Influence of soil amended with zeolite and/or mineral N on agronomic performance and soil mineral N dynamics in a soybean–winter triticale crop rotation field experiment

Although there are numerous studies describing the positive influence of legumes as cereal pre-crops, little information exists on the specific crop rotation soybean–triticale. Besides that, fertilization of soybean is very complex due to its symbiosis with rhizobia where mineral nitrogen could have negative effect, therefore new soil conditioners, e.g. zeolite, need to be examined. An investigation in growing seasons 2017 and 2017/2018 was established to study these knowledge gaps in a combined field experiment, where soil mineral nitrogen (SMN) was also monitored. Firstly, the influence of soybean seed bacterial inoculation (inoculated and non-inoculated seeds) as factor 1, and four fertilization treatments (1—no fertilizer, 2—600 kg zeolite/ha, 3—30 kg mineral N/ha (at sowing) + additional 70–90 kg/ha of mineral N, and 4—combination of treatments 2 and 3) as factor 2 on soybean yield performance and nutritional composition was evaluated. Neither factor influenced soybean seed yield (average 3128 kg/ha). However, zeolite had favourable effect on root nodulation where the number of nodules and nodule dry mass per plant were significantly increased. Secondly, winter triticale was sown after soybean harvest on the same plots. Only 40 kg N was applied at BBCH 30 (beginning of stem elongation) to the whole experiment. Interaction of soybean experimental factors significantly influenced the triticale grain yield. Finally, regression analysis revealed that triticale grain yield (average 5537 kg/ha) was highly dependent (R2 = 0.927) on initial SMN content, left after soybean harvest.