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Water excess and water deficit risk assessment in landreclamation area
Full text linkUčestale smene veoma vlažnih i izuzetno sušnih perioda mogu prouzrokovati značajne negativne posledice na poljoprivredu, životnu sredinu, ekonomiju i na društvo u celini. Strogi zahtevi poljoprivredne proizvodnje i specifičnosti agroklimatskih uslova i samog područja Vojvodine čine ga veoma vulnerabilnim na pojavu viška ili manjka vode. Jasnije sagledavanje vremenske i prostorne pojave viška i manjka vode i procena rizika od njihove pojave moglo bi dovesti do preduzimanja odgovarajućih mera pripreme i ublažavanja negativnih posledica i pre pojave hazardnog događaja. U ovom radu su kreirane metodologije na osnovu kojih su izvršene procene rizika od suficita i deficita vode na melioracionom području Vojvodine. Procene rizika dobijene su kombinacijom procena ranjivosti i procena hazarda, a baziraju se na identifikaciji ključnih faktora koji utiču na pojavu suficita i deficita vode, na njihovoj analizi i adekvatnom vrednovanju i uz korišćenje geografskog informacionog sistema. Ključni faktori su odabrani na osnovu njihovog uticaja na samu pojavu ili na ublažavanje efekata suše ili pojave viška vode, na osnovu dostupnosti podataka i na osnovu istraživanja brojnih autora. Vrednovanje faktora ranjivosti je izvršeno objektivnom metodom entropije. Analize hazarda su izvršene savremenim hidrometeorološkim stohastičkim metodama koje sveobuhvatno sagledavaju opasnosti od pojave suše ili viška vode. Rezultati procena ranjivosti, hazarda i rizika su dobijene korišćenjem geografskog informacionog sistema u vidu karata. Metodologije na osnovu kojih su u ovom radu sprovedene procene rizika od suficita i deficita vode na melioracionom području Vojvodine, omogućavaju stvaranje uslova za podizanje pripravnosti na pojavu ekstremnih hidrometeoroloških događaja, unapređenje planiranja meliorativnih mera kao i izbor i donošenje optimalnijih odluka vezanih za upravljanje i ulaganje u meliorativne sisteme, a sve u skladu sa načelima i principima održivog razvoja poljoprivrede, vodoprivrede i melioracija.Frequent changes of very dry and wet periods can cause significant adverse effects on agriculture, environment, economy and the whole society. Strict requirements of agricultural production and special characteristics of agro-climatic conditions of the Vojvodina region makes it very vulnerable to the occurrences of excess water or drought. A clearer understanding of the temporal and spatial occurrence of excess water or droughts and the risk assessment of their occurrence could lead to taking appropriate measures of preparedness and mitigation of negative impacts before the onset of hazardous events. In this dissertation, methodologies of risk assessments of water excess and water deficit on the land reclamation areas in Vojvodina were created. Risk assessments were obtained by a combination of vulnerability assessments and hazard assessments, and they are based on the identification of key factors affecting the occurrence of water excess and water deficit, on their analysis and adequate evaluation and by using geographic information systems. Key factors were selected based on their impact on the occurrence or on mitigation of the effects of drought or excess water, on the basis of data availability and based on the research of numerous authors. Valuation of the vulnerability factors is made by objective method of entropy weighting. Hazard analyses were performed by using contemporary hydrometeorological stochastic methods that comprehensively perceive threats of drought or excess water. Assessments of vulnerability, hazard and risk are preformed in GIS and results are presented in a form of thematic maps. Methodologies for risk assessments of water excess and water deficit in land reclamation areas of Vojvodina region, created or modified in this dissertation, allows the creation of conditions for increasing preparedness to extreme hydro-meteorological events, improvement of land reclamation measures planning as well as improvement of selection and decision-making regarding management and investment in the irrigation and drainage systems, all in accordance with the principles of sustainable agriculture, water management and land reclamation.
Water excess and water deficit risk assessment in landreclamation area
No full textUčestale smene veoma vlažnih i izuzetno sušnih perioda mogu prouzrokovati značajne negativne posledice na poljoprivredu, životnu sredinu, ekonomiju i na društvo u celini. Strogi zahtevi poljoprivredne proizvodnje i specifičnosti agroklimatskih uslova i samog područja Vojvodine čine ga veoma vulnerabilnim na pojavu viška ili manjka vode. Jasnije sagledavanje vremenske i prostorne pojave viška i manjka vode i procena rizika od njihove pojave moglo bi dovesti do preduzimanja odgovarajućih mera pripreme i ublažavanja negativnih posledica i pre pojave hazardnog događaja. U ovom radu su kreirane metodologije na osnovu kojih su izvršene procene rizika od suficita i deficita vode na melioracionom području Vojvodine. Procene rizika dobijene su kombinacijom procena ranjivosti i procena hazarda, a baziraju se na identifikaciji ključnih faktora koji utiču na pojavu suficita i deficita vode, na njihovoj analizi i adekvatnom vrednovanju i uz korišćenje geografskog informacionog sistema. Ključni faktori su odabrani na osnovu njihovog uticaja na samu pojavu ili na ublažavanje efekata suše ili pojave viška vode, na osnovu dostupnosti podataka i na osnovu istraživanja brojnih autora. Vrednovanje faktora ranjivosti je izvršeno objektivnom metodom entropije. Analize hazarda su izvršene savremenim hidrometeorološkim stohastičkim metodama koje sveobuhvatno sagledavaju opasnosti od pojave suše ili viška vode. Rezultati procena ranjivosti, hazarda i rizika su dobijene korišćenjem geografskog informacionog sistema u vidu karata. Metodologije na osnovu kojih su u ovom radu sprovedene procene rizika od suficita i deficita vode na melioracionom području Vojvodine, omogućavaju stvaranje uslova za podizanje pripravnosti na pojavu ekstremnih hidrometeoroloških događaja, unapređenje planiranja meliorativnih mera kao i izbor i donošenje optimalnijih odluka vezanih za upravljanje i ulaganje u meliorativne sisteme, a sve u skladu sa načelima i principima održivog razvoja poljoprivrede, vodoprivrede i melioracija.Frequent changes of very dry and wet periods can cause significant adverse effects on agriculture, environment, economy and the whole society. Strict requirements of agricultural production and special characteristics of agro-climatic conditions of the Vojvodina region makes it very vulnerable to the occurrences of excess water or drought. A clearer understanding of the temporal and spatial occurrence of excess water or droughts and the risk assessment of their occurrence could lead to taking appropriate measures of preparedness and mitigation of negative impacts before the onset of hazardous events. In this dissertation, methodologies of risk assessments of water excess and water deficit on the land reclamation areas in Vojvodina were created. Risk assessments were obtained by a combination of vulnerability assessments and hazard assessments, and they are based on the identification of key factors affecting the occurrence of water excess and water deficit, on their analysis and adequate evaluation and by using geographic information systems. Key factors were selected based on their impact on the occurrence or on mitigation of the effects of drought or excess water, on the basis of data availability and based on the research of numerous authors. Valuation of the vulnerability factors is made by objective method of entropy weighting. Hazard analyses were performed by using contemporary hydrometeorological stochastic methods that comprehensively perceive threats of drought or excess water. Assessments of vulnerability, hazard and risk are preformed in GIS and results are presented in a form of thematic maps. Methodologies for risk assessments of water excess and water deficit in land reclamation areas of Vojvodina region, created or modified in this dissertation, allows the creation of conditions for increasing preparedness to extreme hydro-meteorological events, improvement of land reclamation measures planning as well as improvement of selection and decision-making regarding management and investment in the irrigation and drainage systems, all in accordance with the principles of sustainable agriculture, water management and land reclamation.
