Uticaj gustine useva na floristički sastav i građu korovske zajednice kukuruza u uslovima primene herbicida

Effects of crop density and herbicide application on distribution of weed species within maize weed community in the location of Zemun Polje were studied. During the maize growing season in 1996 and 1997, floristic composition and structure of weed community were surveyed. Furthermore, number of species, number of plants per species and fresh weight of all weeds per area unit over all densities in both, treated and nontreated variants, were also determined. Changes, occurring under effects of higher maize crop densities and herbicide application, were analyzed on the basis of distributed weed species and their plants per species. Moreover, relative distribution of certain weed groups was determined. Significant effects of crop density x herbicide application interaction were observed in reduction of relative distribution of certain broad leafed and perennial weeds within total maize weediness at Zemun Polje.Proučavan je uticaj gustine gajenja useva i primene herbicida na zastupljenost vrsta korova u korovskoj zajednici kukuruza, na lokalitetu Zemun Polja. Tokom vegetacionog perioda kukuruza u 1996. i 1997. godini, sniman je floristički sastav i građa korovske zajednice i utvrđen broj vrsta, broj njihovih jedinki i sveža masa svih korova po jedinici površine, u svakoj gustini. Na varijanti sa i bez primene herbicida. Na osnovu zastupljenosti vrsta korova i njihovih jedinki analizirane su promene nastale pod uticajem povećanja gustine kukuruza i usled primene herbicida i izračunata relativna zastupljenost pojedinih grupa korova. U obe godine ispitivanja došlo je do redukcije korovske zajednice sa povećanjem gustine useva u uslovima bez, a naročito u uslovima sa primenom herbicida. Značajan uticaj interakcije gustine i primene herbicida je ostvaren kod smanjenja relativnog učešća grupe uskolisnih i višegodišnjih korova u ukupnoj zakorovljenosti kukuruza Zemun Polja

Geodiverzitet i geonasleđe - novi pristup tumačenju pojmova

Incomplete definitions of geodiversity and geoheritage caused the domination of clearly geological approach to these scientific problems. That is the reason why some of the integral elements of geographical environment were neglected. Wrong theoretical assumptions reflected negatively the determination and advancement of this scientific discipline. The reasons for such condition are mentioned in the paper, as well as the necessity of different and more comprehensive perspective of geodiversity and geoheritage, by which the directions of the future development are implied. .Nepotpune definicije geodiverziteta i geonasleđa uzrokovale su dominaciju čisto geološkog pristupa ovim naučnim problemima. To je razlog što su neki od sastavnih segmenata geografske sredine bili zanemareni. Pogrešne teorijske postavke negativno su se odrazile na utvrđivanje i unapređenje ove naučne oblasti. U radu su navedeni razlozi ovakvog stanja, ukazano je na potrebu drugačijeg i obuhvatnijeg sagledavanja geodiverziteta i geonasleđa, čime se nagoveštavaju pravci budućeg razvoja.

Geodiverzitet i geonasleđe - novi pristup tumačenju pojmova

Incomplete definitions of geodiversity and geoheritage caused the domination of clearly geological approach to these scientific problems. That is the reason why some of the integral elements of geographical environment were neglected. Wrong theoretical assumptions reflected negatively the determination and advancement of this scientific discipline. The reasons for such condition are mentioned in the paper, as well as the necessity of different and more comprehensive perspective of geodiversity and geoheritage, by which the directions of the future development are implied. .Nepotpune definicije geodiverziteta i geonasleđa uzrokovale su dominaciju čisto geološkog pristupa ovim naučnim problemima. To je razlog što su neki od sastavnih segmenata geografske sredine bili zanemareni. Pogrešne teorijske postavke negativno su se odrazile na utvrđivanje i unapređenje ove naučne oblasti. U radu su navedeni razlozi ovakvog stanja, ukazano je na potrebu drugačijeg i obuhvatnijeg sagledavanja geodiverziteta i geonasleđa, čime se nagoveštavaju pravci budućeg razvoja.

Uticaj pleistocenske glacijacije na morfološku raznolikost uvala Durmitora i Žijova

The alternation of glacial and carts processes as the consequence of frequent changes of glacial and interglacial phases could be recognized at the mountains Durmitor and Žijovo. Re-modeling of glacial morphology (cirques and trough valleys) carved currently karst topography with domination of uvalas. Their size and shape vary considerably as the consequence of differences within the preexisting glacial forms. Duration and intensity of kartification, which re-modeled former glacial forms into karst landforms, determine the degree of uvalas development and formation of three distinct evolution types of high-mountainous uvalas: glacial, glacial-karst and glaciofluvial.Kao posledica čestih smena glacijalnih i interglacijalnih faza na planinama Durmitor i Žijovo dolazi do smena glacijalnog i kraškog procesa. Premodeliranjem glacijalne morfologije (cirkovi i valovi) izgrađuje se savremeni kraški reljef u kome dominiraju uvale. Različita veličina i oblik uvala posledica je različitosti glacijalnih oblika koji su im prethodili. Trajanje i intenzitet kraškog procesa, kojima su nekadašnji glacijalni oblici premodelirani u kraške, odredili su stepen razijenosti uvala i izgradnju tri evolutivna tipa visokoplaninskih uvala: glacijalne, glacijalno-kraške i glacijalno-fluvijalne uvale

