| Abstract | Baš poput ostalih mahunarki, i grašak (Pisum sativum L.) je vrlo vrijedna proteinska kultura pogodna i za ljudsku ishranu i ishranu domaćih životinja. Zrno graška u prosjeku sadrži 23% proteina, stoga se može koristiti kao koncentrirano krmivo u ishrani domaćih životinja (Uher, 2014). Prinosi zelene mase u čistoj sjetvi mogu iznositi 25 - 35 t/ha, dok u kombinaciji s žitaricama, prinosi graška dosežu i do 50 t/ha. Sjetva jarog graška na međuredni razmak od 20 cm kao i njegov brzi početni porast, ponekad nisu dovoljni za obranu usjeva jarog graška od korova (Anonymus, 2016a). Navedena činjenica osobito može doći do izražaja ako početni rast jarog graška koče rezidui herbicida u tlu. Mnogi herbicidi imaju naglašeno perzistentno djelovanje te ostavljaju aktivne rezidue u tlu sve do žetve, ili čak i nakon žetve. Perzistentnosti herbicida u praksi često se ne pridaje dovoljno pažnje, pa se siju kulture osjetljive na rezidue prethodno primijenjenog herbicida. Navedeno u određenim slučajevima može ograničiti izbor kultura u plodoredu. Herbicid nakon primjene i distribucije po fazama tla podliježe kompleksnim i vrlo dinamičnim skupinama procesa koje razvrstavamo u procese gubitaka i procese razgradnje.Gubici herbicida obuhvaćaju četiri skupine procesa: adsorpciju (vezanje herbicida na koloidetla), apsorpciju (usvajanje herbicida od strane biljke), ispiranje (gubitak herbicida premještanjem u dublje slojeve tla), isparavanje (gubitak hlapljivih herbicida isparavanjem u atmosferu) te spiranje (osobito na nagnutim terenima). Procesi razgradnje podrazumijevaju mikrobiološku, fotokemijsku i kemijsku razgradnju molekule herbicida. Vrlo su važni jer se razgradnjom smanjuje aktivna količina herbicida u tlu. Svi ovi procesi ovisni su o vrlo kompleksnoj interakciji karakteristika herbicida, značajki tla i klimatskih prilika te određuju dužinu perzistentnosti herbicida (Ostojić, 1989).
Mezotrion ne perzistira značajno u tlu, pa se pretpostavlja da neće ograničavati sjetvu kultura u plodoredu, odnosno djelovati fitotoksično na kulture koje slijede kukuruz u plodoredu. No, kako je perzistentnost rezultat interakcije herbicida, tla i klime, može se očekivati da će i njegova perzistentnost varirati ovisno o različitim pedoklimatskim uvjetima i primijenjenim dozama (Ostojić, 2004). Ograničenje primjene navedenog herbicida odnosi sena: šećernu i stočnu repu, ciklu, salatu, špinat, grašak, grah, te ostale Phaseolus i Vicia vrste,koje se 24 mjeseca nakon primjene mezotriona ne smiju sijati na istoj površini (Syngenta,2016). |
| Abstract (english) | Spring pea (Pisum sativum L.) is a very valuable protein crops, suitable for human consumption and animal nutrition. It is grown in rotation, and growing is recommended in same area every four years. Before sowing of spring peas, it is important to take care of the pre-culture and the history of the use of herbicides in the previous crop. In fact, some herbicides used in previous crop (residues), can lead to a variety of adverse consequences. The time during which an herbicide remains in an active form in the soil depends on the characteristics of the molecule (degradation method, the water solubility, the rate of application, etc.) and environmental factors (soil type, temperature, precipitation, etc.). The purpose of this diploma thesis was to investigate the sensitivity of spring peas on the application of reduced (1/8, 1/4, 1/2), recommended, twice and four times higher doses of herbicide mesotrione. Assessment of the effect of treatment was determined by visual evaluation of damage (0 - 100%) and by weighing the fresh and dry weight of above ground of spring peas. The survey results indicate an increase in damage, which depends on increasing doses of mesotrione. The lowest percentage damage (43%) was observed 14 days after application of herbicide treatment which is applied the lowest dose (1/8 recommended dose) and the highest (88% damage aboveground mass), where the treatment is applied four times higher than the recommended dose. During the second evaluation (21 days after herbicide application), in all treatments, showed an increase of progression initial damage from 60% 1/8 dose of mesotrione to 98% with four times higher than the recommended dose. In the last evaluation (28 days after herbicide application) in all treatments, except where applied four times higher dose of mesotrione, recorded goods plant regeneration. Dry mass (dry weight) spring pea plants to herbicidal treatments were all significantly lower than the control. The minimum (20,31%) reduction of dry weight was observed on treatment is applied wherein the lowest (1/8) the dose, while it is almost completely (91%) and completely destruction (100%) of spring pea plants found in the treatments with the double and quadruple higher dose than recommended mesotrione. |
