Determination of pesticide residues in watermelons by LC-MS/MS

The LC–MS/MS was applied for the detection of pesticide residues in watermelons. Since watermelons are predominantly used as fresh food and to a lesser extent in food processing there is a justified concern that, due to treatments, they can contain pesticide residues above the maximum residue levels – MRLs. The pesticide extraction was carried out by QuEChERS method. The samples were tested regarding the content of 55 pesticides with the carbofuran-D3 as internal standard. The linearity was studied in the range of 0.01–0.50 mg/kg and the determination coefficients (R2) were higher than 0.99 for all the investigated pesticides. The calibration was performed as matrix calibration, by means of spiking the calibration samples before the extraction and preparing them in the same way as the test samples. The recovery data were obtained by spiking blank samples at three concentration levels (0.01, 0.05 and 0.1 mg/kg) yielding recoveries in the range of 61.0–114.2% with the relative standard deviation (RSD) less than 13%. The limits of quantification (LOQs) were established as 0.01 mg/kg. The multiple detections were confirmed in the analysed samples. The most frequently detected pesticides were carbendazim, acetamiprid, tefluthrin and fenpropimorph. In only one sample the concentrations of carbendazim and tefluthrin were above the MRLs

Efficiency of different methods and forms of microelements application in function of n fertilizer in apple trees

In order to achieve a high yield and quality of apple fruit, more effective ways of fertilization are required in the modern, high density apple orchards. The objective of this research was to determine the efficiency (partial nutrient balance, PNB) of different methods (foliar and fertrigation) and forms (chelates and salts) of microelements application in relation to the levels of N fertilization in apple orchard cultivar (‘Golden Delicious’). The combined effects of these fertilizers on the number of apple fruits per tree and on the yield per tree were also studied. Foliar application of Mn, Zn and Fe had significantly higher partial nutrient balance values compared to the soil application in both years of the experiment. However, most of the PNB values were below 10% indicating relatively low efficiency of the applied fertilizers with microelements

Annual legumes as green manure crops

There is a large number of annual legume species having an economic importance either on a world or local scale, such as pea (Pisum sativum L.), faba bean (Vicia faba L.), lentil (Lens culinaris Medik.), grass pea (Lathyrus sativus L.) and vetches (Vicia spp.). All these crops are multi-functional and are used for both human consumption and in animal feeding. Apart from these various food and feed uses, annual legumes may represent a quality green manure, playing one of the most significant roles in organic farming and sustainable agriculture. In addition to their ability to increase soil fertility by a symbiosis with nitrogen-fixation bacteria, annual legumes are able to produce a considerable amount of aboveground biomass, also rich in nitrogen. For instance, aboveground biomass nitrogen yield in grass pea may surpass 300 kg ha-1, while in lentil it is higher than 100 kg ha-1

Vermicompost and Vermicompost Leachate Application in Strawberry Production: Impact on Yield and Fruit Quality

Recycling organic waste is most important for preserving natural resources. The research objective was to quantify the effect of the application of vermicompost and vermicompost leachate on the yield and quality of strawberries and compare it with a standard fertilization program with mineral fertilizers during a 3-year production cycle. Five fertilization treatments were studied: control—without fertilizer (Ø); vermicompost (V); vermicompost + foliar application of vermicompost leachate (VL); vermicompost leachate through fertigation and foliar application (L); and mineral NPK fertilizers (NPK). The application of V positively affected strawberry yield only in the first year. In all three years of fruiting, the highest yield was measured for NPK treatment. In the first year, fertilization had no effect on fruit quality, while in the second and third years, the application of leachate led to a significantly higher concentration of total soluble solids, total anthocyanins, antioxidant activity of the fruit, and a lower concentration of total acid. Strawberries are grown for a two- or three-year production cycle, so the application of V and VL cannot maintain the yield level as was with the application of mineral NPK fertilizers. The quality of strawberry fruit, however, can be improved significantly

