Prinos i kvaliteta sjemena šećerne repe u ovisnosti o sklopu i gnojidbi dušikom : doktorska disertacija - Pospišil, Milan, agronom; Mustapić, Zvonko (Zagreb : M. Pospišil, 1996)
Sažetak: Ova istraživanja provedena su s ciljem da se utvrde i kvantificiraju razlike u prinosu i kvaliteti sjemena šećerne repe koje nastaju u jednakim uvjetima proizvodnje interakcijom gustoće sklopa i gnojidbe dušikom. Istraživanja su provedena kroz poljske pokuse postavljene na lokaciji Zagreb-Maksimir u 1991/92., 1993/94. i 1994/95. godini na pokušalištu Agronomskog fakulteta, na eutrično smeđem, antropogeniziranom tlu. U pokusu su istraživana 4 različita sklopa biljaka sjemenske šećerne repe (majčinske i očinske komponente) nakon prezimljenja usjeva (40000, 80000, 120000 i 160000 biljaka po ha) i 3 razine gnojidbe dušikom (60, 120 i 180 kg N/ha) primijenjenim u dvije prihrane početkom proljetne vegetacije i neposredno prije izbijanja cvatne stabljike. Pokusi su bili dvofaktorijelni, postavljeni prema split-blok metodi u pet ponavljanja.
U pokusu je korištena sorta OS-Nada, odnosno njena majčinska i očinska linija. Na osnovi trogodišnjih istraživanja i postignutih rezultata moglo bi se zaključiti da su na rast i razvoj sjemenke šećerne repe dominantan utjecaj imale hidrotermičke značajke klime. I pored određenih pravilnosti, visina prinosa i kvaliteta sjemena ovisili su i o vremenskim prilikama osobito u vrijeme dozrijevanja. Kao posljedica razlika u akumulaciji suhe tvari, produktivnosti fotosinteze i apsopciji dušika utvrđene su i razlike u prinosu sjemena ovisno o broju biljaka i gnojidbi dušikom. Prinos primarno dorađenog sjemena signifikantno je rastao do 80000 biljaka/ha u 1991/92. i 1993/94. godini, odnosno do 120000 biljaka/ha u 1994/95. godini. Količina dušika u prihrani od 120 kg/ha značajno je povećala prinos primarno dorađenog sjemena u odnosu na 60 kg/ha.
Daljnjim povećanjem količine dušika na 180 kg/ha prinos sjemena je i dalje rastao, ali ne i statistički opravdano. Interakcijsko djelovanje sklopa i gnojidbe dušikom na prinos sjemena šećerne repe nije bilo statistički opravdano ni u jednoj godini istraživanja. Produkcija sjemena po biljci značajno opada povećanjem sklopa od 120000 biljaka/ha, a daljnjim povećanjem gustoće pad je znatno manji. Povećanjem količine dušika u prihrani, rasla je i produkcija sjemena po biljci. Prinos sjemena u sjetvenim jedinicama najviše je ovisio o prinosu primarno dorađenog sjemena (r=0,80**), prinosu sjemena po hektaru (r=0,80**), iskorištenju sjemena (r=0,74**) i klijavosti (r=0,54**). Utvrđena je ipozitivna korelacija između veličine indeksa lisne površine i prinosa sjemena u sjetvenim jedinicama (r=0,43**).
Najveći udio u prinosu sjemena imala je frakcija 4,5-5,5 mm (34%), a iza nje slijedi frakcija 3,5-4,5 mm (32,3%). Povećanjem populacije biljaka povećalo se učešće frakcije3,5-4,5 mm, a smanjivalo učešće frakcije 4,5-5,5 mm u prinosu sjemena. Povećanje količine dušika u prihrani smanjilo je učešće frakcije 3,5-4,5 mm te pokazalo tendenciju porasta učešća frakcije4,5-5,5 mm u prinosu sjemena. Na klijavost sjemena utjecaj istraživanih čimbenika bio je slabije izražen. U klimatski, za kvalitetu sjemena povoljnijoj 1993/94. godini najveća klijavost ostvarena je kod sklopa od 120000 i 160000 biljaka po hektaru. U sušnoj 1991/92. godini povećanje količine dušika sa 60 na 180 kg/ha pokazalo je tendenciju smanjenja klijavosti. Broj biljaka po jedinici površine i količina dušika u prihrani nisu utjecali na masu 1000 sjemenki i jednokličnost.
