Inemad improved Nutrient and Energy Management through Anaerobic Digestion Project/Contract number: 289712 Call identifier: fp7-kbbe-2011-5 Funding scheme: Collaborative project Document number
Soil Nutrient Balance Inflows
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- Atmospheric deposition on agricultural land
- Use of seeds and plant material
- Processing industry, focus on biogas
Soil Nutrient Balance
Figure and Figure provide an overview of the application of mineral N and P in total tonnes per crop type in Flanders. 
Figure : Application of mineral fertilizer (nitrogen) in Flemish agriculture, 2005-2009, in tonnes (Source: Vlaamse Overheid, Departement Landbouw en Visserij) 
Figure : Application of mineral fertilizer (phosphorus) in Flemish agriculture, 2005-2009, in tonnes (Source: Vlaamse Overheid, Departement Landbouw en Visserij) The maps in Figure provide an overview of the most sensitive areas in Flanders regarding the production of nitrogen and phosphate. From these maps it is clear that these areas are located in West-Flanders, the northern area of East-Flanders and the northern part of Antwerp province. Net nitrogen production per Flemish community in kg N Net phosphate production per Flemish community in kg P2O5 Figure : Net nitrogen and phosphate production per Flemish community in 2007 (Source: Department of Agriculture and Fisheries) In Wallonia, the use of mineral fertilizers has decreased since 1995, particularly for phosphorus. The amounts applied in Wallonia remain above the European average. For its part, the production of organic nitrogen from livestock manure has been declining since 2001, mainly due to the decrease in the total number of cattles (UE-15, 2004). Figure compares the evolution of the use of fertilizers with the production of main arable crops in Walloon Region. Since 1995, there has been a decrease in fertilizer use per tonne harvested. Progress in the rational use of synthetic fertilizers reflect a greater consideration of the environment in agricultural practices, including the effect of regulations and controls implemented in the framework of the sustainable management of nitrogen in agriculture (Vandenberghe et al., 2009). Changes in the cost of fertilizers have also played a role in the trend (SPW – DGARNE, 2010). 
Figure : Production of the main arable crops and fertilizer use in Walloon Region (1995 -2006). (Source: TBE 2010- SPF Economie – DGSIE (INS); SPW - DGO3 - DEMNA). Reported in the UAA (utilised agricultural area), the amount of nitrogen (mineral and organic fertilizers) varies from 190 kg/ha to about 240 kg/ha, depending on the agricultural regions. This value is lower than the highest standards of reference (250 kg/ha for crops and 350 kg/ha for grassland) (Cellule Etat de l’environnement wallon, 2010). Figure shows the inputs and average surplus of nitrogen in agricultural soils in Wallonia. 
Figure : Inputs and average surplus of nitrogen in agricultural soils in Belgium and Wallonia (1990 - 2008). (Source: TBE 2010- SPF Economie – DGSIE (INS); SPW - DGO3 - DEMNA). In 2010, a maximum amount of 6.5 million kg N; 1.7 million kg P2O5 and 3.6 million kg K2O was allowed to be deposited in Wallonia. This maximum amount is calculated based on the amount of fertilizer really applied in Wallonia (taking into consideration crop type, location of plots in vulnerable areas, potential management agreements and derogation). For N, P, K contents of organic fertilizer applied, it was considered an average grade. The average application per ha in 2011 totalled 162.7 kg N/ha, 42.6 kg P2O5/ha and 90.10 kg K2O/ha. Table provides an overview of the types and amount of fertilizer used on Walloon soils in 2010. Table : Overview of types and amount of fertilizer used on Walloon soils in 2010 ((Source: SPW 2011, Recensements et enquêtes agricoles)
The map in Figure provides an overview of the “soil linkage rate” (TLS) in Wallonia. The soil linkage rate is the ratio between the amount of manure produced in the municipality and the amount of effluent spreadable on the municipality. 
Figure : Soil linkage rate in Wallonia (estimate for 2010) (Source: DPS, DGRNE) The distribution of farms in the Walloon Region in terms of their value of LS 3 (internal LS) shows that 80% of farms have sufficient internal application capacity (LS 3 ≤ 1). According to Gybels et al. (2009), in the Walloon Region livestock nutrient production covers about 45% of the total nitrogen input on agricultural soil. In 1990 about 95% of the total nitrogen excretion came from cattle, whereas only 3% came from pigs and not even 1% from poultry. In 2006 nitrogen excretion from cattle decreased to 90% of the total nitrogen excretion, whereas nitrogen excretion from pigs and poultry increased to respectively 4% and 3%.
In 2009, the atmospheric deposition of N in Flanders was 14,194,622 tonne N. The mean average deposition of N for Flanders in 2009 was 20.6 kg N/ha (Lenders et al., 2012). Phosphor deposition is negligible. 
Figure : N deposition (Source: Lenders et al., 2012) For 2006, atmospheric deposition of nitrogen are estimated at about 18,586 tonnes on the whole Walloon territory and make about 11.15 kg /ha. To obtain atmospheric deposition on agricultural soil, they were divided by the total surface area of the Walloon region and multiplied by the total agricultural surface: 8,175 tonnes. These depositions are relatively stable over the last fifteen years. (Gybels et al., 2009). Phosphor deposition is negligible.