Application of organic fertilizers TI in strawberry production

Органска ђубрива садрже готово све неопходне хранљиве елементе за гајене биљке, али имају значајно мању ефикасност од синтетичких ђубрива јер је садржај хранива неупоредиво нижи у односу на синтетичка, а облици у којима се налазе нису директно приступачни гајеним биљкама. Циљ истраживања био је да се испита утицај примене различитих органских ђубрива биљног и животињског порекла, као и течних ђубрива на хемијска својства земљишта, принос и квалитет јагоде у оквиру два система производње (малчирања земљишта). Пољски оглед је постављен као двофакторијални по методи/плану подељених парцела (Split/plot), са случајним распоредом третмана. Оглед се састојао од две главне парцеле на којима је испитан утицај два различита начина покривања земљишта (малч од сламе и црна полиетиленска фолија), док је на основним парцелама испитан утицај 13 различитих третмана ђубрења (контрола – без примене ђубрива, Ø; говеђи стајњак, С; говеђи стајњак + гуано (фолијарно), С+Г; говеђи стајњак + екстакт глистењака (фолијарно), С+ЕГ; глистењак, ГЛ; глистењак + гуано (фолијарно), ГЛ+Г; глистењак + екстракт глистењака (фолијарно), ГЛ+ЕГ; компост из производње печурака, К; компост из производње печурака + гуано (фолијарно), К+Г; компост из производње печурака + екстракт глистењака, К+ЕГ; гуано (фертигација + фолијарно), Г; екстракт глистењака (фертигација + фолијарно), ЕГ; стандардни програм ђубрења са минералним NPK ђубривима, NPK). У узорцима земљишта одређен је садржај минералних облика N, приступачних облика P, K, Ca, Mg, Fe, Mn, Cu, Zn и pH вредност земљишта. Поред параметара приноса јагоде (број цветова, прој плодова, просечна маса плода) у све три године плодоношења одређени су садржај макро и микроелемената у листу и плоду јагоде, и параметри квалитета плода јагоде (укупан садржај растворљиве суве материје, укупан садржај киселина, садржај укупних антоцијана, антиоксидативна активност, обојеност и чврстина плода). Резултати истраживања су показали да се продужено дејство примене чврстих и течних органских ђубрива на садржај хранљивих елемената у земљишту значајно разликује у зависности од елемента који се посматра. Примена чврстих органских ђубрива имала је највећи утицај на садржај приступачних облика фосфора, затим калијума, док је најмањи утицај имала на садржај минералних облика азота у земљишту. Изузев стајњака, примена органских ђубрива, у количини еквивалентној 170 kg N ha-1, није имала утицај на концентрацију приступачних облика секундарних макроелемената и микроелемената у земљишту. Земљиште покривено црном ПЕ фолијом одликовало се вишим садржајем минералних облика азота и приступачних облика Fe, Mn, Zn и Cu у односу на земљиште покривено сламом, у свим терминима мерења. Примена чврстих органских ђубрива приликом садње јагоде довела је до значајног повећања приноса, у односу на контролу, само у првој години плодоношења, док је у другој и трећој години плодоношења највиши принос јагоде остварен на третманима где су примењена NPK ђубрива и течни гуано. Третмани ђубрења имали су значајан утицај на минерални састав, садржај растворљиве суве материје, садржај киселина, садржај антоцијана, антиоксидативну активност и обојеност плода. Примена црне полиетиленске фолије, поред позитивног утицаја на садржај хранљивих елемената у земљишту, довела је до вишег приноса и квалитета плода јагоде у односу на примену сламе као малча. Rезултати показују да се применом црне фолије може значајно повећати ефикасност ђубрива чиме се смањује ризик од загађења животне средине и остварује већа економска добит у производњи јагоде.Organska đubriva sadrže gotovo sve neophodne hranljive elemente za gajene biljke, ali imaju značajno manju efikasnost od sintetičkih đubriva jer je sadržaj hraniva neuporedivo niži u odnosu na sintetička, a oblici u kojima se nalaze nisu direktno pristupačni gajenim biljkama. Cilj istraživanja bio je da se ispita uticaj primene različitih organskih đubriva biljnog i životinjskog porekla, kao i tečnih đubriva na hemijska svojstva zemljišta, prinos i kvalitet jagode u okviru dva sistema proizvodnje (malčiranja zemljišta). Poljski ogled je postavljen kao dvofaktorijalni po metodi/planu podeljenih parcela (Split/plot), sa slučajnim rasporedom tretmana. Ogled se sastojao od dve glavne parcele na kojima je ispitan uticaj dva različita načina pokrivanja zemljišta (malč od slame i crna polietilenska folija), dok je na osnovnim parcelama ispitan uticaj 13 različitih tretmana đubrenja (kontrola – bez primene đubriva, Ø; goveđi stajnjak, S; goveđi stajnjak + guano (folijarno), S+G; goveđi stajnjak + ekstakt glistenjaka (folijarno), S+EG; glistenjak, GL; glistenjak + guano (folijarno), GL+G; glistenjak + ekstrakt glistenjaka (folijarno), GL+EG; kompost iz proizvodnje pečuraka, K; kompost iz proizvodnje pečuraka + guano (folijarno), K+G; kompost iz proizvodnje pečuraka + ekstrakt glistenjaka, K+EG; guano (fertigacija + folijarno), G; ekstrakt glistenjaka (fertigacija + folijarno), EG; standardni program đubrenja sa mineralnim NPK đubrivima, NPK). U uzorcima zemljišta određen je sadržaj mineralnih oblika N, pristupačnih oblika P, K, Ca, Mg, Fe, Mn, Cu, Zn i pH vrednost zemljišta. Pored parametara prinosa jagode (broj cvetova, proj plodova, prosečna masa ploda) u sve tri godine plodonošenja određeni su sadržaj makro i mikroelemenata u listu i plodu jagode, i parametri kvaliteta ploda jagode (ukupan sadržaj rastvorljive suve materije, ukupan sadržaj