Homework SourseIn Table 3 what was the human energy subsidy to the lawn eco
In Table 3, what was the human energy “subsidy” to the lawn ecosystem, that is, how many kcal/lawn/year of direct human input (as labor) were there? How does this compare to the kcal “subsidy” of fertilizer and gasoline for the lawn mower?
Labor male
Labor female
3h 50 min
3h 30 min
0.356 kcal/kg per 10 min
0.356 kcal/kg per 10 min
532.2
249.2
Labor male
Manure
Chemical fertilizer
27.5 min
10.7 kg
3.63 kg
0.564 kcal/kg per 10 min
79.70 kcal/lb
1,382.15 kcal.lb
100.8
1,800.9
11,0572.2
Labor Male
Gasoline
4h 58 min
4.73 liters
0.979 kcal/kg per 10 min
36,225 kcal/gal
1,983.9
45,281.3
Labor Male
Seed
6.5 min
326.6 g
0.564 kcal/kg per 10 min
1,800 kcal/lb
23.8
1,293.7
| Task | Total time | energy factor | kcal/yr |
| Raking (labor) | 7h 26 min | 0.686 kcal/kg per 10 min | 1988.7 |
| Irrigation | |||
| Labor male Labor female | 3h 50 min 3h 30 min | 0.356 kcal/kg per 10 min 0.356 kcal/kg per 10 min | 532.2 249.2 |
| H20 (source lawn) | 340.82 m^3 | 413.1 kcal/m^2 | 140,792.7 |
| Fertilizing | |||
| Labor male Manure Chemical fertilizer | 27.5 min 10.7 kg 3.63 kg | 0.564 kcal/kg per 10 min 79.70 kcal/lb 1,382.15 kcal.lb | 100.8 1,800.9 11,0572.2 |
| Lawn Mowing | |||
| Labor Male Gasoline | 4h 58 min 4.73 liters | 0.979 kcal/kg per 10 min 36,225 kcal/gal | 1,983.9 45,281.3 |
| Reseeding | |||
| Labor Male Seed | 6.5 min 326.6 g | 0.564 kcal/kg per 10 min 1,800 kcal/lb | 23.8 1,293.7 |
| Miscellaneous labor | 16 min | 0.686 kcal/kg per min | 71.3 |
| Total | 205,175.7 |
Solution
what was the human energy “subsidy” to the lawn ecosystem, that is, how many kcal/lawn/year of direct human input (as labor) were there
1988.7
How does this compare to the kcal “subsidy” of fertilizer and gasoline for the lawn mower?
100.8 +45,281.3 = 45382.1
