Fertilizer Fuels Rain's Infectious Cargo

A study by the University of Córdoba determines the relationship between the time from when it starts to rain until the runoff begins with the export of E. coli bacteria.

That the time that elapses between the first drops of rain begin to touch the earth and the instant in which that same earth can no longer retain more water is more or less dilated will determine the concentration of bacteria and microbes contained in that water that runs down the surface of the ground.

This conclusion is derived from the work carried out by the professor of the Department of Applied Physics of the University of Córdoba in collaboration with American researchers in which the problem of the risk of pollution of water bodies is addressed.

In places where livestock production is very high, we have opted for the reuse of the waste derived from this activity as organic fertilizer. For everything to be benefits, such as the contribution of organic matter and nitrogen that this practice implies, it is necessary to minimize risks. It is necessary to reduce to the maximum the scenarios that could be derived from the contamination of water by fecal organisms inherent in this type of fertilizer.

To evaluate the possibilities of contamination and the behavior of these organisms, Martínez and his team analyzed the behavior of E. coli bacteria (which is the reference organism for measuring faecal contamination in water) in rain events.

In a farm of 30 ha of the outskirts of Washington follows, since 2007, the procedure of application of fertilizer, sampling of the bacteria contained both in the soil and in the fertilizer, simulation of rain and sampling of bacteria in water from the runoff caused by that rain. After this starting situation, the amount of E. coli in soil and manure is analyzed again to make a balance between the quantity that has been left and that which has gone with the rain.

The great variability in the results of the project reveals the drastic changes that the same plot can suffer over the years, changing their behavior greatly. These differences are well represented by the time that elapses from when it begins to rain until that the water runs down the surface of the plot since when this time is longer, the amount of bacteria that leave the plot is lower although they have better conditions to proliferate. Under these conditions, the risk of contaminating nearby streams is lower.

The usefulness of this model lies in its value for the development of legislation by health and environmental authorities that, from it, may allocate a fee for the application of manure depending on the risk that the area has to produce this type of pollution, in order to supply healthy and safe products. With these data and the weather forecast you can also manage coastal or river beaches because, adding how much manure has been applied to that forecast, the model can predict how much pollution there will be at the beach in question and at what time the maximum peak will be given .

This tool becomes, therefore, an ally along with public health and the agricultural community.

This article has been republished from materials provided by the University of Cordoba. Note: material may have been edited for length and content. For further information, please contact the cited source.

Reference
Stocker, MD; Pachepsky, YA; Hill, RL; Martinez, G. Escherichia coli Export from Manured Fields Depends on the Time between the Start of Rainfall and Runoff Initiation. JOURNAL OF ENVIRONMENTAL QUALITY2018 Sep; 47 (5): 1293-1297. doi: 10.2134 / jeq2018.02.0081.