kiselina, sadržaj ukupnih antocijana, antioksidativna aktivnost, obojenost i čvrstina ploda). Rezultati istraživanja su pokazali da se produženo dejstvo primene čvrstih i tečnih organskih đubriva na sadržaj hranljivih elemenata u zemljištu značajno razlikuje u zavisnosti od elementa koji se posmatra. Primena čvrstih organskih đubriva imala je najveći uticaj na sadržaj pristupačnih oblika fosfora, zatim kalijuma, dok je najmanji uticaj imala na sadržaj mineralnih oblika azota u zemljištu. Izuzev stajnjaka, primena organskih đubriva, u količini ekvivalentnoj 170 kg N ha-1, nije imala uticaj na koncentraciju pristupačnih oblika sekundarnih makroelemenata i mikroelemenata u zemljištu. Zemljište pokriveno crnom PE folijom odlikovalo se višim sadržajem mineralnih oblika azota i pristupačnih oblika Fe, Mn, Zn i Cu u odnosu na zemljište pokriveno slamom, u svim terminima merenja. Primena čvrstih organskih đubriva prilikom sadnje jagode dovela je do značajnog povećanja prinosa, u odnosu na kontrolu, samo u prvoj godini plodonošenja, dok je u drugoj i trećoj godini plodonošenja najviši prinos jagode ostvaren na tretmanima gde su primenjena NPK đubriva i tečni guano. Tretmani đubrenja imali su značajan uticaj na mineralni sastav, sadržaj rastvorljive suve materije, sadržaj kiselina, sadržaj antocijana, antioksidativnu aktivnost i obojenost ploda. Primena crne polietilenske folije, pored pozitivnog uticaja na sadržaj hranljivih elemenata u zemljištu, dovela je do višeg prinosa i kvaliteta ploda jagode u odnosu na primenu slame kao malča. Rezultati pokazuju da se primenom crne folije može značajno povećati efikasnost đubriva čime se smanjuje rizik od zagađenja životne sredine i ostvaruje veća ekonomska dobit u proizvodnji jagode.Organic fertilizers contain almost all the necessary nutritional elements for cultivated plants, but they have a significantly lower efficiency compared to synthetic fertilizers due to lower nutrient content and the forms of nutrients in which they are not directly accessible to the cultivated plants. The aim of this study was to quantify the effect of the application of different plant and animal origin organic fertilizer, as well as liquid fertilizers, on soil chemical properties, yield and quality of strawberries in two production systems (soil mulching). The field experiment was conducted using a 2-factorial split-plot completely randomized design, with ground cover management (mulch) as main-plot factor and fertilization treatments in sub-plot. On the main plots we examined the influence of two different mulches (straw and black polyethylene sheet), while on sub-plots the effect of 13 different treatments of fertilization was examined (control - no fertilization, Ø; dairy manure, С; dairy manure + guano (foliar application), С+Г; dairy manure + vermicompost leachate (foliar application), С+ЕГ; vermicompost, ГЛ; vermicompost leachate + guano (foliar application), ГЛ+Г; vermicompost + vermicompost leachate (foliar application), ГЛ+ЕГ; spent mushroom compost, К; spent mushroom compost + guano (foliar application), К+Г; spent mushroom compost + vermicompost leachate, К+ЕГ; guano (fertigation + foliar application), Г; vermicompost leachate (fertigation + foliar application), ЕГ; standard fertilization with mineral NPK fertilizers, NPK). The soil samples were analysed to determine the content of mineral forms of N, available forms of P, K, Ca, Mg, Fe, Mn, Cu, Zn and soil pH value. Beside parameters of strawberry yield (number of flowers, number of fruits, average fruit weight) in all three fruiting years we determined the content of macro- and microelements in the leaves and fruits, as well as fruit quality parameters (total soluble solids, total acidity, total anthocyanins, antioxidant activity, coloring and fruit firmness). The results showed that application of solid and liquid organic fertilizers had a different residual effect on concentration of macro- and micro elements in the soil. Application of solid organic fertilizer had the greatest influence on the content of available forms of phosphorus, than potassium, while the least impact had on the content of mineral forms of nitrogen in the soil. Except for dairy manure, the application of organic fertilizers, in amount equivalent to 170 kg N ha-1, had no effect on concentration of available forms of secondary macroelements and microelements in the soil. Soil covered with black polyethylene mulch had higher content of mineral forms of nitrogen and available forms of Fe, Mn, Zn and Cu, compared to soil covered with straw mulch, in all terms of measuring. The application of solid organic fertilizers led to a significant increase in yield compared to the control in the first fruiting year, while in the second and third fruiting years the highest yields were achieved on the treatments where NPK fertilizer and liquid guano were applied. Fertilization treatments had a significant effect on the mineral composition, content of soluble solids, titrible acidity, content of anthocyanins, antioxidant activity and color of the strawberry fruits. Black polyethylene mulch had positive impact on concentration of macro- and microelements in soil and led to higher yield and quality of strawberry fruits compared to straw mulch. The results shows that the black polyethylene mulch can significantly increase fertilizer efficiency, which reduce the risk of environmental pollution and may result in greater economic gain in strawberry production

