The CT BETA presents the results of 18 years of monitoring a slurry fertilisation trial in Osona

As part of an Annual Technology Transfer Plan Seminar in Torelló, the BETA Technology Center at UVic-UCC presented the results of a trial it began in 2006, which examines the effects of fertilisation with pig slurry on double-annual cropping systems in dry farming conditions in the Osona region.  

The study focuses on evaluating the effects of nitrogen fertilisation with pig slurry on crop production and fodder quality, on the dynamics of nitrates in the soil and on the quality of the soil (physical, chemical and biological). This project seeks to leverage the data collected over 18 years to study the evolution of various edaphic parameters, and to demonstrate the impact of fertilising with pig manure on soil quality. 

Some significant observations 

The trial, coordinated by Carme Casas, a researcher at the CT BETA, shows that in the double-annual cropping systems on the Vic Plain, the performance of the summer crop depends entirely on rainfall levels between June and September. In the current context of climate change, with longer periods of drought in summer, summer crops would obviously not be viable if current trends persist. 

The results show that for winter crops, increasing the use of fertilizers with pig slurry significantly increases production levels. Meanwhile, no significant changes were observed in the production levels of summer crops in these double-annual cropping systems. In conditions of low levels of rainfall, rainfed crops use the nitrogen in the soil less efficiently, and this means that the nitrate content may increase significantly if the levels of fertilisation are too high. As a result, exceeding the fertilisation limit of 170 kg N/ha in double-cropping systems like the one studied, which by law is the current application limit, is not recommended. 

Major changes were also observed in the soil's stable organic matter, with a significant decline in humic and fulvic acids, proportional to the dose of nitrogen applied, and these factors have a direct impact on its fertility. 

Osona, a region known for its high levels of livestock farming, has found application in agriculture uses to be the most economical and natural use for the waste animals produce. This practice is crucial for maintaining agricultural production levels, as it means that the use of organic fertilisers can be optimised as fertiliser for crops. The practice of double-annual cropping is common in various farms in Osona, and involves a combination of a winter cereal and a summer cereal for use as fodder. The fertilisation must be performed properly, especially with regard to nitrogen, due to the unique characteristics of these farms. 

This research project has been funded in recent years by Operation 01.02.01 for Technological Transfer of the 2014-2020 Catalonia Rural Development Programme. A document will be drawn up on the fertilisation strategy in double-annual systems under dry farming conditions in a sub-Mediterranean climate based on the results obtained in the trial.