Boron in irrigation water and its interactions with soil and plants: an example of municpal landfill leachate reuse

English. In several countries, leachate is successfully treated by recirculation to the vegetated landfill cover, as it contains several micro and macronutrients for plant growth. However, the proportion and concentration of some parameters can negatively affect the plant growth and soil quality in the case of high leachate input. The presented research discusses B in leachate and its interactions with soil and plants. A ten-month field research was performed on 1.1 ha of the closed and covered municipal solid waste landfill site irrigated with landfill leachate. B concentration was analysed in leachate, landfill soil cover and in plant leaves. Total B concentration in leachate ranged from 0.8 to 3.83 mg/L. Monthly B mass load on the covered landfill site ranged between 0.2 _ 1.5 kg/ha. The concentration of bioavailable B in soil cover gradually increased and ranged between 0.5 _ 2.75 mg/kg dry weight soil. The average total B concentration in clover leaves was 23.9 mg/kg, in grass leaves 4.5 mg/kg, in the leaves of younger willows in the new part of the landfill cover 41.3 mg/kg and in the leaves of the older willows in the old part of the landfill cover 81.8 mg/kg. Leachate application increased plant growth during the observation period and there were no toxic effects on plant leaves, although B concentrations were higher compared to usual concentrations found in natural environment.

Slovenian. V različnih dr_avah izcedno vodo uspe_no čistijo s pomočjo vračanja na vegetativno prekritje odlagali_ča, saj vsebuje več mikro in makrohranil za rast rastlin. Pri tem lahko razmerje in koncentracija nekaterih parametrov v izcedni vodi ob velikem vnosu v tla negativno vpliva na rast rastlin in kvaliteto tal. Predstavljena raziskava obravnava B v izcedni vodi ter njegove interakcije s tlemi in rastlinami. Deset mesečna erenska raziskava je bila opravljena na 1,1 ha zaprtega in prekritega odlagali_ča komunalnih odpadkov, ki je bilo namakano z izcedno vodo. Koncentracijo B smo analizirali v izcedni vodi, talnem prekritju odlagali_ča ter v listih rastlin. Celokupna koncentracija B se je v izcedni vodi gibala med 0,8 in 3,83 mg/L. Masni vnos B na prekritje odlagali_ča se je gibal med 0,2 in 1,5 kg/ha. Koncentracija biolo_ko razpolo_ljivega B v tleh je zaradi vnosa izcedne vode postopoma nara_čala in se gibala med 0,5 in 2,75 mg/kg suhih tal. Povprečna celokupna koncentracija B v listih detelje je zna_ala 23,9 mg/kg, v listih trave 4,5 mg/kg, v listih mladih vrb novega dela prekritja 41,3 mg/kg in v listih starej_ih vrb starega dela prekritja 81,8 mg/kg. Vnos izcedne vode je pospe_il rast rastlin v času obdobja opazovanj. Na listih rastlin ni bilo opaziti strupenih učinkov kljub temu, da so bile koncentracije B vi_je v primerjavi z koncentracijami, ki jih običajno najdemo v naravnem okolju.