| Abstract | Svaka sorta ili hibrid neke ratarske kulture ima različite zahtjeve prema ekološkim
uvjetima i svojstvima tla, a zahtjeva i određene specifičnosti u tehnologiji proizvodnje.
Unatoč poznatoj činjenici kako uljana repica za visoke prinose treba velike količine dušika
koji je i najveći input, malo je znanstvenih istraživanja u nama dostupnoj literaturi koja
proučavaju utjecaj gnojidbe dušikom na agronomska i energetska svojstva uljane repice.
Nakon žetve uljane repice ostaje velika količina stabljike koja se može iskoristiti kao
sirovina za proizvodnju biogoriva. Za razliku od uljane repice, pir zahtjeva znatno manjeuljana repica, pir, sorta, gnojidba dušikom, prinos, agronomska svojstva,
energetska svojstva
dušika, a stvara veću količinu biomase (slama i pljeve), stoga je pogodan kao sirovina za
proizvodnju energije. Optimizacija gnojidbe dušikom kod svih kultura pa tako i uljane
repice i pira mora balansirati odnos između prinosa i kvalitete sirovine bilo da se radi o
sjemenu ili zrnu, odnosno biomasi, uz istovremenu zaštitu okoliša. Zbog svega
navedenog, cilj ovog istraživanja bio je utvrditi agronomska svojstva uljane repice i pira s
obzirom na izbor sorte/hibrida i prihranu različitim količinama dušika te utvrditi energetska
svojstva biomase kao sirovine za proizvodnju toplinske i/ili električne energije s obzirom
na izbor kulture, sorte i različite gnojidbe dušikom. Istraživanja su provedena kroz poljske
pokuse postavljene na antropogeniziranom, eutrično smeđem tlu u agroekološkim
uvjetima sjeverozapadne Hrvatske na pokušalištu Sveučilišta u Zagrebu Agronomskog
fakulteta u dvije vegetacijske godine za svaku kulturu.
U 2012./2013. i 2013./2014. godini istraživana su tri različita genotipa uljane repice
(konvencionalni hibrid SY Cassidy, sorta Komando i polupatuljasti hibrid PR45D03) i tri
varijante prihrane dušikom koje uključuju zalihu mineralnog dušika u tlu: N1 - bez
prihrane, N2 - razliku dušika iz gnojiva do 150 kg ha-1 dušika u tlu u jednoj prihrani i N3 -
razliku dušika iz gnojiva do 200 kg ha-1 dušika u tlu primijenjenu u dvije prihrane (60 % u
fazi BBCH 30 + 40 % u fazi BBCH 39). U 2012./2013. godini zaliha mineralnog dušika u
tlu iznosila je 77 kg ha-1 te je u prvoj prihrani uljane repice primijenjeno 73 kg ha-1 dušika
(N2), a u drugoj prihrani još 50 kg ha-1 dušika čime je gnojivom dodano ukupno
123 kg ha-1 dušika (N3). U 2013./2014. godini zaliha mineralnog dušika u tlu iznosila je
60 kg ha-1, stoga je u prvoj prihrani uljane repice primijenjeno 90 kg ha-1 dušika (N2), a u
drugoj prihrani još 50 kg ha-1 čime je gnojivom dodano ukupno 140 kg ha-1 dušika (N3).
U 2013./2014. i 2014./2015. godini istraživane su tri sorte pira (Nirvana, Ostro i Bc Vigor) i
tri varijante prihrane dušikom: N1 - bez prihrane, N2 - 25 kg ha-1 dušika u jednoj prihrani i
N3 - 50 kg ha-1 dušika u dvije prihrane (25 kg ha-1 N u početku vegetacije u proljeće + 25
kg ha-1 N na kraju busanja).
U obje godine istraživanja utvrđene su značajne razlike između istraživane sorte i hibrida
uljane repice u prinosu sjemena i ulja. Značajno najveći prinos sjemena i ulja ostvario je
konvencionalni hibrid SY Cassidy. U 2012./2013. godini najveći prinos stabljike i praznih
komuški ostvarili su konvencionalni hibrid SY Cassidy i sorta Komando.
Povećanjem količine dušika, tj. primjenom 90 kg ha-1 dušika u jednoj prihrani (N2)
značajno je povećan prinos sjemena, a primjenom 140 kg ha-1 dušika u dvije prihrane
(N3) povećan je prinos stabljike i praznih komuški, ali samo u izrazito vlažnoj 2013./2014.
godini.
