The Effect of Different Organic Fertilizers and Different Localities on Crop Yield in Conditions of Organic Farming

Nitrogen fertilization of plants during the vegetation is very problematic in terms of organic farming. The balanced crop rotation and versatile nutrition are essential for maintaining good yields and high‑quality products. The application of organic fertilizers and incorporation of green manure crops are one of the best options for achieving optimal results in organic farming. The goal of this long‑term research was to examine the effect of several different organic fertilizers and divergent experimental stations on crop yield in conditions of organic farming. a total of 6 variants of fertilization were evaluated in this experiment: 1. unfertilized, 2. green manure (GM), 3. GM + renewable external sources, 4. GM + renewable external sources + biostimulants, 5. GM + farm fertilizers, 6. GM + farm fertilizers + biostimulants. The winter wheat was sown at the start of the experiment in autumn of 2014. Therefore, green manure was not cultivated in the first experimental year. The results from the first year of this experiment showed, that the variant with renewable external resource (digestate) provided the highest yield. The average yield of wheat grain on this variant was about 7.12 t/ha, which is increased by 0.74 t/ha in comparison with unfertilized control variant. The potatoes were used as a model crop in second year of the experiment. The highest yield of potatoes coming from the second experimental year was observed on the combination of green manure + renewable external sources (compost and digestate) + biostimulants. The average yield of potatoes on this variant was about 34.08 t/ha. The yield of potatoes observed on the unfertilized variant was lower by 9.35 t/ha. The content of nitrogen in organic fertilizers (compost and digestate) was higher in comparison with other organic fertilizers used in the experiment, which probably caused these results. The winter wheat spelt was used as a model crop in the third year of the experiment. The application of organic fertilizers was completely omitted in this year. The highest average yield of spelt (5.5 t/ha) was observed on the variant called green manure + farm fertilizers. The average yield achieved on the unfertilized variant was lower by 0.7 t/ha. The result from this three experimental years point out the similarity between farming with and without animal husbandry in organic farming. The statistical differences between experimental stations were observed in experimental years