The Effect of Irrigation Treatments and Sowing Periods on Water Use Efficiency, Yield and Quality of Common Bean
No full textавремено друштво се сусреће са врло озбиљним изазовима у пољопривредној
производњи, а везано за све веће захтеве за храном као и недостатком воде у овом сектору.
Полазећи од ових чињеница, истраживање које је описано у овој дисертације је првенствено
посвећено рационалном коришћењу водних ресурса и проналажењу начина како повећати
производњу хране.
Циљ ове докторске дисертације био је да се испита утицај режима наводњавања и рока
сетве на ефикасност коришћења воде, принос и квалитет зрна пасуља. Истраживање је
вршено на пасуљу сорте сремац. Постављен је двофакторијални оглед по split plot плану
(плану подељених парцела) у три понављања. Први фактор (парцела) био је рок сетве: сетва
у редовном року, половином априла (I) и две касне сетве (крај маја/почетак јуна (II) и крај
јуна/почетак јула (III)). Други фактор (подпарцела) био је режим наводњавања (третман
пуног наводњавања (Ф) и два третмана редукованог наводњавања (Д1 и Д2)). Трогодишње
истраживање у периоду од половине априла до почетка октобра (2018, 2019. и 2020. године)
извршено је на огледном пољу компаније „Напредак“ а. д. Стара Пазова. Све три године биле
су веома топле, али истовремено и веома кишне. Сума падавина током истраживаног
периода варирала је од 590 mm (2019) до 434 mm (2020) године, што је далеко изнад
просечне вредности за овај период која износи 359 mm.
У оквиру испитиваних фактора (рок сетве и режим наводњавања) праћена је фенологија
пасуља, влажност земљишта, покровност земљишта, акумулација суве биомасе, индекс лисне
површине, потрошња воде пасуља, стање вегетације и снабдевеност водом, принос пасуља,
принос суве биомасе, број махуна по биљци, маса 1000 зрна, жетвени индекс, хемијске
особине зрна пасуља (садржај протеина и уља), као и продуктивност воде и ефикасност
коришћења воде. У раду су, поред осталих, примењене савремене методе даљинске детекције
(мултиспектрални и термални снимци).
Највеће вредности садржаја воде у земљишту регистроване су у оквиру Ф третмана у
свим испитиваним роковима сетве, и овај садржај воде није се спуштао испод границе лако
приступачне воде биљкама, изузев током сазревања. Режим пуног наводњавања (Ф)
остварио је значајно већу (p<0,05) акумулацију биомасе и проценат покровности земљишта у
поређењу са Д2 третманом, док се третман Д1 није значајно разликовао.
Режим наводњавања и рокови сетве испољили су статистичку значајност на промену
вредности стварне евапотранспирације. Утврђена је разлика у просечним вредностима
стварне евапотранспирације између третмана наводњавања и између појединих рокова сетви.
У трогодишњем периоду у првом року сетве у просеку је трошено 383,4 mm, у другом 407,9
mm а у трећем 360,0 mm. На варијанти са пуним наводњавањем у просеку је потрошено
401,7 mm, док је потрошња воде на третманима редукованог заливања мања у односу на Ф
третмане (383,1 mm и 366,9 mm на третманима Д1 и Д2, редом).
Израчунати вегетациони индекси (NDVI - вегетациони индекс нормализоване разлике;
GNDVI - зелени вегетациони индекс нормализоване разлике; MCARI1 - модификовани
индекс абсорпције хлорофила у рефлексији) добијени су на основу мултиспектралних
снимака беспилотном летелицом (дроном). Вредности NDVI, MCARI1 и GNDVI су
статистички значајно више у Ф третману него на третманима редукованог наводњавања.
Вегетациони индекси NDVI, MCARI1, и GNDVI били су у доброј до јакој корелацији са
величинама на које утиче режим наводњавања: покривеношћу, индексом лисне површине и
транспирацијом, али и у задовољавајућој корелацији са вредностима влажности земљишта...Modern society is facing serious challenges in agricultural production related to increasing
food demand and water scarcity. Based on these facts, the research described in this dissertation is
primarily dedicated to the rational use of water resources and finding ways to ramp up food
production.
The aim of this doctoral dissertation was to examine the impact of irrigation regimes and
sowing periods on water use efficiency, yield, and grain quality of beans, specifically the sremac
bean variety. The research was conducted in a two-factorial trial using a split-plot design divided
into three repetitions. The first factor (plot) was the sowing period, including sowing in the regular
term, mid-April (I) and two late sowings (end of May/beginning of June (II) and end of
June/beginning of July (III)). The second factor (subplot) was the irrigation regime, which included
full irrigation treatment (F) and two deficit irrigation treatments (D1 and D2). The three-year study
was conducted from mid-April to early October (2018, 2019, 2020) on the experimental field of the
company "Napredak" a.d. Stara Pazova. All three years were warm and rainy, with total
precipitation during the study period ranging from 590 mm (2019) to 434 mm (2020), which is well
above the average value of 359 mm for this period.
