Wheat Nutrition Bioeconomic Approach, Using Substituting Models of Synthetic with Natural Nitrogen

The paper fits in the field of bioeconomy, which aims the reconciliation between environment and economy, approaching the issue of substitution, even partially, of the synthetic nitrogen with the one biologically fixed to the wheat crop. The study began 12 years ago in a farm from Southern Romania (Burnas Plain) with a surface of 1000 ha. In order to avoid monoculture, it has been proposed a crop rotation system with five crops (200 ha for each crop), as follows: rape – wheat – corn – sunflower – peas. The effects of avoiding monoculture have immediately appeared, especially in diminishing the diseases, pests and weeds percentage with about 38.4%. An essential part of the whole algorithm is represented by the crop nutrition, mainly by the nitrogen one for wheat, since it directly affects the yields quantity and quality. Thereby, a part of the nitrogen currently applied from bag (synthesis nitrogen) has been replaced with biological nitrogen, obtained from the input provided by using peas as preceding plant (130 kg N/ha, which means an average of 26 kg N/ha/year) and by the association made by wheat with the Azospirillum brasilense bacteria (90 kg N/ha, namely an average of 18 kg N/ha/year). The total amount of substituted nitrogen is 44 kg N/ha/year. Doing a ratio between the biological and the synthesis nitrogen, it will appear that 46.4% of the nitrogen required by the plants for the whole crop rotation system can be supplied at no cost and without causing damages to the environment. The entire study wants to demonstrate that the transition to the conservation agriculture is a necessary step on our way to the bioeconomic agriculture and that, in order to achieve this objective, using natural models is crucial.