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Nitrogen Balance, Farm classification - Coggle Diagram

- - - - Organic N fertiliser
        
        measure the %N in the Kg of fertiliser applied
      - Inorganic N fertiliser
        
        nitrogenous inorganic fertiliser has a fixed nitrogen conversion coefficient of 1000 kg/t.
        https://www.oecd.org/greengrowth/sustainable-agriculture/1916652.pdf
  - - - total numbers of live animals (cattle, pigs, sheep, goats, poultry, horses, and other livestock) in terms of different categories according to species (e.g. chickens, turkeys), sex, age and purpose (e.g. milk cow, beef cattle), multiplied by respective coefficients of the quantity of nitrogen contained in manure per animal per year
        
        HOW TO: to subtract % volatilisation of manure when applied in the field
        The loss ranges from 2 to 35% of applied amount, depending on manure and amendment type and application method
    - - Manure analyses to determine KgN/ Kg animal manure
  - - - seed N can be determined by multiplying N concentration in the seed by seeding rate.
        The uncertainty of such value is +- 10 to 20% of the applied seed N.
  - - - planted area of legume crops or pasture (e.g. field beans, soybeans, clover, alfalfa, pasture) multiplied by respective coefficients of nitrogen fixation per hectare
    - - plus the nitrogen fixation by free living soil organisms computed from the total agricultural land area multiplied by a single coefficient of nitrogen fixation per hectare
    - - determine grain and biomass yield of fresh legumes. Calculate DM yield on subsample (65 C in oven). Calculate N concentration (gN/kg) in each plant components. [BREMNER METHOD]. Multiply dry yield by N concentration.
        
        Assuming that 70% of legume N is biologically fixed, biological N fixation, (kgN/ha when only grain N is removed from the soil, is calculated as:
        Biological N fixation = 0.7 (Biomass N + 0.33 total aboveground biomass N)
        Where total aboveground biomass N refers to the sum of N contents in grain and biomass. 0.33 is assumed to be the % of belowground plant parts. The value 0.33 * total aboveground biomass N refers to belowground biomass N.
        
        When total aboveground biomass N is removed that also includes forage legume, biological N fixation is calculated as:
        Biological N fixation = 0.7 0.33 total aboveground biomass N
        
        For legume cover crops and green manure crops where total aboveground biomass N is returned to the soil, biological N fixation is calculated as:
        Biological N fixation = 0.7 1.33 total aboveground biomass N
  - - - The amount of N fixation depends on soil organic matter, water, and inorganic N contents, pH, and P and Mo level.
        
        In agroecosystems, nonsymbiotic N fixation is small and ranges from 3 to 7 KgN/ha/yr
    - - calculation of soil bateria and fungi activity and link with possible assumed N fixation
- - - - Denitrification in peat soils is high due to the high organic
        matter content and high groundwater levels (Van Beek et al., 2004).
        
        In soil with many fine soil particles, such as clay soils, the risk of
        denitrification is higher than in soils with coarser particles, such as sandy soils (Granli and Bøckman,
        1994).
        
        As the groundwater level comes into contact with the root zone, less oxygen and more nitrate are available for
        denitrification. The denitrification is therefore greater wet sandy soils (shallow groundwater stage) than in dry sandy soils (deep groundwater stage).
        
        No distinction is made between clay and peat soils on the basis of the groundwater level.
        
        The leaching sensitive sandy soils include the soils with an average highest groundwater level (GHG) of 0.70 m below
        ground level. These are the soils with Gt VII and Gt VIII and some of the soils with Gt VI (Van Kekem et al.,
        2005).
    - - The content of degradable organic matter is higher in grassland than in arable land (Velthof, 2003), which means that there is more denitrification in grassland than in arable land.
    - - lab measurements use 15N isotope method
  - - - fU[g,b,gt,j] is the leaching faction for crop g on soil type b with groundwater stage gt and in agricultural
        practice year j;
        U[g,b,gt,j] the nitrogen leaching in kg/ha/year for crop g on soil type b with groundwater stage gt and belonging to the agricultural practice year j;
        O[g,b,gt,j] nitrogen surplus in kg/ha/year for crop g on soil type b with groundwater stage gt and belonging to the agricultural practice year j.
  - - - depends on the extent of soil cover by plants, source of N applied precipitation intensity, and soil crusting. Such loss usually amounts to <3 kg N/ ha/ yr
  - - - Nitrogen loss ranges from 10 to 20% of applied N for inorganic N fertilizers and 15 to 30% for manures.
        Nitrogen loss through ammonia volatilization can be measured in the field using complex experiments. Because of the complexity and difficulty in measuring ammonia volatilization, the values can also be estimated for various N sources, soil conditions, and management practices.
        
        The accuracy of such measurements and estimates ranges from 20 to 50% of applied N
  - - - estimated by multiplying the amount of annual soil loss by soil organic matter content and 2 (conversion factor)
  - - - static and dynamic chambers and micro meterological methods
    - - If measurements cannot made, NOx emissions can be estimated as 1–2% of applied N input
- - - - quantity of harvested forage crop production (e.g. fodder beets, hay, silage) and grass consumption from temporary and permanent pasture multiplied by respective coefficients of nitrogen uptake to produce a tonne of forage.
    - - quantity of harvested crop production (e.g. cereals, root crops, pulses, fruit crops, vegetables and industrial crops) multiplied by respective coefficients of nitrogen uptake to produce a tonne of harvested crop;
        
        Determine dry matter yield by drying a sample at 65 C for 3–7 d and convert yield to dry matter basis.
        Grind a subsample of grain and/or biomass to <1 mm and determine N concentration by using methods similar to soil samples as described by Bremner.
        Determine crop N removal (kg N/ ha) by multiplying crop yield by N concentration.