Within the framework of the examined factors (sowing period and irrigation regime), the
following aspects were monitored: phenology of beans, soil moisture, canopy cover, dry biomass
accumulation, leaf area index, water consumption of common bean, plant health and water status,
grain yield, dry biomass yield, number of pods per plant, 1000-grain weight, harvest index,
chemical properties of bean grains (protein and oil content), and water productivity and water use
efficiency. The research also applied modern remote sensing methods, including multispectral and
thermal images.
The highest soil moisture was observed in the F treatment (full irrigation) during all three
sowing periods and water content did not drop below the readily avaliable water level, except
during maturation. The full irrigation regime (F) achieved significantly higher (p<0.05) biomass
accumulation and canopy cover compared to the D2 treatment, while the D1 did not differ
significantly.
The effect of the irrigation regime and sowing period was statistically significant in changing
the values of actual evapotranspiration. The difference in average values of actual
evapotranspiration between irrigation treatments and between sowing periods was determined. In
the three-year period, an average of 383.4 mm was spent in the first sowing period, 407.9 mm in the
second, and 360.0 mm in the third. In the full irrigation treatment, an average of 401.7 mm was
consumed, while water consumption in deficit irrigation treatments was lower compared to the F
treatment (381.1 mm and 366.9 mm in the D1 and D2 treatments, respectively)
Calculated vegetation indices (NDVI - normalized difference vegetation index, GNDVI -
green normalized difference vegetation index, and MCARI1 - modified chlorophyll absorption ratio
index at 700 nm) were obtained from multispectral images taken by an unmanned aerial vehicle
(drone). The values of NDVI, MCARI1 and GNDVI were significantly higher in the F treatment than
in the deficit irrigation treatments. Vegetation indices NDVI, MCARI1, and GNDVI were in good to
strong correlation with the variables affected by the irrigation regime: canopy cover, leaf area index
and transpiration, as well as satisfactory correlation with soil moisture values. The high correlations
of the NDVI, MCARI1 and GNDVI indices with the detection of differences in irrigation regimes
qualify them as a reliable tools for estimating bean yields..
Wind Erosion Quantification Process in DeliblatoSands
Full text linkErozija predstavlja vrlo složen fizički proces u kome pod dejstvom atmosferskih sila nastaju destruktivne promene na površinskom sloju zemljišta. Kada je osnovni agens pokretanja čestica zemljišta vetar, govori se o eroziji vetrom ili eolskoj eroziji. Eolska erozija je specifičan proces koji se odvija u izrazito složenim okolnostima uzajamnog delovanja brojnih prirodnih i antropogenih faktora uglavnom stohastičkog karaktera, zbog čega je njeno istraživanje kompleksan naučno-istraživački problem. Osnovni cilj sprovedenih istraživanja je bio da se na izabranim lokalitetima Deliblatske peščare, najvećeg i najznačajnijeg područja takve vrste u Evropi, uspostavi praćenje stanja procesa eolske erozije, odnosno neposrednim, sistematskim merenjima u terenskim uslovima ustanove količine eolskog nanosa – pronos nanosa, odrede dominantni pravci njegovog kretanja, definiše njegova unutargodišnja raspodela i utvrdi efekat vegetacije na smanjenje intenziteta eolske erozije. U toku četvorogodišnjeg perioda su po prvi put na ovim prostorima, na istom lokalitetu, sprovedena uporedna istraživanja eolske erozije primenom mehaničkih hvatača nanosa i metoda zasnovanih na praćenju aktivnosti radionuklida veštačkog porekla 137Cs u zemljištu, čije količine služe da se posebnim teorijskim modelima pretvore u gubitke zemljišta. Praćenje procesa eolske erozije je vršeno od 2006. do 2009. godine na lokalitetu Cvjićev vis, koji je izabran kao karakterističan, jer je pored centralne pozicije na Deliblatskoj peščari, obrađivani površinski sloj zemljišta bio bez zaštite od vetra. Paralelno sa ovim merenjima, na lokalitetu Dragićev hat – rasadnik, praćenje procesa eolske erozije vršeno je na dva merna mesta u periodu od maja 2006. godine do aprila 2007. godine u uslovima postojanja zaštitne uloge vegetacionog pokrivača i/ili vegetacionog pojasa. Merenje intenziteta eolske erozije je realizovano statičnim hvatačima nanosa tipa deflametar (dimanzija ulaznog otvora 10 x 10 cm) orijentisanih prema određenim pravacima (N, NE, E, SE, S, SW, W, NW) da bi potpuno definisali procese eolske erozije u vektorskom smislu. Kvantifikacija eolskog nanosa statičnim hvatačima stalno usmerenim prema određenim pravcima duvanja vetrova, omogućila je da se posebno evidentiraju i razlikuju „sumarna” produkcija eolskog nanosa (aritmetički zbir zahvaćenih količina nanosa iz svih hvatača) i „rezultujuća” količina eolskog nanosa (vektorski zbir), jer te veličine određuju pored ukupno pokrenute količine eolskog nanosa (produkcija nanosa) i delove nanosa koji se transportuju van granica erozionog polja (gubitak zemljišta), generalni pravac i smer njegovog kretanja. Merenja eolske erozije na lokalitetu Cvijićev vis za period 2006-2009. godine su ukazala na značajne procese eolske erozije koji su definisani srednjim godišnjim pronosom nanosa od 4,48 kg m-1. Ustanovljeno je da su ukupno zahvaćene količine nanosa na 8 hvatača bile Σ = 25,94, 20,92, 52,98 i 43,47 kg m-1 god-1, a pronosi nanosa Σ' (Σ/8) = 3,24, 2,61, 6,62 i 5,43 kg m-1 god-1 u 2006., 2007., 2008. i 2009. godini respektivno. Pronosi nanosa za period od maja 2006. do aprila 2007. godine su pokazali da je na lokalitetu Cvijićev vis koga karakterišu neobraslost i otvorenost površine zabeležen najveći intenzitet eolske erozije na godišnjem nivou koji je 4 puta veći u odnosu na lokalitet Dragićev hat – rasadnik I koga karakterišu neobraslost i zaštićenost površine i 30,2 puta veći u odnosu na Dragićev hat – rasadnik II koga karakterišu obraslost i zaštićenost zemljišta. Na lokalitetu Dragićev hat – rasadnik I intenzitet eolske erozije na godišnjem nivou je 7,5 puta veći od onog na lokalitetu Dragićev