Nitrogen Mineralization And Carbon Dynamic In Soil Affected By Biogas Residues

The aims of the study were to investigate the N mineralization potential and C status in the incubation experiment after application of digestates (solid and liquid) to the soil, and to compare with the impact of manures (solid and liquid). Biogas residues and manures were collected from three random bioenergy production systems, using cattle manure as the main substrate, and other substrates are residues from sugar and oil industry, corn and wheat silage, etc. The results show that all applied digestates and liquid manure increased NH4–N and NO3–N in soil at the beginning of the incubation. However, at the end of the 56 days of incubation, except two liquid digestates, studied organic materials led to immobilization of mineral N in soil

Digestate and Manure Use in Kohlrabi Production: Impact on Plant-Available Nutrients and Heavy Metals in Soil, Yield, and Mineral Composition

Digestate is a residue of the anaerobic decomposition of organic waste for biogas extraction, but it can be reused as a source of nutrients. To examine the effect of digestate in kohlrabi production, field experiments were conducted during three seasons in two calendar years. The fertilization treatments included the application of solid digestate (two rates—DS1 and DS2), liquid digestate (two rates—DL1 and DL2), solid manure (two rates—MS1 and MS2), and mineral fertilizer (NPK) and were compared with a plot without fertilization (Ø). The results showed a significant increase in the yield with the use of solid and liquid digestate, as well as with NPK, in all growing seasons, while the microelement contents (Zn, Mn, and Cu) in the leaves were at optimum level. The applied treatments did not increase the plant-available nutrients (AL-P2O5, AL-K2O, Fe, Cu, and Zn) in the soil (except Mn). The application of DL2, MS1, and MS2 led to a higher Pb content in kohlrabi stems compared to the control, but the Pb content remained below the maximum permitted limit. Our research showed that digestate can be used as a valuable source of nutrients for kohlrabi production, with a low risk of soil and plant contamination by heavy metals. However, the control of soil, digestates, and manure quality is recommended

Digestate and Manure Use in Kohlrabi Production: Impact on Plant-Available Nutrients and Heavy Metals in Soil, Yield, and Mineral Composition

Digestate is a residue of the anaerobic decomposition of organic waste for biogas extraction, but it can be reused as a source of nutrients. To examine the effect of digestate in kohlrabi production, field experiments were conducted during three seasons in two calendar years. The fertilization treatments included the application of solid digestate (two rates—DS1 and DS2), liquid digestate (two rates—DL1 and DL2), solid manure (two rates—MS1 and MS2), and mineral fertilizer (NPK) and were compared with a plot without fertilization (Ø). The results showed a significant increase in the yield with the use of solid and liquid digestate, as well as with NPK, in all growing seasons, while the microelement contents (Zn, Mn, and Cu) in the leaves were at optimum level. The applied treatments did not increase the plant-available nutrients (AL-P2O5, AL-K2O, Fe, Cu, and Zn) in the soil (except Mn). The application of DL2, MS1, and MS2 led to a higher Pb content in kohlrabi stems compared to the control, but the Pb content remained below the maximum permitted limit. Our research showed that digestate can be used as a valuable source of nutrients for kohlrabi production, with a low risk of soil and plant contamination by heavy metals. However, the control of soil, digestates, and manure quality is recommended

Performance of legume–grass mixtures in the West Balkan region

Three perennial legumes (alfalfa, red clover and birdsfoot trefoil) and four cool-season perennial grasses (orchardgrass, tall fescue, Italian ryegrass and red fescue) were grown in legume–grass combinations and in pure stands of individual species, at three locations in the West Balkan region (Novi Sad, Banja Luka and Pristina) in the period from 2012 to 2015. The study evaluated dry matter yield, legume–grass–weed proportion and forage quality. High annual forage yield of legume–grass mixtures can be obtained with proper selection of species and an appropriate legume–grass ratio. However, high and stable yield, particularly in the case of grasses, depends on the amount and schedule of precipitation as well as the cutting time. The mixtures and legume pure stands achieved better forage production both per cutting and on the annual basis and had better forage quality than grass pure stands