Recent research led by Tunsisa T. Hurisso from the College of Agriculture, Environmental and Human Sciences at Lincoln University of Missouri has shed light on the effects of dairy manure versus its compost on nitrogen mineralization in organic annual forage production systems. This study, published in “Agrosystems, Geosciences & Environment,” addresses a critical concern for organic farmers: how to effectively meet crop nitrogen needs while ensuring environmental sustainability.
As organic agriculture gains traction in the United States, the use of animal manure as a nitrogen source has become increasingly popular. However, the research highlights a significant challenge: the variability in nitrogen supplying potential of manure often leads to overapplication. This not only affects crop productivity but can also harm the environment.
Hurisso’s team conducted a study to compare the short-term nitrogen mineralization and microbial biomass carbon and nitrogen following the application of dairy manure (DM) and its composted form (DMC). They targeted application rates designed to provide 123 kg of potentially plant-available nitrogen per hectare in the first year and 56 kg in the second year. The findings revealed that net nitrogen mineralization varied significantly, with Year 1 showing a range of 42–277 kg N ha−1 from the different treatments. Notably, the study found that “the proportion of total N added that was mineralized in Year 1 was greater from DM than DMC,” with DM supplying up to 35% of the nitrogen compared to a mere 7% from DMC.
This research has important implications for farmers and agribusinesses. For those in the organic farming sector, understanding the differences in nitrogen availability between manure and compost can lead to more informed decisions regarding fertilization practices. The ability to optimize nitrogen supply not only enhances crop yields but also minimizes the risk of environmental degradation associated with over-fertilization.
In Year 2, the results indicated that while the nitrogen mineralization rates for DM and DMC were similar, the unamended control showed significantly lower nitrogen availability. This suggests that even in subsequent years, the choice of amendment can have lasting effects on soil health and productivity.
The study also found that microbial biomass carbon and nitrogen were more influenced by seasonal changes and soil sampling depth than by the type of organic amendment used. This insight could lead to further research opportunities in understanding soil health dynamics in organic farming systems.
As the demand for organic produce continues to rise, understanding the nuances of nutrient management through this research could open new avenues for both farmers and suppliers of organic fertilizers. The findings from Hurisso’s research underscore the importance of tailored nutrient management strategies that align with environmental sustainability goals, ultimately benefiting the agricultural sector as a whole.