hat – rasadnik II. Gubici zemljišta izraženi preko rezultujućih mesečnih pronosa nanosa (vektorski zbir) iznosili su 5,13, 2,04, 4,31 i 11,94 kg m-1 u 2006., 2007., 2008. i 2009. godini respektivno, a procentualni udeo godišnjih gubitaka zemljišta u odnosu na ukupnu produkciju nanosa (aritmetički zbir) se kretao od 8,1% do 27,5. Rezultujući pravac kretanja eolskog nanosa u toku perioda istraživanja bio je jugoistok - severozapad (SE-NW) pod uticajem dominantnog jugoistočng vetra „Košava”. Iako se najpouzdanije determinisanje eolske erozije i njenih efekata postiže na osnovu neposrednih sistematskih merenja u realnim terenskim uslovima, počev od kraja prošlog veka se sve više primenuju i metode praćenja radionuklida iz radioaktivnih padavina, posebno 137Cs, u cilju procene gubitaka zemljišta i prostornog rasporeda eolskog nanosa. Ukupan broj uzetih uzoraka za metodu praćenja količina 137Cs je iznosio 149, od kojih je bilo 9 inicijalnih uzoraka (3 profila po 3 uzorka), 14 osnovnih uzoraka (2 profila po 7 uzoraka), 32 ostala uzorka (8 profila po 4 uzorka), 36 referentnih uzoraka (9 profila po 4 uzorka) i 58 uzoraka uzetih zrakasto po određenim pravcima (N, NE, E, SE, S, SW, W, NW). Osnovni uzorak na neobrađenom zemljištu sa detektovanom količinom 137Cs od 10.603,57 Bq m-2 predstavlja uporednu vrednost, tj. lokalni padavinski ulaz 137Cs za modele pretvaranja količina 137Cs u količine izgubljenog zemljišta. Ovaj uzorak odslikava sredinu na kojoj su sprovedena istraživanja i predstavlja uporednu vrednost koja može korektno da definiše procese eolske erozije. Za pretvaranje izmerenih količina 137Cs u količine izgubljenog zemljišta po modelima Walling-a korišćen je najjednostavniji proporcionalni model (PM) za obrađena zemljišta, a najprimenjeniji model profilne distribucije (PDM) za neobrađena zemljišta u okviru najnovije verzije PC-kompatibilnog softverskog paketa u Microsoft Excel Add-Ins varijanti. Modelom profilne distribucije (PDM) za sve uzorake uzete na eksperimentalnom području dobijeni su prosečni gubici zemljišta od 207,06 t ha-1 god-1 i 2,10 cm. Model Basher & Webb je dao prosečne gubitke zemljišta od 212,18 t ha-1 god-1 i 2,09 cm. Gubici zemljišta dobijeni modelima pretvaranja količina 137Cs u količine izgubljenog zemljišta ukazuju na značajne procese eolske erozije definisane jakom i ekscesivnom eolskom erozijom. Za 58 uzoraka zemljišta uzetih na tačkama raspoređenih zrakasto po određenim pravcima (N, NE, E, SE, S, SW, W, NW), pored koncentracija i količina 137Cs i 210Pbex, određene su prostorne koordinate X i Y i nadmorske visine uzetih uzoraka. Prostorne distribucije koncentracija 137Cs i 210Pbex izražene su izolinijama, a kreiranani su i 3D prikazi u procentima odstupanja 137Cs i 210Pbex od lokalnog padavinskog ulaza 137Cs i 210Pbex. U oba slučaja je primetan dominantan uticaj pravca jugoistok - severozapad (SE-NW), odnosno jugoistočnog vetra „Košava”. Komparativna analiza ovih metoda je ukazala na validnost u kvantifikaciji procesa eolske erozije i mogućnost njihove primene u budućnosti, a dobijeni rezultati produkcije eolskog nanosa i gubitaka zemljišta su dali doprinos oceni stanja degradacije zemljišta i ugroženosti Deliblatske peščare. Erosion is a very complex physical process which, under the impact of atmospheric forces, creates destructive changes on the soil surface layer. In case the primary agent of particle movement is wind, we talk about wind or aeolian erosion. Aeolian erosion is a specific process which occurs in extremely complex situations of mutual interaction of numerous natural and anthropogenic factors of mainly stochastic properties making its research a complex scientific-research problem. The main goal of conducted research was to monitor the process of aeolian erosion at the chosen localities of Deliblato Sands, the largest and the most important area of the kind in Europe. In other words, the goal is to determine the quantities of aeolian sediment – sediment transport by direct systematic measurements in field conditions, determine dominant direction of sediment transport, define its annual distribution and determine the effect of vegetation on reducing the intensity of aeolian erosion. During a four-year period, for the first time in this area, i.e. at the same locality, a comparative research of aeolian erosion have been conducted using the mechanical sediment trap and activities based on 137Cs radioisotope tracing technique for estimating soil losses using special theoretical models. The monitoring of aeolian erosion processes was conducted during the period 2006 – 2009 at Cvijićev vis which was chosen as a typical locality since it was, apart from the central position on Deliblato Sands, a cultivated surface without any wind protection. Alongside with these measurements, at Dragićev hat – nursery garden, the monitoring of aeolian erosion was conducted on two measurement points during the period May 2006 – April 2007 in areas with the protective vegetative covers and/or vegetative belts. Aeolian erosion intensity measurement was performed by static sediment traps of the type “deflametre” (dimension of entry opening 10 x 10 cm) oriented on certain directions (N, NE, E, SE, S, SW, W, NW) in order to define the aeolian erosion processes in vector terms. The quantification of aeolian sediment using static traps constantly facing certain wind blowing directions enabled to log and differentiate “summary” yield of aeolian sediment (arithmetic sum of all sediment quantities from all traps) and “resulting” quantity of aeolian sediment (vector sum), since those quantities determine not only the entire amount of transported aeolian sediment (sediment yield) but also the sediment transported outside the areas of erosion field (soil loss), bur also the general direction of its transport. Aeolian erosion measurement on Cvijićev vis for the period 2006 – 2009 indicated the significant aeolian erosion processes which were defined by medium annual ediment transport of 4.48 kg m-1. It has been determined that the total quantities of moved sediment were 25.94, 20.92, 52.98 and 43.47 kg m-1 year-1, and sediment transport 3.24, 2.61, 