиологических процессов в условиях почвоутомления//Доклады ВАСХНИЛ - 1988. - № 2. - С. 95-98.
4. Возняковская Ю. М., Попова Ж. П., Воронова Н. Т. Влияние полевых севооборотов, систем обработки и внесения соломенной резки на биологический режим и плодородие почвы Северного Зауралья.: Труды ВНИИ сельскохозяйственной микробиологии, 1988. - С. 100-105.
5. Гродзинский А. М. Аллелопатия растений и почвоутомление.- К. «Наукова думка», 1991.- 460 с.
6. Кулаков В. А., Балаева О. М., Щербаков М. Ф. Влияние длительного применения минеральных и органических удобрений на продуктивность пастбищных агрофитоценозрв и агрохимические показатели по-чвы//Агрохимия. - 1995. - № 11. - С. 66-75.
7. Куркина В. М. Биологическая активность почвы и формирование урожая озимой пшеницы при различных условиях её выращивания. - Сб. науч. трудов: Пути повышения урожайности сельскохозяйственных культур. - Одесса, 1972. - С. 277-283.
8. Лобков В. Т. Почвенно-биологический фактор в земледелии. -Орёл: НПО «Экология села». -1998. -112 с.
9. Лобков В. Т. Почвоутомление при выращивании полевых культур. -М.: Колос, 1994. -112 с.
10. Мишустин Е. Н. Ассоциация почвенных микроорганизмов. - М.: Наука, 1975. - 270 с.
11. Фарниев А. П. Влияние почвенно-климатических условий на интенсивность разложения целлюлозы.: Тез. докл. юбил. науч.-произв. конф., повящ. 75-летию Горс. гос. аграр. ун-та. - Владикавказ, 1993.- С. 34-35.
12. Cutler D.W, Crup L. M., Problems in Soil Microbiology. London 1985.-Р 460.
13. Russel Stefan, Gajewska Julita. Effect ofpeat, urea and NPK fertilization on biological activity of green area soil in Warsaw.//Ann. Warsaw Agr. Univ. - SGGW. Agr. 1995. - № 29. - P.19-25.
Litvishko Valery Semenovich, Russian University of Economics, Moscow Associate Professor, faculty of economics of trade and commodity research
E-mail: [email protected] Myaskovskaya Tatiana, Russian University of Economics, Moscow Senior teacher, faculty of economics of trade and commodity research
E-mail: [email protected]
Reducing toxicity chemicals plant protection products
Abstract: The samples ofmicroencapsulated pesticide have been investigated in acute experiments on laboratory animals. The results of the research have determined that microencapsulation can reduce toxicity of plant protection chemicals. Keywords: microencapsulated form, embryotoxicity, teratogenicity.
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Секция 10. Сельскохозяйственные науки
In the structure of plant protection chemicals controlled release systems ensuring the release of active substances (pesticides, fertilizers, growth regulators, pheromones, etc.) in the environment for a given action according to a prescribed concentration — time program play an important role. In such systems a long-term (prolonged) plant protection chemicals application in quantities below the minimum permissible level of toxic effects on animals and human beings but mortal for plant pests is achieved [1, 165-170].
The variety of controlled release systems are microencapsulated forms based on a polymeric membrane materials [2].
The research to reduce the toxic effects has been carried out on the example ofMetaphos (0,0-dimethyl-0-4-nitrophenyltiophosphate) implementation as the effective means to control cotton pests, legumes pests, tomato pests, fruit trees pests and other crops pests. The samples in a microencapsulated form of the pesticide have been tested in comparison with the emulsion one.
Microencapsulated form was an aqueous suspension of microcapsules with a size of 5-40 microns with wrappers from polikarbomida with an active substance content of 80-90%, emulsion form was an aqueous dispersion of pesticide. Metaphos itself is a widely used pesticide in Russia and abroad. Its toxicological indicators are well studied. The degree of impact on the body according to the classification of harmful substances refers it to the first hazard class (potent toxic substances). It is approved for usage in agriculture as insecticide but due to the high toxicity, embryotoxicity and other negative characteristics associated with adverse effects on mammals, human beings and the environment it is unsound drug.
Toxicity was established when brought into the gastrointestinal tract in male rats weighing 250-300 g. The results are shown in Table 1.
Table 1. - Acute toxicity parameters for white rats
Parameters of toxicity mg/kg Form of Metaphos
Liquid Microcapsulated
DL16 35,0 344,0
О Jr4 О 60,0 365,0
tj- 00 l-l Q 88,0 399,0
Toxicity studies were conducted on adult white mice with body weight 28,2 ±5,0. The clinical picture of intoxication albino rats and mice receiving microencapsulated metaphos was the same type and characterized by the affect on the central nervous system.
The highest mortality rate ofanimals was observed during the first day. Average DL50 microencapsulated Metaphos for white mice after statistical processing of the data was 490,0 mg/kg drug or 122,3 mg/kg active ingredient (ai).
As can be seen microencapsulation has increased by almost an order DL50. This makes it possible to transfer the preparation from the first group of toxicity (according to hygienic qualification — highly toxic) to the third group (moderately toxic).
In determining the irritant properties when applied on skin and mucous membranes of eyes it was revealed that microencapsulated form has moderately severe irritant effect. When applying the drug at concentrations 27,0%, 13,5%, 6,7% and 3,3% (ai) hyperemia disappearing in 1-2 days was observed. Adding 2 drops into the conjunctival sac of rabbits’ eyes caused catarrhal conjunctivitis, disappearing for 4-5 days. Working solutions for treating plants with a concentration of 0,08% by active ingredient do not have the specified effect.
