The biological nitrogen fixation as an imperative in the tenability system

Abstract

The information on the biological nitrogen fixation has been having an increasing application within the system of organic food production. The application of inoculates with certain groups of diazotrophs results in saving expensive mineral fertilizers, preserving soil biogeny, reducing financial inputs, which represents one of the major principles of sustainable agriculture. Bacterisation was performed with the liquid seed inoculum of the maize hybrid ZP SC 704 and the wheat variety Leda. The inoculum consisted of a mixture of selected diazotrophos and their highly effective strains. The following variants of mineral N fertilizers were used in the trial: control K, N1 - 80 kg ha-1, N2 - 120 kg ha-1. Values of parameters of soil biogeny (total number, abundance of diazotrophs, ammonifier, enzymic activities), were higher under bacterisation conditions in both plant species, and were accompanied with higher grain yields. There were no significant differences in value increases of investigated parameters between fertilizing variants N1 and N2 hence it can be concluded that the application of bacterisation can rationalize the utilization of mineral fertilizers, what is of a significance for sustainable agriculture.

Koncept održive poljoprivrede podrazumeva proizvodnju biološki ispravne hrane uz očuvanje agroekološke ravnoteže, gde pored uloge i značaja agrotehničkih mera, sve veći značaj imaju i mikroorganizmi. U proizvodnji zdravstevno bezbedne hrane sve se više primenjuju i saznanja o biološkoj fiksaciji azota. U istraživanjima je obavljena bakterizacija tečnim inokulumom semena kukuruza ZP SC 677. U inokulumu se nalazila smeša odabranih vrsta diazotrofa i njihovih visikoefektivnih sojeva: -Azotobacter chroococcum soj 84; 2-Azospirillum lipoferum soj 2; 3-Klebsiella planticola soj 4; 4 -1 + 2 + 3 + Bacillus megaterium + Azotobacter vinelandi + Bacillus subtilis; 5 - 1 + 3 + Bacillus megaterium + Azotobacter vineland i+ Bacillus subtilis. U ogledu je obavljeno đubrenje mineralnim azotnim đubrivima: bez đubrenja - kontrola K, N1-30, N2-60, N3-80 i N4-80 kg N.ha-1. Vrednosti pokazatelja biogenosti zemljišta (ukupan broj, brojnost Azotobactera, bakterija iz ciklusa kruženja fosfora), u uslovima bakterizacije zavisile su od doza primenjenog mineralnog azota, kao što je zavisila i visina prinosa zrna. Najveće vrednosti ispitivanih parametara utvrđene su pri đubrenju sa 60 i 90 kg N.ha-1,te se može zaključiti da bi se primenom bakterizacije mogla racionisati upotreba azotnih mineralnih đubriva, što je svakako značajno s gledišta održive poljoprivrede.