6.62 and 5.43 kg m-1 year-1 in 2006, 2007, 2008 and 2009 respectively. Sediment transport for the period May 2006 – April 2007 showed that on Cvijićev vis which is characterized by bareness and openness there was the biggest aeolian erosion – four times bigger compared to Dragićev hat – nursery garden I characterized by bareness and protectiveness and 30.2 times bigger compared to Dragićev hat – nursery garden II characterized by overgrown condition and protectiveness of erosive field. At the locality Dragićev hat – nursery garden I the aeolian erosion was recorded 7.5 times bigger compared to the one recorded on Dragićev hat – nursery garden II. Soil loses expressed through the resulting monthly sediment transport (vector sum) equalled 5.13, 2.04, 4.31 and 11.94 kg m-1 in 2006, 2007, 2008 and 2009 respectively, and the percentage share of annual soil losses compared to total sediment yield (arithmetical sum) varied between 8.1% and 27.5%. The resulting aeolian sediment movement direction was SE-NW under the influence of the dominant southeast wind “Koshava”. Even though the most reliable determination of aeolian erosion and its effects is based on direct systematic measurements in real time conditions in the field, starting from the end of the last century the methods of tracking radionuclide from radioactive precipitation, especially 137Cs, for the purposes of estimating the soil loss and spatial distribution of aeolian sediment, have been used increasingly. The total number of samples taken for the method of monitoring the quantity of 137Cs was 149, 9 of which were initial samples (3 profiles with 3 samples each), 14 main samples (2 profiles with 7 samples each), 32 remaining samples (8 profiles with 4 samples each), 36 reference samples (9 profiles with 4 samples each) and 58 samples taken radially on certain directions (N, NE, E, SE, S, SW, W, NW). The main sample taken from the uncultivated land with the detected quantity of 137Cs of 10,603.57 Bq m-2 represents the comparative value, i.e. local precipitation input of 137Cs for the models of 137Cs quantities conversion into the quantities of lost soil. This sample depicts the area where the research was conducted and represents the comparative value which can properly define the aeolian erosion processes. For converting the measured quantities of 137Cs into the quantities of lost soil using Walling model the simplest proportional model (PM) for cultivated land was used and the most appropriate profile distribution model (PDM) for uncultivated soil with the newest version of PC compatible software package in Microsoft Excel Add-Ins. Using the profile distribution model (PDM) on all samples taken from the experimental area the quantities of average soil loss obtained were 207.06 t ha-1 year-1 and 2.10 cm. Basher & Webb model gave the average soil loss of 212.18 t ha-1 year-1 and 2.09 cm. Soil loss calculated using the conversion of 137Cs quantities into the soil loss quantities indicate the significant aeolian processes defined by strong and excessive aeolian erosion. For 58 soil samples taken from areas radially distributed on certain directions (N, NE, E, SE, S, SW, W, NW), apart from 137Cs and 210Pbex concentrations and quantities, spatial coordinates X and Y were determined as well as the altitude of taken samples. Spatial distribution of 137Cs and 210Pbex quantities are represented by isolines, and also 3D demonstrations were created showing the percentage of deviation of 137Cs and 210Pbex from the local precipitation input of 137Cs and 210Pbex. In both cases, the dominant direction SENW was noticeable, i.e. the southeast wind “Koshava”. The comparative analysis of these methods indicated the validity in the quantification of aeolian erosion process and the possibility of its application in the future and the obtained results of aeolian sediment yield and soil loss contributed to determining the state of soil degradation and vulnerability of Deliblato Sands
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Nature-based solutions for improving drainage systems in Vojvodina, Serbia : [abstract]
Full text linkWind Erosion Quantification Process in DeliblatoSands
No full textErozija predstavlja vrlo složen fizički proces u kome pod dejstvom atmosferskih sila nastaju destruktivne promene na površinskom sloju zemljišta. Kada je osnovni agens pokretanja čestica zemljišta vetar, govori se o eroziji vetrom ili eolskoj eroziji. Eolska erozija je specifičan proces koji se odvija u izrazito složenim okolnostima uzajamnog delovanja brojnih prirodnih i antropogenih faktora uglavnom stohastičkog karaktera, zbog čega je njeno istraživanje kompleksan naučno-istraživački problem. Osnovni cilj sprovedenih istraživanja je bio da se na izabranim lokalitetima Deliblatske peščare, najvećeg i najznačajnijeg područja takve vrste u Evropi, uspostavi praćenje stanja procesa eolske erozije, odnosno neposrednim, sistematskim merenjima u terenskim uslovima ustanove količine eolskog nanosa – pronos nanosa, odrede dominantni pravci njegovog kretanja, definiše njegova unutargodišnja raspodela i utvrdi efekat vegetacije na smanjenje intenziteta eolske erozije. U toku četvorogodišnjeg perioda su po prvi put na ovim prostorima, na istom lokalitetu, sprovedena uporedna istraživanja eolske erozije primenom mehaničkih hvatača nanosa i metoda zasnovanih na praćenju aktivnosti radionuklida veštačkog porekla 137Cs u zemljištu, čije količine služe da se posebnim teorijskim modelima pretvore u gubitke zemljišta. Praćenje procesa eolske erozije je vršeno od 2006. do 2009. godine na lokalitetu Cvjićev vis, koji je izabran kao karakterističan, jer je pored centralne pozicije na Deliblatskoj peščari, obrađivani površinski sloj zemljišta bio bez zaštite od vetra. Paralelno sa ovim merenjima, na lokalitetu Dragićev hat – rasadnik, praćenje procesa eolske erozije vršeno je na dva merna mesta u periodu od maja 2006. godine do aprila 2007. godine u uslovima postojanja zaštitne uloge vegetacionog pokrivača i/ili vegetacionog pojasa. Merenje intenziteta eolske erozije je realizovano statičnim hvatačima nanosa tipa deflametar (dimanzija ulaznog