Istraživane sorte pira značajno su se razlikovale u prinosu oljuštenog zrna i žetvenom
indeksu. Signifikantno najveći prinos oljuštenog zrna i najveći žetveni indeks utvrđen je
kod sorte Nirvana. U 2014./2015. godini značajno najveći prinos slame utvrđen je kod
sorti Bc Vigor i Ostro, a najmanji udio pljeva i pljevica kod sorte Nirvana.
Povećanjem količine dušika, tj. primjenom 25 kg ha-1 dušika u prvoj prihrani (N2) značajno
je povećan prinos neoljuštenog i oljuštenog zrna pira i prinos pljeva i pljevica u
2014./2015. godini te prinos slame, ali samo u vlažnoj 2013./2014. godini.
Rezultati laboratorijskih istraživanja su pokazali kako slama pira ima veću donju ogrjevnu
vrijednost (17,03 MJ kg-1) nego stabljike uljane repice (16,57 MJ kg-1) jer sadrži viši udio
ugljika, koksa i fiksiranog ugljika, a niži udio kisika, hlapivih tvari i dušika. Slama pira u
odnosu na stabljiku uljane repice sadrži niži udio sumpora.
Najpovoljnija energetska svojstva stabljike uljane repice utvrđena su kod konvencionalnog
hibrida SY Cassidy i sorte Komando.
Prihrana većim količinama dušika uglavnom je pozitivno utjecala na energetska svojstva
biomase, tj. stabljike uljane repice kroz povećanje udjela vodika i koksa te smanjenja
udjela hlapivih tvari.
Istraživane sorte pira nisu se značajno razlikovale u energetskim svojstvima slame kao
biomase, osim u 2014./2015. godini kada je značajno najmanji udio pepela u slami
utvrđen kod sorte Nirvana.
Prihrana dušikom uglavnom je pozitivno utjecala na energetska svojstva slame pira kroz
povećanje udjela ugljika i smanjenja udjela kisika i pepela, ali i negativno zbog smanjenja
udjela koksa i povećanja udjela dušika.
U prosjeku istraživanja, slama pira je ostvarila veći prinos iskoristive biomase
(2.492 kg ha-1) i energetski prinos (42.455 MJ ha-1) u odnosu na stabljiku uljane repice
(2.235 kg ha-1, odnosno 37.037 MJ ha-1). |
| Abstract (english) | Each cultivar or hybrid has different requirements according to environmental conditions
and soil properties and requires certain specifics in the production technology. Despite the
well known fact that rapeseed for high yields should have large amounts of nitrogen,
which is the biggest input, there are little scientific researches into the available literature
to study of nitrogen fertilization effect on the agronomic and energetic traits of the
rapeseed. After rapeseed harvest there are a large quantity of stalks on field that can be
used as raw material for biofuels production. In contrast to rapeseed, spelt requires
significantly less nitrogen and produces a larger quantity of biomass (straw and glumes)
compared to other cereals and is also suitable as raw materials for energy production.
Optimization of nitrogen fertilization for all crops, including rapeseed and spelt, must
balance the relationship between the yield and quality of feedstock whether it is a seed or
grain or biomass, with concurrently protecting the environment. Consequently, the aim of
this study was to determine the agronomic traits of rapeseed and spelt, with regard to the
selection of cultivar and fertilization with different nitrogen rate and determine the
energetic traits of biomass as a feedstock for production heat and/or electricity in the
selection of culture, cultivar and different nitrogen fertilization.
Research was carried out through laboratory and field experiments placed on
anthropogenic, eutric brown soil in the environmental conditions of northwestern Croatia.
Research was placed on the University of Zagreb, Faculty of Agriculture experimental field
throught two growing seasons for each crop. In 2012/2013 and 2013/2014 year were
researched three different genotypes of rapeseed (conventional hybrid SY Cassidy,
cultivar Komando and semi-dwarf hybrid PR45D03) and three variants of nitrogen
topdressing. In nitrogen topdressing variants were included soil mineral nitrogen supply.
Variants of nitrogen topdressing was: N1 - without topdressing, N2 - a difference from
nitrogen fertilizers to 150 kg ha-1 of nitrogen in the soil in one application and N3 - the
difference of nitrogen fertilizer to 200 kg ha-1 of nitrogen in the soil applied in two
topdressing (60 % in stage BBCH 30 + 40% at the stage BBCH 39). In 2012/2013 year
soil mineral nitrogen supply was 77 kg ha-1 and in the first rapeseed topdressing was
applied 73 kg ha-1 of nitrogen (N2), in the second topdressing another 50 kg ha-1 of
nitrogen fertilizer, which has added a total 123 kg ha-1 of nitrogen (N3). In 2013/2014 year
soil mineral nitrogen supply was 60 kg ha-1, therefore, in the first topdressing was applied
90 kg ha-1 of nitrogen fertilizer (N2), in the second topdressing another 50 kg ha-1, in which
is applied a total of 140 kg ha-1 nitrogen fertilizer (N3). Rapeseed agronomic traits were
included seed yield, oil content and oil yield, stalk yield, pod residues yield and harvest
index. Spelt agronomic traits were included hulled and dehulled grain yield, content of
glumes, glumes yield, straw yield and harvest index.