The studies of skin-resorptive action by dipping the mice tails in suspension MK Metaphos showed that the ability of microencapsulated Metaphos to penetrate through intact skin is low. It was found out that a single exposure of microencapsulated Metaphos in concentration by 27,0% ai caused retardation of animals after the experiment and poor flushing of the skin tails that was over in 2 hours.
The application of microencapsulated Metaphos on shaved dorsal rabbit’s skin caused his death during the 1st day at a dose of 163 mg/kg in comparison with 100 mg/kg for nonencapsulated form.
The impact of microencapsulated form Metaphos on reproductive function was evaluated in terms of its embryotoxic and teratogenic characteristics. Investigations were carried out on adult albino rats “Wister”. Rats’ weight was 170-200 grams. The animals were formed into 3 groups. The first group of animals was given Metaphos liquid form (at a dose of 1/8 DL50 -5,5 mg/kg), the second group received microencapsulated form (at a dose of 1/8 DL50-45,6 mg/kg). The third group was a control group. The accuracy of the estrous cycle was determined by vaginal cytologic picture content. Female rats at cycle stage proestrus and estrus were tucked to male rats at ratio of 2:1. The first day of pregnancy was considered a day of onset of sperm in the vaginal contents (the presence of sperm in the vaginal smear). On 18-20 day of rats pregnancy cesarean section was made. At the same time the rule of periodical medical autopsy of animals from
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Section 10. Agricultural sciences
different groups was used. At autopsy the uterine horn and the placenta were observed. The number of corpora lutea, implantation sites and preimplantation death rate, the number of alive and dead foetuses, number of resorptions, total embryonic mortality, foetuses weight and cranio- caudal size were taken into account.
To determine the pathology of internal organs foetuses were microscopically examined being cut into 9 segments. Females of each group were brought to birth, to trace the development of the offspring. In observing the offspring mortality, survival rates and lactation, weight gained in dynamics and sex was taken into consideration.
Monitoring female rats’ pregnancy showed that in the first group of12 animals 4 rats died on 2-5 day after seeding Metaphos. In the same group of 12 rats which were ready to give a birth mortality was also observed after implementation of the drug (4 rats died on 3-7 day of pregnancy). In the second and control groups of rats murrain was not observed. The embryonic material was evaluated after slaughter and dissection of pregnant rats from experimental and control groups. The average number of embryos per female in groups was set as follows: in the first group 6.8 ± 0.6; in the second group 7,9 ± 0,4 and in control one 9,5 ± 0,4. The average embryos weight was respectively: 3,33 ± 1,80 g, the second 4,30 ± 1,30 g in the third 3,70 ± 0,50 g. The average weight of placenta was respectively: 0,67 ± 0,01 g, 0,72 ± 0,20 g, 0,69 ± 0,10 g. Cranio-caudal size (mm) was observed in the first group as 3,56 ± 0,5, in the second group 3,78 ± 0,10 and in control one 3,28 ± 0,20.
Microscopic examination of embryos segmental sections identified no abnormalities in the internal organs. In the first group there was a slow development of the embryo and the appearance ofbrain herniation. In the second and control groups no external malformations were observed. Foetuses had a pink color of skin and showed normal signs of life. Abortions were not noted.
The teratogenicity effect research ofvarious Metaphos forms displayed the following violations of embryonic
development. In the first group one rat was delivered of two and the other of eight dead pups. The rest of the rats of all groups gave birth without complications. The presence of external malformations in rat pups was not found. Any abnormalities in the development of the front of the skull, limbs and abdominal wall (umbilical cord) were not identified. From the first group of animals was obtained 38 pups, the average number per litter was 6,8 ± 0,6 with a range from 3 to 9, the weight difference was from 6,3 to 7,3 g, and cranio- caudal size was from 3,6 to 4,0 mm. The second group of animals obtained 97 pups, the average number per litter was 7,9 ± 0,4 varying from 6 to 11, weight ranged from 4,4 to 8,3 g, and cranio-caudal size was from 3,4 to 4,3 mm.
In the control group were received 114 pups, the average number per litter was 9,5 ± 0,4 with a range from 3 to 12. Weight ranged from 5,2 to 7,7 g, cranio- caudal dimension was from 3,3 to 3,9 mm. Viability of the progeny groups was at the same level. The quantitative ratio of males and females in the first group was: males
3.8 ± 0,5, females 3,0 ± 0,7, in the second, respectively,
4.9 ± 0,5 and 3,0 ± 0,3 and in the control group 5,7 ± 0,4 and 3,8 ± 0,4.
As can be seen from the data in contradiction to nonencapsulated form, microencapsulated form when brought into the stomach of rats causes no teratogenic effect and embryotropic both in ontogeny process and in the postnatal period of their growth and development.
Thus, the samples of microencapsulated metaphos used in acute experiments on laboratory animals indicate that microencapsulation greatly reduces the toxicity of drugs brought in the stomach, local irritant effect on skin and mucous membranes of the eyes and skin-resorptive effect, but it does not affect the reproductive function that has been determined by research of embryotoxicity and teratogenicity. As the result the microencapsulation reduces the danger of intoxication that allows us to transfer metaphos from extremely toxic Group to moderately toxic Group.
References:
1. Litvishko V. S., Microencapsulated Form of Dihloron of the Protracted Selection, Collection of articles based on materials of XVI International scientific-practical conference “Scientific discussion: issues of math, physics, chemistry, biology”, № 4 (16) — Moscow, “International centre of science and education", 2014.- С. 165-170.
2. LitvishkoV. S., Microencapsulated Form of Insecticide prolonged action//Universum: chemistry and biology: electronic scientific journal 2014 г. № 3 (4). URL://http://7universum.com
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