otvora 10 x 10 cm) orijentisanih prema određenim pravacima (N, NE, E, SE, S, SW, W, NW) da bi potpuno definisali procese eolske erozije u vektorskom smislu. Kvantifikacija eolskog nanosa statičnim hvatačima stalno usmerenim prema određenim pravcima duvanja vetrova, omogućila je da se posebno evidentiraju i razlikuju „sumarna” produkcija eolskog nanosa (aritmetički zbir zahvaćenih količina nanosa iz svih hvatača) i „rezultujuća” količina eolskog nanosa (vektorski zbir), jer te veličine određuju pored ukupno pokrenute količine eolskog nanosa (produkcija nanosa) i delove nanosa koji se transportuju van granica erozionog polja (gubitak zemljišta), generalni pravac i smer njegovog kretanja. Merenja eolske erozije na lokalitetu Cvijićev vis za period 2006-2009. godine su ukazala na značajne procese eolske erozije koji su definisani srednjim godišnjim pronosom nanosa od 4,48 kg m-1. Ustanovljeno je da su ukupno zahvaćene količine nanosa na 8 hvatača bile Σ = 25,94, 20,92, 52,98 i 43,47 kg m-1 god-1, a pronosi nanosa Σ' (Σ/8) = 3,24, 2,61, 6,62 i 5,43 kg m-1 god-1 u 2006., 2007., 2008. i 2009. godini respektivno. Pronosi nanosa za period od maja 2006. do aprila 2007. godine su pokazali da je na lokalitetu Cvijićev vis koga karakterišu neobraslost i otvorenost površine zabeležen najveći intenzitet eolske erozije na godišnjem nivou koji je 4 puta veći u odnosu na lokalitet Dragićev hat – rasadnik I koga karakterišu neobraslost i zaštićenost površine i 30,2 puta veći u odnosu na Dragićev hat – rasadnik II koga karakterišu obraslost i zaštićenost zemljišta. Na lokalitetu Dragićev hat – rasadnik I intenzitet eolske erozije na godišnjem nivou je 7,5 puta veći od onog na lokalitetu Dragićev hat – rasadnik II. Gubici zemljišta izraženi preko rezultujućih mesečnih pronosa nanosa (vektorski zbir) iznosili su 5,13, 2,04, 4,31 i 11,94 kg m-1 u 2006., 2007., 2008. i 2009. godini respektivno, a procentualni udeo godišnjih gubitaka zemljišta u odnosu na ukupnu produkciju nanosa (aritmetički zbir) se kretao od 8,1% do 27,5. Rezultujući pravac kretanja eolskog nanosa u toku perioda istraživanja bio je jugoistok - severozapad (SE-NW) pod uticajem dominantnog jugoistočng vetra „Košava”. Iako se najpouzdanije determinisanje eolske erozije i njenih efekata postiže na osnovu neposrednih sistematskih merenja u realnim terenskim uslovima, počev od kraja prošlog veka se sve više primenuju i metode praćenja radionuklida iz radioaktivnih padavina, posebno 137Cs, u cilju procene gubitaka zemljišta i prostornog rasporeda eolskog nanosa. Ukupan broj uzetih uzoraka za metodu praćenja količina 137Cs je iznosio 149, od kojih je bilo 9 inicijalnih uzoraka (3 profila po 3 uzorka), 14 osnovnih uzoraka (2 profila po 7 uzoraka), 32 ostala uzorka (8 profila po 4 uzorka), 36 referentnih uzoraka (9 profila po 4 uzorka) i 58 uzoraka uzetih zrakasto po određenim pravcima (N, NE, E, SE, S, SW, W, NW). Osnovni uzorak na neobrađenom zemljištu sa detektovanom količinom 137Cs od 10.603,57 Bq m-2 predstavlja uporednu vrednost, tj. lokalni padavinski ulaz 137Cs za modele pretvaranja količina 137Cs u količine izgubljenog zemljišta. Ovaj uzorak odslikava sredinu na kojoj su sprovedena istraživanja i predstavlja uporednu vrednost koja može korektno da definiše procese eolske erozije. Za pretvaranje izmerenih količina 137Cs u količine izgubljenog zemljišta po modelima Walling-a korišćen je najjednostavniji proporcionalni model (PM) za obrađena zemljišta, a najprimenjeniji model profilne distribucije (PDM) za neobrađena zemljišta u okviru najnovije verzije PC-kompatibilnog softverskog paketa u Microsoft Excel Add-Ins varijanti. Modelom profilne distribucije (PDM) za sve uzorake uzete na eksperimentalnom području dobijeni su prosečni gubici zemljišta od 207,06 t ha-1 god-1 i 2,10 cm. Model Basher & Webb je dao prosečne gubitke zemljišta od 212,18 t ha-1 god-1 i 2,09 cm. Gubici zemljišta dobijeni modelima pretvaranja količina 137Cs u količine izgubljenog zemljišta ukazuju na značajne procese eolske erozije definisane jakom i ekscesivnom eolskom erozijom. Za 58 uzoraka zemljišta uzetih na tačkama raspoređenih zrakasto po određenim pravcima (N, NE, E, SE, S, SW, W, NW), pored koncentracija i količina 137Cs i 210Pbex, određene su prostorne koordinate X i Y i nadmorske visine uzetih uzoraka. Prostorne distribucije koncentracija 137Cs i 210Pbex izražene su izolinijama, a kreiranani su i 3D prikazi u procentima odstupanja 137Cs i 210Pbex od lokalnog padavinskog ulaza 137Cs i 210Pbex. U oba slučaja je primetan dominantan uticaj pravca jugoistok - severozapad (SE-NW), odnosno jugoistočnog vetra „Košava”. Komparativna analiza ovih metoda je ukazala na validnost u kvantifikaciji procesa eolske erozije i mogućnost njihove primene u budućnosti, a dobijeni rezultati produkcije eolskog nanosa i gubitaka zemljišta su dali doprinos oceni stanja degradacije zemljišta i ugroženosti Deliblatske peščare. Erosion is a very complex physical process which, under the impact of atmospheric forces, creates destructive changes on the soil surface layer. In case the primary agent of particle movement is wind, we talk about wind or aeolian erosion. Aeolian erosion is a specific process which occurs in extremely complex situations of mutual interaction of numerous natural and anthropogenic factors of mainly stochastic properties making its research a complex scientific-research problem. The main goal of conducted research was to monitor the process of aeolian erosion at the chosen localities of Deliblato Sands, the largest and the most important area of the kind in Europe. In other words, the goal is to determine the quantities of aeolian sediment – sediment transport by direct systematic measurements in field conditions, determine dominant direction of sediment transport, define its annual distribution and determine the effect of vegetation on reducing the intensity of aeolian erosion. During a four-year period, for the first time in this area, i.e. at the same locality, a comparative research of aeolian erosion have been conducted using the mechanical sediment trap and activities based on 137Cs radioisotope tracing technique for estimating soil