In 2013/2014 and 2014/2015 year were investigated three spelt cultivars (Nirvana, Ostro
and Bc Vigor) and three variants of nitrogen topdressing: N1 - without topdressing, N2 -
25 kg ha-1 of nitrogen in one application and N3 - 50 kg ha-1 of nitrogen in two
applications, first 25 kg ha-1 N at the beginning of the growing season in spring and
second 25 kg ha-1 N at the end of tillering.
In laboratory investigation for both cultures were determined content of combustible
substances (content of carbon, hydrogen, sulfur, oxygen and volatile matter) and noncombustible
substances (content of ash, coke, fixed carbon, nitrogen and moisture). Also,
in laboratory for both cultures were determined calorific value and calculated energy
potential.
In both years were determined significant differences between studied cultivars and
hybrids of rapeseed in seed and oil yield. Significantly the highest seed yield and oil yield
achieved a conventional hybrid SY Cassidy. In 2012/2013 year the highest yield of the
stalk and empty pods achieved conventional hybrid SY Cassidy and cultivar Komado.
Increasing a rate of nitrogen, i. e., the application of 90 kg ha-1 of nitrogen in one
topdressing (N2) significantly increased seed yield, and by the application of 140 kg ha-1
of nitrogen in two topdressing (N3) increased the stalks yield and empty pods yield, but
only in extremely humid 2013/2014 year.
The investigated spelt cultivars were significantly different in dehulled grain yield and
harvest index. Significantly highest yield of hulled grains and the highest harvest index
was achieved the cultivar Nirvana. In 2014/2015 year the highest yield of straw was
achieved cultivars Bc Vigor and Ostro, and the lowest proportion of glumes achieved
cultivar Nirvana.
By increasing rate of nitrogen, i.e., the application of 25 kg ha-1 of nitrogen in the first
topdressing (N2) significantly increased straw yield only in humid 2013/2014 year and
yield of dehulled and hulled spelt grain and glumes yield in 2014/2015 year.
Results of laboratory researches have shown that spelt straw has a higher calorific value
than rapeseed stalks because it contains a higher content of carbon, coke and fixed
carbon and low content of oxygen, volatile matter and nitrogen. Spelt straw in relation to
rapeseed stalk contains less sulfur content.
The most favorable energetic traits of the rapeseed stalk had conventional hybrids SY
Cassidy and cultivar Komando.
Topdressing with larger nitrogen rate mostly had a positive effect on energetic traits of the
biomass i.e. rapeseed stalk through increasing the proportion of hydrogen and coke and
reducing content of volatile matter.
Investigated spelt cultivars were not significantly different in quality straw biomass, only in
2014/2015 year significantly lowest ash content was determined for cultivar Nirvana.
Nitrogen topdressing also had mostly positive effect on energetic traits of spelt straw
through increasing carbon content and decreasing oxygen and ash content, but also had
negatively effect due to decreasing coke content and increasing nitrogen content.
The yield of usable biomass counted 30% of the rapeseed and spelt biomass that can
pick up and drive away from the field without disturbing soil fertility and structure. In this
research, spelt straw achieved a higher yield of usable biomass (2492 kg ha-1) and the
energy yield of biomass (42455 MJ ha-1) in relation to the rapeseed stalks (2235 kg ha-1,
or 37037 MJ ha-1). With regard to the Croatian energy potential, rapeseed had higher
energy potential in relation to the spelt due to significantly larger harvested area. Thus, in
Croatia, from harvested area under rapeseed in the studied period, was possible to use
on average 764414 GJ of energy and from the area under the spelt 48529 GJ of energy.
The amount of energy from rapeseed biomass corresponds to 18258 tons of crude oil
equivalent and from spelt biomass corresponds to 1159 tons of crude oil equivalent.
Rapeseed stalks and spelt straw have high C/N ratio. Cultivar/hybrid and nitrogen
topdressing of rapeseed didn’t have significant influence on C/N ratio of rapeseed stalk.
Also, these factors didn’t have significant influence on C/N ratio of spelt straw. |
