PROJECT DESCRIPTION
BACKGROUND
Pork industries are important to many local economies in Spain. However, pig farming generates slurry waste containing high levels of nutrients, such as nitrogen. Inappropriate management of this waste stream can lead to pollution of surface water, ground water and air, especially in areas of high production. This can cause significant damage to local ecosystems through processes such as eutrophication of waterways.
At the same time, there is increasing understanding of the important ecological services provided by certain forms of land use. For example, areas of forest and peatland act as important carbon sinks, removing CO2 from the atmosphere and mitigating climate change. Planting trees and other crops can also be important for extracting nutrients from the soil, preventing soil erosion and protecting and increasing biodiversity.
Reduction of greenhouse gas emissions is a key target for tackling climate change. The EU targets 20% of energy generation from renewable sources by 2020. Biogas, produced by the anaerobic digestion or fermentation of organic matter, can be an important form of renewable energy.
OBJECTIVES
The project aimed to minimise the extent of nutrient excess in soils caused by the pig farming sector by acting in three main places: in pig farms; in field application of manure; and in soils affected by agricultural nutrient excess. It aimed to show that successful solutions can improve soil quality, whilst also delivering important additional environmental benefits.
Specific sub-objectives included:
- Minimising the quantity of nutrients from manure exiting pig farms in the wastewater. It will apply techniques for optimising water use and improving waste treatment;
- Improving the efficiency of manure application in the field through the introduction of Best Available Technologies (BATs). The project will implement decision-making tools for initial fertilisation stages and advanced tele-detection techniques to determine manure application; and
- It would work to extract agricultural nutrient excess that is already present in soils, using catch crops, forest plantations and riparian buffers, which should naturally manage nutrient levels.
The project thus hoped to reduce nutrient excess in the soils and restore soil quality and functions. Plant growth should contribute to an imporved natural environment and some CO2 extraction as well as providing a source of biofuel as a renewable energy source.
The project expected to demonstrate the transferability of the proposed manure treatment and application technologies by showing that they are environmentally friendly and economically efficient. The project thus expected to contribute to the successful implementation of the EU soil strategy, which aims to protect and ensure the sustainable use of soil by preserving soil functions, preventing threats to soil, mitigating their negative effects and restoring degraded soils.
RESULTS
The LIFE+Farms for the future project, implemented across Catalonia, was structured around three pillars:
Nutrient and volume reduction, and slurry treatment:
- A large quantity of water is spilled on pig farms through drinking troughs. Deep analysis concluded that, by selecting the correct drinkers and making some adjustments in the water cycle, the volume of slurry can be reduced by up to 50%;
- A sound study of the feeding of animals concluded that. when the feed is adjusted to each growth stage, the volume of slurry generated is also reduced; and
- Solid-liquid separators were studied and tested. The solid, which is richer in organic matter and some nutrients, and contains less water, is economically more viable for transporting to locations far away from where it is produced.
Improving crop fertilisation:
- The project advised farmers on fertilisation relating to 1,200 hectares of irrigated cereal crops, with farmers becoming more aware of the environmental impact of their practices. Remote sensing techniques were tested. One of the project outputs is a free web tool available at www.ruralcat.net called Visor Agroforestal i3. It uses satellite images that provide specific data on the nutrient crop status and thus the fertiliser needed; and
- Activities aimed at fostering the use of the trailing hose system to apply manure on fields had a significant impact. The amount of new machinery steadily increased from the start of the project. The results of the application are clearly beneficial from all points of view.
Removal and valorisation of excess nutrients from the soil:
- The sowing of crops in between the main crops to remove residual nitrogen proved to be successful but, due to water scarcity in the area, the project tested using these crops as a co-substrate in an anaerobic biogas plant fed with slurry. This system proved able to extract nutrients from soil and to increase biogas production by 30-40%;
- Two riparian buffers were planted to create a biological barrier between the crop and the water course to reduce the quantity of nutrients reaching the river. The vegetation grown could be used as biomass. The quantity biomass generated was significant but, due to the biomass market in Spain, not economically viable; therefore, these measures could only be feasible with funding; and
- Lastly, the silvo-arable systems tested showed that they could be beneficial for soil and economically beneficial for farmers in the long term (50 years).
All the data obtained from these actions were analysed through a life cycle analysis and the environmental benefits were established for each measure. In particular, it was found that, when using the catch crop as a co-substrate in anaerobic digestion, CO2 emissions can be reduced by 25-35%.
In all, the project saw good acceptance by farmers in Catalonia, thanks to numerous dissemination events. The project provided knowledge for technicians, demonstrated the various measures and raised farmers’ awareness. Some of the activities initiated in this project will be further monitored by the beneficiaries and some others are expected to be applied by the farmers.