losses using special theoretical models. The monitoring of aeolian erosion processes was conducted during the period 2006 – 2009 at Cvijićev vis which was chosen as a typical locality since it was, apart from the central position on Deliblato Sands, a cultivated surface without any wind protection. Alongside with these measurements, at Dragićev hat – nursery garden, the monitoring of aeolian erosion was conducted on two measurement points during the period May 2006 – April 2007 in areas with the protective vegetative covers and/or vegetative belts. Aeolian erosion intensity measurement was performed by static sediment traps of the type “deflametre” (dimension of entry opening 10 x 10 cm) oriented on certain directions (N, NE, E, SE, S, SW, W, NW) in order to define the aeolian erosion processes in vector terms. The quantification of aeolian sediment using static traps constantly facing certain wind blowing directions enabled to log and differentiate “summary” yield of aeolian sediment (arithmetic sum of all sediment quantities from all traps) and “resulting” quantity of aeolian sediment (vector sum), since those quantities determine not only the entire amount of transported aeolian sediment (sediment yield) but also the sediment transported outside the areas of erosion field (soil loss), bur also the general direction of its transport. Aeolian erosion measurement on Cvijićev vis for the period 2006 – 2009 indicated the significant aeolian erosion processes which were defined by medium annual ediment transport of 4.48 kg m-1. It has been determined that the total quantities of moved sediment were 25.94, 20.92, 52.98 and 43.47 kg m-1 year-1, and sediment transport 3.24, 2.61, 6.62 and 5.43 kg m-1 year-1 in 2006, 2007, 2008 and 2009 respectively. Sediment transport for the period May 2006 – April 2007 showed that on Cvijićev vis which is characterized by bareness and openness there was the biggest aeolian erosion – four times bigger compared to Dragićev hat – nursery garden I characterized by bareness and protectiveness and 30.2 times bigger compared to Dragićev hat – nursery garden II characterized by overgrown condition and protectiveness of erosive field. At the locality Dragićev hat – nursery garden I the aeolian erosion was recorded 7.5 times bigger compared to the one recorded on Dragićev hat – nursery garden II. Soil loses expressed through the resulting monthly sediment transport (vector sum) equalled 5.13, 2.04, 4.31 and 11.94 kg m-1 in 2006, 2007, 2008 and 2009 respectively, and the percentage share of annual soil losses compared to total sediment yield (arithmetical sum) varied between 8.1% and 27.5%. The resulting aeolian sediment movement direction was SE-NW under the influence of the dominant southeast wind “Koshava”. Even though the most reliable determination of aeolian erosion and its effects is based on direct systematic measurements in real time conditions in the field, starting from the end of the last century the methods of tracking radionuclide from radioactive precipitation, especially 137Cs, for the purposes of estimating the soil loss and spatial distribution of aeolian sediment, have been used increasingly. The total number of samples taken for the method of monitoring the quantity of 137Cs was 149, 9 of which were initial samples (3 profiles with 3 samples each), 14 main samples (2 profiles with 7 samples each), 32 remaining samples (8 profiles with 4 samples each), 36 reference samples (9 profiles with 4 samples each) and 58 samples taken radially on certain directions (N, NE, E, SE, S, SW, W, NW). The main sample taken from the uncultivated land with the detected quantity of 137Cs of 10,603.57 Bq m-2 represents the comparative value, i.e. local precipitation input of 137Cs for the models of 137Cs quantities conversion into the quantities of lost soil. This sample depicts the area where the research was conducted and represents the comparative value which can properly define the aeolian erosion processes. For converting the measured quantities of 137Cs into the quantities of lost soil using Walling model the simplest proportional model (PM) for cultivated land was used and the most appropriate profile distribution model (PDM) for uncultivated soil with the newest version of PC compatible software package in Microsoft Excel Add-Ins. Using the profile distribution model (PDM) on all samples taken from the experimental area the quantities of average soil loss obtained were 207.06 t ha-1 year-1 and 2.10 cm. Basher & Webb model gave the average soil loss of 212.18 t ha-1 year-1 and 2.09 cm. Soil loss calculated using the conversion of 137Cs quantities into the soil loss quantities indicate the significant aeolian processes defined by strong and excessive aeolian erosion. For 58 soil samples taken from areas radially distributed on certain directions (N, NE, E, SE, S, SW, W, NW), apart from 137Cs and 210Pbex concentrations and quantities, spatial coordinates X and Y were determined as well as the altitude of taken samples. Spatial distribution of 137Cs and 210Pbex quantities are represented by isolines, and also 3D demonstrations were created showing the percentage of deviation of 137Cs and 210Pbex from the local precipitation input of 137Cs and 210Pbex. In both cases, the dominant direction SENW was noticeable, i.e. the southeast wind “Koshava”. The comparative analysis of these methods indicated the validity in the quantification of aeolian erosion process and the possibility of its application in the future and the obtained results of aeolian sediment yield and soil loss contributed to determining the state of soil degradation and vulnerability of Deliblato Sands
The Effect of Irrigation Treatments and Sowing Periods on Water Use Efficiency, Yield and Quality of Common Bean
Full text linkавремено друштво се сусреће са врло озбиљним изазовима у пољопривредној
производњи, а везано за све веће захтеве за храном као и недостатком воде у овом сектору.
Полазећи од ових чињеница, истраживање које је описано у овој дисертације је првенствено
посвећено рационалном коришћењу водних ресурса и проналажењу начина како повећати
производњу хране.
