On this page you will find our Annual Narratives about Øgro. In the Annual Narratives you will find the results from experiments with Øgro fertlizers on different crops around Denmark.
The most important experiences
Read more about the experiences and the different experiments in the Annual Narratives below.
Study results with breakdown of bone meal
Organic fertilizers contain nitrogen in organic form, more or less degraded, and some completely converted to inorganic nitrogen. Inorganic nitrogen is available in the soil as nitrate or lightly-bound as ammonium to the earth’s colloids. When the soil is fed fertilizers, it will be included in the soils total pool of nutrients in a dynamic interaction with the plants and microorganisms in the construction and degradation of organic matter. These conditions naturally affect the nutritional supply of the crop through the growing season. Other factors also influence the nitrogen pool’s release of nitrogen, including the carbon-nitrogen ratio of the fertilizer, the time of application, application method, the quality of the precipitation, the soil moisture and the temperature.
The utilization of the nitrogen, or the utilization rate, is called the value number and indicates a percentage of the first year efficiency of 100kg total nitrogen in organic fertilizer in relation to 100kg nitrogen in the reference fertilizer. In the same way as mineral fertilizers are not necessarily available to the plants immediately after application, the organic fertilizer for the above-mentioned reasons is not either. It is of great important in the cultivation of plants to know exactly how fast the nitrogen is converted and becomes available to the plant, and therefore experiments have been developed for that purpose. Øgro is estimated to ave a utilization rate of 70%, according to the note on the determination of field power prepared by SEGES.
Read the SEGES memorandum about the determination of field effect here.
Fiels experiments in Sweden
In several Swedish field experiments on grains with meat and bone meal (Biofer and Ekoväx) 50-90% of the total nitrogen was available to the crop in the year of application. (Delin & Engstrøm, 2014). The nitrogen in meat and bone meal, is commonly made available to the plants within 1-2 months after application (Delin et al, 2010). In a 2012 field experiment, Øgro shows significant yields for barley and oats with a utilization rate of 89 compared to pig manure.
Conclusion and evaluation
High nitrogen effects in bone meal has been determined in many Danish and Swedish studies. Precipitation as well as location gives the greatest ensuring of positive effects. New experiments may enlighten variations in nitrogen-effect. Climate conditions and timing of use explain a substantial part of the variation in utilization. The nitrogen effect will subside after 1-2 years, while the effects on the soils fertility persists. Part of the phosphorus contribution is seemingly available during the application year and it is expected that the utilization of phosphorus is 100% over time.