Skip to main content

Table 2 Inputs and yields for system components according to the present farming household system (in a year)

From: Energy efficiency in an integrated agro-ecosystem within an acidic soil area of the Mekong Delta, Vietnam

Item Unit Equivalent factor (Jex/Unit) Reference Pig production Fish production Orchard
Renewable resource (RR)
 Sunlighta J 1.02E− 05 [11, 18, 21] 1.17E+ 08 3.26E+ 09 1.63E+ 09
 Windb J 3.12E− 02 [18, 21] 7.08E+ 08 1.97E+ 10 9.83E+ 09
 Evapotranspirationc J 6.26E− 01 [11, 18] 1.11E+ 12 3.09E+ 11 1.55E+ 11
Natural non-renewable resources (NR)
 Water kg 4.94E− 03 [18, 37]   4.94E+ 08 3.84E+ 06
 Ground water m3 2.00E+ 04 [38] 1.34E+ 09   
 Loss of topsoil d kg 4.33E+ 07 [5, 10]    2.06E+ 11
Purchased non-renewable resources (PN)
 Diesel L 4.78E+ 07 [38] 1.74E+ 10   
 Concrete kg 6.35E+ 12 [12] 2.08E+ 11   
 Electricity kW 3.60E+ 06 [18, 38] 5.18E+ 11   
 Weaned piglet kg 2.09E+ 06 [39] 1.41E+ 11   
 Pig feed kg 1.43E+ 07 [40] 3.32E+ 13   
 Lime (CaO) kg 3.11E+ 06 [41]   3.04E+ 09 7.09E+ 09
 Small fry kg 7.98E+ 06 [42]   7.98E+ 10  
 Fish feed kg 1.26E+ 07 [43]   128.E+ 14  
 Fertilizer
 N kg 3.28E+ 01 [9, 44]    1.28E+ 11
 P 7.52E+ 01
 K 4.56E+ 01
 Pesticide kg 4.20E+ 08 [18]    1.26E+ 09
 Plough kg 1.80E+ 08 [12]    2.47E+ 11
 Sapling kg 1.44E+ 07 [18]    9.45E+ 08
Yield (Y)
 Porker kg 2.03E+ 07 [45]    1.15E+ 13
 Fish kg 7.98E+ 06 [45]    7.98E+ 12
 Fruit kg 1.89E+ 12 [18]    2.48E+ 10
  1. aSolar energy = (the average radiation of province) × (area)
  2. The average radiation of province = 17.5 MJ/(m2 day) = 6,387.5 MJ/(m2 year)
  3. bGlobal wind circulation = (0.4 J/m2/sec) × (3.15E+7 sec/year) × (area)
  4. cEvapotranspiration, chemical energy = (area) × (average rainfall) × (density) × (Gibbs free energy)
  5. Average rainfall = 2 m/year
  6. Density = 1.00E+ 06 g/m3
  7. Gibbs free energy = 4.94 J/g
  8. dNet loss of topsoil = (soil loss) × (organic matter content) = 9.5 t/ha × 2.5 ha
  9. Soil loss = 9.5 t/(ha year)
  10. Organic matter content = 20% = 0.2