Dakle, za visok prinos i dobra kvalitativna svojstva sjemena šećerne repe neophodno je postići sklop od 120000 do 150000 biljaka/ha u žetvi, uz dvije prihrane s ukupno 120 kg N/ha.
Summary: These investigation were carried out with the aim to determine and to quantify the differences in the yield and quality of the sugarbeet seed which are archived under the same porduction conditions by the interaction of the plant density and nitrogen fertilization. The investigations were carried out by means of field experiments of field experiments on the location Zagreb - Maksimir in 1991/92, 1993/94 and 1994/95 on the experimental area of the Faculty of Agriculture, on eutrically brown, antropogenized soil. Four different seed sugarbeet plant densities ( female and male components) were being investigated in the experiment after the overwitering of (40000, 80000, 120000 and 160000 plants per hectare) and 3 nitrogen rates (60, 120 and 180 kg N/hectare) applied in two top dressings
at the beginning of spring vegetation and immediately prior to flower stem springing. The experiments were two - factorial, set according to the split-bloc method in five replications. The cultivar OS-Nada was used in the experiment, that is to say the maternal and paternal lines of this cultivar. On the basis of three year long investigation and the results achieved we could conclude that the dominant influence on the growth and development of the seed sugarbeet was exerted by the hydro - thermic climate features. And beside certain regularities, the level of seed yield and seed quality also depended on the weather conditions, expencially at the time of ripeining process.
As a consequence of diferences in the accumulation of dry matter, in the productivity of photosynthesis and in the nitrogen absorption, the differences in the seed yield were established as well, according to the plant density and nitrogen fertilization. The yield of primary processed seed (processed for components of final product) rose significantly up to 80000 plant/hectare in 1991/92 and 1993/94, and up to 120000 plants/hectare in 1994/95. The nitrogen rate un the nutritional process of 120 kg/hectare significantly raised the yield of primary processedseed in relation to the 60 kg/hectare. With the further increase of the nitrogen rate to 180 kg/hectare, the seed yield rose, but not statistically justified.
The interactional influence of the plant density and nitrogen fertilization on the sugarbeet seed yield was statistically justified in none of the investigation years. The production of seed per plant is falling down significantly by the plant population increase to 120000 plants/hectare, whereas with further plant density increase this fall is much lower. Whit the increase of the nitrogen rate in the nutritional processes, the seed production per plant rose. The seed yield in the units of seed depended mostly on the primary procesed seed yied (r=0,80**), on the raw seed yield per hectare (r=0,80**), on the seed utilization (r=0,74**) and on the germination (r=0,54**). A positive correlation between the leaf area index and the seed yield in the units of seed has been established as well (r=0,43**).
The fraction 4,5-5,5 mm had the greatest share in the seed yield (34,6%), followed by the fraction 3,5-4,5 mm (32,3%). With the increase of plant population, the share of the fraction 3,5-4,5 mm in the seed yield increased, whereas the share of the fraction 4,5-5,5 mm in the seed yield decreased. The increase of the nitrogen rate in the nutritional processes drcreased the share of the fraction 3,5-4,5 mm and exhibited the tendecy of the increase of the share of the fraction 4,5-5,5 mm in the seed yield. The influence of the ivestigated factors on the seed germination was less presented. In the climatic, more favorable year for quality of seed 1993/94, the higest level of germination was achived by the plant density of 120000 and 160000 plants per hectare.
In the dry 1991/92 year the increase of the nitrogen rate from 60 to180 kg/hectare showed tendency of the germination decrease. The number of plants per surface unit and the nitrogen rate in the nutritional processes did not affect the 1000 seed weight not the single-germination. That is to say, for the tihgh level of seed yield and good qualitative properties of sugarbeet seed it is necessery to archive the plant population of 120000 to 150000 plants per hectare in the harvest, with two top dressings with altogether 120 kg N/hectare.
Doktor biotehničkih znanosti - agronomija
Mentor: Zvonko Mustapić
Bibliografija: str. 139-146
Summary
Keywords: Šećerna repa -- Gnojidba