Uticaj pleistocenske glacijacije na morfološku raznolikost uvala Durmitora i Žijova

The alternation of glacial and carts processes as the consequence of frequent changes of glacial and interglacial phases could be recognized at the mountains Durmitor and Žijovo. Re-modeling of glacial morphology (cirques and trough valleys) carved currently karst topography with domination of uvalas. Their size and shape vary considerably as the consequence of differences within the preexisting glacial forms. Duration and intensity of kartification, which re-modeled former glacial forms into karst landforms, determine the degree of uvalas development and formation of three distinct evolution types of high-mountainous uvalas: glacial, glacial-karst and glaciofluvial.Kao posledica čestih smena glacijalnih i interglacijalnih faza na planinama Durmitor i Žijovo dolazi do smena glacijalnog i kraškog procesa. Premodeliranjem glacijalne morfologije (cirkovi i valovi) izgrađuje se savremeni kraški reljef u kome dominiraju uvale. Različita veličina i oblik uvala posledica je različitosti glacijalnih oblika koji su im prethodili. Trajanje i intenzitet kraškog procesa, kojima su nekadašnji glacijalni oblici premodelirani u kraške, odredili su stepen razijenosti uvala i izgradnju tri evolutivna tipa visokoplaninskih uvala: glacijalne, glacijalno-kraške i glacijalno-fluvijalne uvale

Protection of hydrological heritage sites of Serbia: Problems and perspectives

Protection of hydrological heritage sites, water protection segment, is an integral part of nature con¬servation. Today it is the basic theme of the hydrological heritage, the new field of hydrology and geo¬heritage, which, by exploring and evaluating hydrological diversity of a particular area and identifying representative water phenomena, sets their preservation and protection as one of the utmost objec¬tives. Two main problems in the protection of water phenomena in Serbia are: inadequate attitude of the individual and society, as a result of poor knowledge of the characteristics and values of waters, and the ever–present need for men to use them (as resources). Lack of understanding, in the profession¬al sphere, the value and importance of water phenomena in the natural system – as a result of a firmly based biocentrism in nature conservation, lack of hydrologic group within the geoheritage and a small number of interested professionals are some of the associated problems that limit the activities in this field. Specific problems – from the lack of organized and synchronized scientific research to the lack of a database on the hydrological heritage sites, are somewhat common to other segments of the na¬ture conservation of Serbia. There are three possible directions of the future actions on the protection of hydrological heritage sites of Serbia: complete protection, protection with utilisation for the needs of tourism and protection with utilisation for the needs of water management. The most complex task of hydrological heritage will just be to combine the preservation and protection with tourism and wa¬ter management, because it is diverse and often conflicting industries about. A possible solution to this problem is illustrated through the idea of water reserves

Brza procena obezbeđenosti biljaka azotom - mogućnost korišćenja SPAD hlorofilmetra

The main objective of this study was to test the possibility to use the SPAD-meter as an appropriate tool for the fast estimation of a nitrogen status in both, Italian ryegrass (Lolium italicum L.) and catch weed (Galium aparine L.) that occurred as a predominate Italian ryegrass weed species. The measurements of the SPAD-units were conducted four times (from the stage of the Italian ryegrass stem elongation to the seed ripening stage, in two-week intervals) during the growing season, followed by the chemical analyses of nitrogen in the same leaf material. The high correlation between the leaf nitrogen content (expressed as a percentage per dry weight basis) and SPAD-units, were found in all treatments (varying from 0.75 lt Rxy≤0.90 to 0.90 lt Rxy≤0.99). Obtained results showed that method based upon using a SPAD chlorophyll meter was suitable for a quick estimation of the nitrogen status in plants.U ovom radu ispitivana je mogućnost korišćenja ručnog prenosnog SPAD (Spectral Plant Analysis Diagnostic) hlorofilmetra (SPAD-502) za brzo merenje sadržaja azota u usevu Lolium italicum L. i korovskoj vrsti Galium aparine L. Na osnovu korelacione analize utvrđeno je da postoji jaka do vrlo jaka pozitivna zavisnost (od 0,75 lt Rxy≤0,90 do 0,90 lt Rxy≤0,99) između sadržaja azota u biljkama određenog standardnom hemijskom (Kjeldahlovom) metodom i procene njegovog sadržaja dobijenog na osnovu SPAD očitavanja. Dobijeni rezultati ukazuju da je metoda zasnovana na korišćenju SPAD hlorofilmetra podesna za brzu procenu obezbeđenosti biljaka azotom

Mogućnosti primene sulfonilurea i triketonskih herbicida u usevu samooplodnih linija kukuruza