Циљ ове докторске дисертације био је да се испита утицај режима наводњавања и рока
сетве на ефикасност коришћења воде, принос и квалитет зрна пасуља. Истраживање је
вршено на пасуљу сорте сремац. Постављен је двофакторијални оглед по split plot плану
(плану подељених парцела) у три понављања. Први фактор (парцела) био је рок сетве: сетва
у редовном року, половином априла (I) и две касне сетве (крај маја/почетак јуна (II) и крај
јуна/почетак јула (III)). Други фактор (подпарцела) био је режим наводњавања (третман
пуног наводњавања (Ф) и два третмана редукованог наводњавања (Д1 и Д2)). Трогодишње
истраживање у периоду од половине априла до почетка октобра (2018, 2019. и 2020. године)
извршено је на огледном пољу компаније „Напредак“ а. д. Стара Пазова. Све три године биле
су веома топле, али истовремено и веома кишне. Сума падавина током истраживаног
периода варирала је од 590 mm (2019) до 434 mm (2020) године, што је далеко изнад
просечне вредности за овај период која износи 359 mm.
У оквиру испитиваних фактора (рок сетве и режим наводњавања) праћена је фенологија
пасуља, влажност земљишта, покровност земљишта, акумулација суве биомасе, индекс лисне
површине, потрошња воде пасуља, стање вегетације и снабдевеност водом, принос пасуља,
принос суве биомасе, број махуна по биљци, маса 1000 зрна, жетвени индекс, хемијске
особине зрна пасуља (садржај протеина и уља), као и продуктивност воде и ефикасност
коришћења воде. У раду су, поред осталих, примењене савремене методе даљинске детекције
(мултиспектрални и термални снимци).
Највеће вредности садржаја воде у земљишту регистроване су у оквиру Ф третмана у
свим испитиваним роковима сетве, и овај садржај воде није се спуштао испод границе лако
приступачне воде биљкама, изузев током сазревања. Режим пуног наводњавања (Ф)
остварио је значајно већу (p<0,05) акумулацију биомасе и проценат покровности земљишта у
поређењу са Д2 третманом, док се третман Д1 није значајно разликовао.
Режим наводњавања и рокови сетве испољили су статистичку значајност на промену
вредности стварне евапотранспирације. Утврђена је разлика у просечним вредностима
стварне евапотранспирације између третмана наводњавања и између појединих рокова сетви.
У трогодишњем периоду у првом року сетве у просеку је трошено 383,4 mm, у другом 407,9
mm а у трећем 360,0 mm. На варијанти са пуним наводњавањем у просеку је потрошено
401,7 mm, док је потрошња воде на третманима редукованог заливања мања у односу на Ф
третмане (383,1 mm и 366,9 mm на третманима Д1 и Д2, редом).
Израчунати вегетациони индекси (NDVI - вегетациони индекс нормализоване разлике;
GNDVI - зелени вегетациони индекс нормализоване разлике; MCARI1 - модификовани
индекс абсорпције хлорофила у рефлексији) добијени су на основу мултиспектралних
снимака беспилотном летелицом (дроном). Вредности NDVI, MCARI1 и GNDVI су
статистички значајно више у Ф третману него на третманима редукованог наводњавања.
Вегетациони индекси NDVI, MCARI1, и GNDVI били су у доброј до јакој корелацији са
величинама на које утиче режим наводњавања: покривеношћу, индексом лисне површине и
транспирацијом, али и у задовољавајућој корелацији са вредностима влажности земљишта...Modern society is facing serious challenges in agricultural production related to increasing
food demand and water scarcity. Based on these facts, the research described in this dissertation is
primarily dedicated to the rational use of water resources and finding ways to ramp up food
production.
The aim of this doctoral dissertation was to examine the impact of irrigation regimes and
sowing periods on water use efficiency, yield, and grain quality of beans, specifically the sremac
bean variety. The research was conducted in a two-factorial trial using a split-plot design divided
into three repetitions. The first factor (plot) was the sowing period, including sowing in the regular
term, mid-April (I) and two late sowings (end of May/beginning of June (II) and end of
June/beginning of July (III)). The second factor (subplot) was the irrigation regime, which included
full irrigation treatment (F) and two deficit irrigation treatments (D1 and D2). The three-year study
was conducted from mid-April to early October (2018, 2019, 2020) on the experimental field of the
company "Napredak" a.d. Stara Pazova. All three years were warm and rainy, with total
precipitation during the study period ranging from 590 mm (2019) to 434 mm (2020), which is well
above the average value of 359 mm for this period.
Within the framework of the examined factors (sowing period and irrigation regime), the
following aspects were monitored: phenology of beans, soil moisture, canopy cover, dry biomass
accumulation, leaf area index, water consumption of common bean, plant health and water status,
grain yield, dry biomass yield, number of pods per plant, 1000-grain weight, harvest index,
chemical properties of bean grains (protein and oil content), and water productivity and water use
efficiency. The research also applied modern remote sensing methods, including multispectral and
thermal images.
The highest soil moisture was observed in the F treatment (full irrigation) during all three
sowing periods and water content did not drop below the readily avaliable water level, except
during maturation. The full irrigation regime (F) achieved significantly higher (p<0.05) biomass
accumulation and canopy cover compared to the D2 treatment, while the D1 did not differ
significantly.
The effect of the irrigation regime and sowing period was statistically significant in changing
the values of actual evapotranspiration. The difference in average values of actual
evapotranspiration between irrigation treatments and between sowing periods was determined. In
the three-year period, an average of 383.4 mm was spent in the first sowing period, 407.9 mm in the
second, and 360.0 mm in the third. In the full irrigation treatment, an average of 401.7 mm was
consumed, while water consumption in deficit irrigation treatments was lower compared to the F
treatment (381.1 mm and 366.9 mm in the D1 and D2 treatments, respectively)
Calculated vegetation indices (NDVI - normalized difference vegetation index, GNDVI -
green normalized difference vegetation index, and MCARI1 - modified chlorophyll absorption ratio
index at 700 nm) were obtained from multispectral images taken by an unmanned aerial vehicle
(drone). The values of NDVI, MCARI1 and GNDVI were significantly higher in the F treatment than
in the deficit irrigation treatments. Vegetation indices NDVI, MCARI1, and GNDVI were in good to
strong correlation with the variables affected by the irrigation regime: canopy cover, leaf area index
and transpiration, as well as satisfactory correlation with soil moisture values. The high correlations
of the NDVI, MCARI1 and GNDVI indices with the detection of differences in irrigation regimes
qualify them as a reliable tools for estimating bean yields..
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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