The potential bio-availability of minerals from food, i.e. agricultural products, is mainly subjected to the concentration of
anti-nutrients, due to its high affinity to bind elements and make them unavailable for humans from digestive tract. Thus,
increasing the mineral concentration in grain is just one point in the string that can improve food quality, but reduction in
concentration of anti-nutrients, such as phytates, is of great importance, too. [1,2] As intercropping and use of bio-fertilizer
represent integrative part of sustainable agriculture which influence nutrient use efficiency [3,4], their combination seems
to be a good way to manage nutrients uptake and accumulation, and anti-nutrients concentration in grain. Therefore, this
research aimed to examine the impact of soybean - common millet arrangement in intercropping, together with bio-fertilizer,
on potential bioavailability of essential elements in grain. A two-year field experiment was conducted with soybean and
common millet. Mono-crops (T1 - soybean, T2 - millet), as well as three planting patterns of intercrop (T3 - alternating rows
of soybean and common millet; T4 - alternating strips of two rows of soybean and two rows of millet and T5 - alternating
strips of two rows of soybean and four rows of millet) were set up in 2018 and 2020. The bio-fertilizer Coveron (BF) (containing
mycorrhizal fungi, Trichoderma and plant growth-promoting rhizobacteria) was also included in same combinations,
as a subplots, as well as variant without BF (BFƟ). After determination of concentrations in grains, the molar ratios between
phytic acid (Phy) and magnesium (Mg), calcium (Ca), iron (Fe) and zinc (Zn) were evaluated. Results showed that intercropping
and bio-fertilizer significantly affected molar ratios between phytic acid and essential elements. Regarding to the
soybean, all 4 ratios showed smaller values in intercropping comparing with mono-crops (both in plots with and without
fertilizer). Intercrops + BFƟ decreased Phy/Ca, Phy/Mg and Phy/Fe ratios down to the 0.31 (T4 and T5), 0.16 (T4) and
14.03 (T4), respectively, while intercrops + BF decreased Phy/Zn ratio down to the 25.25 in T3 + BF. These lowest values
could be related to lower accumulation of Phy and greater accumulation of minerals in intercropped soybean, due to the
presence of cereal (millet) and its ability to excrete phytosiderophores, which promotes mineral uptake [5]. Nevertheless,
situation for common millet was different. Ratios of Phy/Ca, Phy/Mg and Phy/Zn had the lowest values in mono-crops (both
in BF and BFƟ variants), while the value of Phy/Fe was the lowest in T3 + BF (23.88). Such results suggest soybean -
common millet intercropping as a good sustainable agricultural practice to enhance bio-availability of essential elements
in grain of soybean. On the other side, positive impact of BF was pronounced in millet, enhancing potential bio-availability
of examined minerals in grain by lowering values of all 4 ratios. These findings can be connected to beneficial effect of
microbes on nutrients uptake by cereals [6], highlighting the tested combination of fungi and plant growth-promoting rhizobacteria
as a sustainable strategy to increase grain quality. However, although this research proved positive effects of
soybean - common millet intercropping and bio-fertilizer on potential bio-availability of essential elements, further research
is needed to determine the most suitable combination for increased quality of both crops