Herbicide efficacy is one of the most important herbicide properties. In addition to efficacy, the herbicide should possess certain selectivity for the crops. If there is not selectivity, it is possible to damage the plants after herbicide application, which can lead to loss of yield. The growing technology of broad row crops, such as maize, involves the application of herbicides as a measure of weed control. The aim of this study was to examine the selectivity of sulfonylurea and triketons herbicides applied in five lines, following visual plant changes (EWRC) and grain yield. Herbicides were applied at recommended doses for the production of hybrid maize, as well as in double doses. The applied triketons (mesotrione and topramezone) did not cause significant damage to the lines tested, unlike sulfonylureas (rimsulfuron and foramsulfuron). Sulfonylureas significantly influence of grain yield, the highest in early maturity group lines. Triketons had no effect on grain yield of maize lines examined.Efikasnost prema korovima je jedna od najbitnijih osobina herbicida. Pored efikasnosti, herbicid bi trebalo da poseduje i odgovarajuću selektivnost prema usevu u kome se primenjuje. Ukoliko se selektivnost herbicida nedovoljno poznaje moguće je da dođe do oštećenja useva posle primene, što može dovesti i do gubitka prinosa. Tehnologija gajenja širokorednih useva, kakav je kukuruz, podrazumeva primenu herbicida, kao meru suzbijanja korova. Cilj ovog rada je bio da se ispita selektivnost sulfonilurea i triketonskih herbicida u usevu pet linija kukuruza, praćenjem vizuelnih promena na samim gajenim biljakama (EWRC) i prinosa zrna. Herbicidi su primenjeni u količinama preporučenim za proizvodnju hibridnog kukuruza, kao i u dvostruko većim. Triketonski herbicidi (mezotrion i topramezon) nisu izazvali značajna oštećenja na ispitivanim linijama, za razliku od sulfonilurea herbicida (rimsulfuron i foramsulfuron). Prinos zrna linija kukuruza pod uticajem sulfonilurea je značajno varirao, najviše kod linija ranih grupa zrenja. Triketonski herbicidi nisu imali uticaja na prinos zrna ispitivanih linija kukuruza

Foliar fertilizer increases herbicide tolerance in maize inbred lines

Plant response to herbicides is very important in agriculture, especially in maize seed production. Due to inbreeding process, inbred lines are more susceptible to herbicides comparing to hybrids. Herbicide application is still the most effective method for weed control. Also, insufficient herbicide selectivity can be limited factor in seed crop production. Herbicides can cause visual plant damages or slow down plant development and finally decrease grain yield. On the other hand, dominance of grass weeds in maize crop occurs due to a lack of selective herbicides for their control. With sulfonylurea herbicides this problem became under control, but a problem with selectivity is still present, particularly in maize seed crop. Optimal plant nutrition provides better crop fitness and higher tolerance to herbicides. In case of foliar fertilizing, fast entry of macro- and micro-elements into plants also influence better plants response to herbicides and other negative impacts. The effect of sulfonylureas and foliar fertilizer on five maize lines was evaluated in three year field experiment. This was done by visual estimation, grain yield measuring, as well as the alterations in the content of antioxidants such as phenolics free thiolic groups, and soluble proteins in the leaves. Positive effects of applied foliar fertilizer were observed on grain yield. Most of the genotypes expressed significant increase of grain yield in the treatments with foliar fertilizer, compared to control and analogous treatments with herbicides. Alternations in free thiolic groups and phenolics content was significantly influenced by applied treatments. The differences in the content of phenolics and thiolic groups in the treatments with herbicides + foliar fertiliser indicated that herbicide stress was more rapidly overcome. On the other hand, soluble protein content did not vary significantly maize leaves from observed treatments

Водни потенцијал и хидрогеографска рејонизација Ваљевских планина

Ваљевске планине су део јединственог венца Подрињско–ваљевских планина, који представља истакнуту црту рељефа западне Србије. Простиру се у смеру запад–северозапад – исток–југоисток, од превоја Прослоп, који одваја Соколске планине (подрињски низ) од Медведника (ваљевски низ) до Проструге, на крајњим североисточним обронцима Рајца изнад Бољковачког раседа. Ваљевске планине чине: Медведник, Јабланик, Повлен, Магљеш, Маљен, Сувобор и Рајац. Природна разноликост Ваљевских планина од литолошке грађе, преко климатских одлика до биљног покривача резултирала је разноврсношћу вода и њихових појава. Тиме је иницирано ово истраживање, са циљем детаљног упознавања особености – богатства и разноврсности површинских вода овог краја и њихових односа, као и природно–географских услова који су их обликовали...The Valjevo mountain range is part of a unique range of Podrinje–Valjevo Mountains, which at the same time represents a prominent characteristic of western Serbia relief. Valjevo mountains stretch in the west–northwest – east–southeast direction, from Proslop mountain pass, which separates Sokolske mountains (Podrinje range) from Medvednik (Valjevo range), all the way to Prostruga at the farthest northeast slopes of Rajac mountain above Boljkovački fault. Valjevo mountains include Medvednik, Jablanik, Povlen, Maglješ, Maljen, Suvobor and Rajac. The natural diversity of Valjevo mountains including their lithological composition, climatic features and plant cover has resulted in a variety of waters and their phenomena. This fact initiated a detailed research of the richness and diversity of surface waters in this area and their relationships, as well as of natural and geographical conditions that formed these phenomena..