Delovanje atrazina na mikroorganizme u zemljištu

Effects of the herbicide atrazine on soil microorganisms was investigated. Trials were set up in laboratory, on a clay loam soil. Atrazine was applied at 8.0, 40.0 and 80.0 mg/kg soil rates. The abundance of total microorganisms, fungi, actinomycetes, cellulolytic microorganisms and amino-heterotrophs was recorded. Soil samples were collected 1, 7, 14, 21, 30 and 60 days after atrazine treatment for microbiological analyses. The results showed that the intensity of atrazine effect on soil microorganisms depended on treatment rate, exposure time and group of microorganisms. Atrazine had an inhibiting effect on cellulolytic microorganisms and amino-heterotrophs. Initially, it inhibited fungi and actinomycetes but its effect turned into a stimulating one once a population recovered. Atrazine had a stimulating effect on total abundance of microorganisms.U radu je ispitivano delovanje atrazina na mikroorganizme u zemljištu. Ogled je postavljen u laboratorijskim uslovima na zemljištu tipa glinovita ilovača. Atrazin je primenjen u količinama od 8.0, 40.0 i 80.0 mg/kg zemljišta. Praćen je ukupan broj mikroorganizama, broj gljiva, aktinomiceta, celulolitskih mikroorganizama i aminoheterotrofa. Uzorci za mikrobiološke analize uzimani su 1, 7, 14, 21, 30 i 60 dana posle primene atrazina. Dobijeni rezultati su pokazali da delovanje atrazina na zemljišne mikroorganizme zavisi od primenjene količine, dužine delovanja i vrste mikroorganizama. Atrazin je inhibitorno delovao na celulolitske mikroorganizme i aminoheterotrofe. Na aktinimicete i gljive delovao je prvo inhibitorno, a kasnije, zbog obnavljanja populacija stimulativno. Na ukupan broj mikroorganizama atrazin je delovao stimulativno

Pesticidi u zemljištu: delovanje na mikroorganizme

Since their discovery to the present day, pesticides have been an inevitable segment of agricultural production and efforts have been made to synthesize compounds that would share a required efficacy along with selectivity, sufficient persistence on the object of protection and favourable toxicological and ecotoxicological characteristics so as to minimize their effect on the environment. When a pesticide gets into soil after application, it takes part in a number of physical, chemical and biological processes that depend not only on the compound itself, but a number of other factors as well, such as: physical, chemical and biological characteristics of soil; climatic factors, equipment used, method of application, method of storage, handling and disposal of waste, site characteristics (proximity of ground and underground waters, biodiversity and sensitivity of the environment). Microorganisms play an important role in pesticide degradation as they are able to utilize the biogenic elements from those compounds, as well as energy for their physiological processes. On the other hand, pesticides are more or less toxic substances that can have adverse effect on populations of microorganisms and prevent their development, reduce their abundance, deplete their taxonomic complexity and create communities with a lower level of diversity and reduced physiological activity. The article discusses complex interactions between pesticides and microorganisms in soil immediately after application and over the ensuing period. Data on changes in the abundance of some systematic and physiological groups of microorganisms, their microbial biomass and enzymatic activity caused under pesticide activity are discussed as indicators of these processes.Od otkrivanja pa do danas, pesticidi su ezaobilazni seg­ment poljoprivredne proizvodnje, a u njihovom razvoju teži se ka sintezi jedinjenja koja će imati potrebnu efikasnost i selektivnost, dovoljnu dužinu zadržavanja na objektu i povoljne toksikološke i ekotoksikološke karakteristike, kako bi imali što manji neželjeni uticaj na životnu sredinu u celini. Kad se nakon primene nađe u zemljištu, pesticidno jedinjenje biva izloženo brojnim fizičkim, hemijskim i biološkim procesima razgradnje koji zavise ne samo od osobina jedinjenja, već i od čitavog niza drugih faktora, kao što su: fizičke, hemijske i biološke karakteristika zemljišta i klimatski faktori. U procesima razgradnje pesticida u zemljištu značajnu ulogu imaju mikroorganizmi, imajući u vidu da su sposobni da iz njihovih molekula koriste biogene elemente i energiju za svoje fiziološke procese. S druge strane, pesticidi koji su sami po sebi manje ili više toksične supstance, mogu štetno da deluju na populacije mikroorganizma i da dovedu do zaustavljanja njihovog razvoja, smanjenja brojnosti, osiromašenja taksonomskog sastava, stvaranja zajednica sa nižim stepenom raznovrsnosti i smanjenom fiziološkom aktivnošću. U ovom radu razmatraju se uzajamni procesi i odnosi koji se uspostavljaju u zemljištu između pesticida i mikroorganizama neposredno, kao i u periodu posle primene. Kao pokazatelji ovih procesa dati su podaci o promeni brojnosti pojedinih sistematskih i fizioloških grupa mikroorganizama, mikrobiološke biomase i aktivnosti enzima koji su nastali pod uticajem pesticida

Zajednica Arctio-Artemisetum vulgaris (Tx. 1942) Oberd. et al. 1967.: najzastupljenija ruderalna zajednica na području Pančevačkog rita

A several-year investigation of distribution, phytocoenological differentiation, floristic composition and structure of the ruderal flora and vegetation, and relative anthropogenic influences was conducted in the area of Pančevački rit. The study focused on the ruderal community Arctio-Artemisetum vulgaris, the most widespread of 10 ruderal communities identified in a detailed phytocoenological analysis of the location of Pančevački rit.Na području Pančevačkog rita su obavljena višegodišnja floristička istraživanja rasprostranjenosti, fitocenološke diferenciranosti, strukturalne i antropogene uslovljenosti ruderalne vegetacije. U radu je analizirana zajednica Arctio-Artemisetum vulgaris, koja predstavlja najrasprostranjeniju zajednicu od 10 razvijenih i opisanih ruderalnih zajednica na prostoru Pančevačkog rita

Delovanje metribuzina na aktivnost nekih enzima u zemljištu

Eeffects of metribuzin on the activity of some enzymes in soil was investigated. Trials were set up in the laboratory on a clay loam soil. Metribuzin was applied at 12.0, 24.0 and 60.0 mg/kg soil rates and soil samples were collected 3, 7, 15, 30 and 45 days after metribuzin treatment for analyses. Alkaline phosphatase, acid phosphatase, dehydrogenase, urease and β-glucosidase were recorded. The results showed that the intensity of metribuzin effects on the activity of enzymes depended on treatment rate, exposure time and enzyme group. Metribuzin had an inhibiting effect on acid phosphatese and dehydrogenase, as well as on alkaline phosphatase in the initial stage before it turned into a stimulating one, while metribuzin stimulated urease and had no effect on β-glucosidase.U radu je ispitivano delovanje metribuzina na aktivnost nekih enzima u zemljištu. Ogled je postavljen u laboratorijskim uslovima na zemljištu tipa černozem. Metribuzin je primenjen u količinama 12,0, 24,0 i 60,0 mg/kg zemljišta, a uzorci za analizu uzimani su 3, 7, 15, 30 i 45 dana posle primene metribuzina. Praćena je aktivnost enzima alkalna i kisela fosfataza, dehidrogenaza, ureaza i β-glukozidaza. Dobijeni rezultati su pokazali da delovanje metribuzina na aktivnost enzima zavisi od primenjene količine, dužine delovanja i vrste enzima. Metribuzin je delovao inhibitorno na kiselu fosfatazu i dehidrogenazu, na alkalnu fosfatazu prvo je delovao inhibitorno, a kasnije stimulativno, na ureazu je delovao stimulativno, dok na β-glukozidazu nije delovao