Seeds and plant material contain a small quantity of N and P which ends up in the soil during sowing and planting. In 2009, the amount of N and P deposited in the Flemish soil was 703,876 and 126,319 kg respectively (Lenders et al., 2012). This is a negligible amount. In 2006, the total nitrogen input by seed use in the Walloon Region was 902.4 tons (1.19 kg/ha). (Gybels et al., 2009).
The table below provides an overview of N-fixation in crops. Table : Average N-fixation in kg per ha (Source: Vanongeval et al. (1998) and BLIVO, (*) personal announcement Alex De Vliegher, ILVO, department Plant, 2011)
For 2009, the biological N-fixation in Flanders was 5.5 million kg N (Lenders et al., 2012). For 2006, the biological N-fixation on agricultural soil of Wallonia was 4,789.5 tons of N (6.32 kg/ha). (Gybels et al., 2009).
Figure provides an overview of the energy consumption in Flemish agriculture. It can be seen that horticulture consumes the largest amount of energy, due to the need for heating the greenhouses. The livestock sector as a whole (dairy and beef cattle, and pork production) is the second largest energy consumer. Figure provides an overview of the energy use per source. The figure shows that the share and importance of petroleum products has been declining over the years (68% in 2005 as compared to 42% in 2010) in favour of natural gas (20% in 2005 as compared to 38% in 2010) due to high oil prices and Flemish government stimuli. Electricity takes up 8% of the total (in 2010), while coal is being used for additional heating (2% for the same year). Another important evolution is the increase in biomass share from 0% in 2005 to 10% in 2010. 
Figure : Energy Consumption in Flemish Agriculture per subsector, 2007-2009, in TeraJoule (Source: Vlaamse Overheid, Departement Landbouw en Visserij) 
Figure : Energy consumption in Flemish Agriculture per source, 2007-2010, in PJ (Source: MIRA on the basis of VITO energy balance Flanders)
In 2007, the livestock sector was accountable for 16% of the total energy consumption in Flemish agriculture (Platteau J. & Van Bogaert T., 2009). The pig sector (7% of the total consumption or 2,159 Tera Joule) mainly uses energy for the heating of stables, while in the dairy sector (6% of the total consumption or 1,717 Tera Joule) most energy is consumed by milking machines, milk cooling machines and tractors. The beef production sector uses 3% of the total energy consumption (equal to 792 Tera Joule). For that same year, water consumption amounted to 6,804,245 m3 (14% of total water consumption in the agricultural sector) for the pig sector, 7,339,233 m3 (15% of total) for the dairy sector and 2,180,193 m3 (5% of total) for the beef production sector.
Even though anaerobic digestion produces energy, there is a need for heat to create mesophile or thermophile conditions and electrical energy for the mixers and feed pumps. This process energy can mount up to 40% of the total biogas yield. By using combined heat and power (CHP), 12-15% of the total biogas yield can suffice as process energy (Lemmens et al., 2007). The output of digestion of vegetable, fruit and garden waste is estimated at 100-150 kWh/tonne waste and the calorific value of the gas is 18-22 MJ/Nm3. The net energy production for digestion of the different manure types (biogas production – energy need) is estimated at 1 MJ/kg DM for bovines, 4 MJ/kg DM for pigs and 9 MJ/kg DM for poultry (Lemmens et al., 2007). In regards to Wallonia, no detailed data exists for sections 2.1.5.1 to 2.1.5.3. Figure provides an overview of the energy use per sector for the year 2009. Agriculture represents less than 1% of the total energy consumption in Wallonia. For 2009, fuels used in agriculture are mainly petroleum products (1,127 GWh = 4,057,200 GJ) and electricity (69 GWh = 248,400 GJ). (SPW-DGO4, 2010). Figure : Energy consumption per sector (%) for 2009.
Figure provides an overview of the water consumption in agriculture from the water source perspective. The majority of water is pumped by the farmers themselves (superficial and deep groundwater), around one quarter is rain water, caught via greenhouses or buildings. Only around 10% is tap water, taken from the public drinking water company. The share of surface water is restricted due to the necessity of proximity of a river or stream. The greenhouse production sector uses the largest share of water (37%), followed by the dairy sector (16%) which needs a relatively large amount of water for the animals and for cleaning the milking machines. 
Figure : Water consumption in agriculture per source, 2005-2009, in m3 (Source: Vlaamse Overheid, Departement Landbouw en Visserij) No data is available in this regard for Wallonia.
For Flanders, please refer to section 2.1.6.1. In 2005, the water volumes consumed in livestock buildings in Wallonia accounted +/- 14 million m³, about 1,350 m³ per farm. They are relatively stable over the period 1997-2005, while the number of farms involved is steadily decreasing. There was a decrease in the consumption of tap water to other cheaper sources. In this regard, the total volume of water taken directly to surface water and groundwater is difficult to estimate, because we don’t have any comprehensive inventory of private wells or statistics on the practice of irrigation. Water consumption in the agricultural sector represents less than 1% of the total consumption in the Walloon Region. (Cellule Etat de l’environnement wallon, 2010).
No data is available in this regard for Flanders and Wallonia. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||