Influence of application of ash and mowing time on economic and morphological properties of switchgrass (Panicum virgatum L.)

Sve veća potrošnja fosilnih goriva dovodi do iskorištenja njihovih rezervi, porasta cijene i zagađenja okoliša. Iz tih razloga, obnovljivi izvori energije postaju sve važniji. Takvi izvori uključuju i biomasu energetskih kultura iz koje je moguće proizvesti tekuća biogoriva, bioplin, električnu ili toplinsku energiju. Raspodjela površina za uzgoj kultura za hranu i energetskih kultura može biti problem. Jedno od rješenja je uzgoj energetskih kultura na manje plodnim, marginalnim tlima. Divlje proso je višegodišnja vrsta prilagodljiva različitim klimatskim uvjetima i tipovima tala i zato se može uzgajati na širokom rasponu staništa. Zbog dobro razvijenog korijenovog sustava dobro podnosi suha tla, ali i vlažna, skeletna, siromašna ili kisela. Ipak najbolje rezultate daje na tlima neutralne reakcije. Prilikom uzgoja nema prevelikih zahtjeva, a na istoj površini može rasti 10 i više godina. Kako su marginalna tla često siromašna i kisela, pepeo izgorene biomase može podići pH vrijednost tla jer je alkalne reakcije. Osim kao kalcifikator, može imati ulogu i gnojiva. Bitno je da pepeo koji se koristi u te svrhe ne bude kontaminiran štetnim tvarima. Cilj rada je utvrditi utjecaj primjene različitih doza pepela drvene biomase i roka košnje na gospodarska i morfološka svojstva divljeg prosa. Gnojidbeni tretmani pepelom nisu značajno utjecali na prinose suhe tvari, visinu biljke i sadržaj suhe tvari u jesenskom i proljetnom roku žetve. Zabilježen je prosječni prinos suhe tvari 28.81 t/ha, prosječna visina biljke 2.35 m, prosječni sadržaj suhe tvari 39.47 % u jesenskom i prosječni prinos suhe tvari 23.35 t/ha, te prosječni sadržaj suhe tvari 86.52 % u proljetnom roku žetve. Značajan pad prinosa suhe tvari i rast postotka suhe tvari zabilježen je u proljetnom roku.The occurrence of increased consumption of fossil fuels is leading to usage of reserves, rising prices and environmental pollution. For those reasons the renewable energy sources are becoming increasingly more important. These sources also include biomass energy crops from which it is possible to produce liquid biofuels, biogas, electrical or thermal energy. There can be a problem with the distribution of areas for cultivation of crops for food and energy sources. One of the solutions for cultivation of energy crops is to grow them on less fertile, marginal soils. Switchrass is a perennial species that is capable of adapting on different climatic conditions and soil types so it can be grown on vide wide range of environments. Because of its well-developed root system, it tolerates dry soils well, as well as wet, skeletal, poor or sour. Though it achieves the best results on soils of neutral reaction. It's not too demanding during breeding and it can grow on the same area for 10 or more years. Because marginal soils are very often poor and sour, the ash of burned biomass can rise the pH value of the soil because of its alkaline reaction. Except as calcificator, it can also have a role as compost. It is important the ash which is being used in those purposes does not get contaminated with harmful substances. The goal of this work is to confirm the influence of different doses of ash of wooden biomass and mowing period on economical and morphological performances of switchgrass. Fertilization treatments of ash did not significantly affect the yields of dry matter, height of the plant or the content of dry matter in autumn and spring harvest season. It is recorded that the average yield of dry matter is 28.81 t/ha, average height of the plant 2.35 m, average content of dry matter 39.47 % in autumn and average yield of dry matter 23.35 t/ha, and average content of dry matter 86.52 % in spring harvesting season. Significant drop of yield of dry matter and growth percentage is noted in spring season