Skip to main content
Engineering LibreTexts

13.2.5.2: Complete the Excel Spreadsheet

  • Page ID
    48694
  • Instructions

    Read the table below very carefully and follow the instructions to complete the spreadsheet (see the previous page for spreadsheet download) using the Gallon Gasoline Equivalents per Hectare given in table 10.2.1 below.

    Instructions for lines 1.1 to 1.15 of Excel table. This is for potatoes produced in the Andean smallholder agriculture system.

    The table below provides instructions for filling in the data needed for the LCA of energy use by Andean smallholder agriculture based on the agricultural practices in these systems. You will need the table of values for the two different systems (see table 10.2.1 below, see link below to download or use the online version)

    Line Number in Excel Table What to enter into the spreadsheet -- you are entering 'Gallon Gasoline Equivalents' of energy
    A.1 Look up the smallholder tillage energy value (LEFT side of table 10.2.1 below) in the table and enter it.
    A.2 Look up the smallholder hand labor energy value on the LEFT side of table 10.2.1 below and enter it -- it is considerable because many operations like weeding and hilling up potatoes to make them yield better are done by hand.
    A.3 Manure energy is not counted as it is a by-product of other animal uses on the farm such as meat, wool, and traction uses, so enter zero.
    A.4 Irrigation - as explained on the right side of table 2, this does not use energy even when it is used, because it is usually gravity-fed.
    A.5 & A.6 This value has been entered to simplify the exercise, but please read this explanation: small amounts of fertilizers are used by smallholders, so use a value of 10 kg per Ha of nitrogen (N) and phosphorus (P) in fertilizers. The values in the table happen to be given just "per 10 kg of nutrient", so we have multiplied the figure in the table (4.9 gallons gasoline per 10 kg N) by 10 kg, which gives 4.9 gallons gasoline and 1.0 gallons of gasoline for N and P respectively. These are already filled in.
    A.7 Potassium fertilizer is not used, so enter zero.
    A.8 Energy is required to produce seed, in essence, the energy value from this LCA for the preceding crop multiplied by the seeding rate of potatoes. Enter this value into the excel table.
    A.9 Fungicide might be one chemical input that would be used in the Andes by smallholders to combat late blight and other common potato diseases, so we include it here. Enter the value shown in the table into your LCA excel table.
    A.10 This cell is summed automatically. You do not need to enter anything, but you should note it for comparison and checking with other findings of the LCA. The energy inputs for all production activities are summed automatically by the spreadsheet, in gallons gasoline equivalent per Ha. At right it is also given per 1000 kg of potatoes produced, assuming a yield of 10,000 kg/ha fresh weight of potatoes which is a medium to good yield for smallholders in the Andes.
    A.11 This cell is summed automatically and you do not need to fill in. Here the energy inputs are summed as in A10 but representing ONLY those energy sources that represent fossil fuel inputs (e.g. fertilizer, fungicide)
    A.12 Transport distance. For smallholder systems in the Andes, about half the crop might be transported about 100 km as an average. Half the crop being sold is already factored into the calculations for energy used (A13).
    A.13 This cell is calculated automatically. The transport energy required to transport half the crop to market is calculated by the spreadsheet. The other half is assumed to stay on the farm for home consumption.
    A.14 This represents a total of energy inputs for production plus transport to market per land area (Ha); at right on line 13, it is given per kg of potato produced.
    A.15 This represents only the fossil fuel energy required for production plus transport

    When you have entered all the values for the smallholder system, you will see the LCA results for production only, and production plus transport summarized at right in column E of the Excel spreadsheet.

    Instructions for lines 2.1 to 2.17 of the excel table, LCA for industrial agriculture:

    Use the instructions below to fill in the second LCA for industrial agriculture:

    Line Number in Excel Table What to enter into the Excel Table -- you are entering 'Gallon Gasoline Equivalents' of energy
    B.1 look up the industrial agriculture value for tillage energy value (RIGHT side of table 10.2.1 below) in the table and enter it.
    B.2 look up the industrial agriculture hand labor energy value in table 10.2.1, RIGHT side, and enter it (hand labor energy is very small because most operations have been mechanized)
    B.3 We assume manure is not used on these potato farms. They tend to be large farms and not necessarily close to sources of manure, so we have already entered zero here.
    B.4 Irrigation: Enter the value on the right side of the table if you wish to model the case of Colorado or other regions where potatoes are grown in dry climates. Otherwise, you should enter zero because we assume that potatoes use only rainfall, and energy is not required to irrigate them.
    B.5 Nitrogen fertilizer: 180 kg/ha of nitrogen is applied to potatoes. The value in the table below gives an energy value in gallons of gasoline per 10 kg of N, so you should calculate 180/10= 18 and multiply it by the value in the table, equal to 18 x 4.9 or 88.2 gallons gasoline. This value has been entered in the excel table, and you will use the phosphorus and potassium fertilizer energy equivalents to enter them.
    B.6 Repeat the process above for N fertilizer, but using the P fertilizer value from the table and 120 kg of P/Ha as the application rate of phosphorus to potatoes (remember to divide this P rate by 10)
    B.7 Repeat the process above for N fertilizer, but using the K fertilizer value from the table and 200 kg of P/Ha as the application rate of phosphorus to potatoes (remember to divide this P rate by 10)
    B.8 Energy is required to produce seed, in essence, the energy value from this LCA for the preceding crop multiplied by the seeding rate of potatoes. This value is 35.4 and has been entered into the excel table.
    B.9 Fungicide is applied to combat fungal diseases that are common in potato-growing regions, and ensure high yields that justify the relative expensiveness of growing in this intensively managed crop.
    B.10 Insecticide is used to manage insect pests of the crops. These have an energy cost of manufacture, transport, and driving through the field on a tractor to apply them. Enter the value from the right side of the table
    B.11 Herbicide is used to control weeds in the potato crop. These have an energy cost of manufacture, transport, and driving through the field to apply them. Enter the value from the right side of the table.
    B.12 This cell is summed automatically. You do not need to enter anything, but you should note it for comparison and checking with other findings of the LCA. The energy inputs for all production activities are summed automatically by the spreadsheet, in gallons gasoline equivalent per Ha. At right it is also given per 1000 kg of potatoes produced, assuming a yield of 10,000 kg/ha fresh weight of potatoes which is a medium to good yield for smallholders in the Andes.
    B.13 This cell is summed automatically and you do not need to fill in. Here the energy inputs are summed as in A10 but representing ONLY those energy sources that represent fossil fuel inputs (e.g. fertilizer, fungicide)
    B.14 Transport distance: For potatoes in New York or Michigan (examples of eastern states in the U.S.) choose 200 km. For potatoes in more remote Colorado, the mean transport distance is approximately 700 km (on average), so enter this in the excel table. The energy for transport is calculated automatically in the next cell below.
    B.15 This cell is calculated automatically as the energy needed to transport the entire crop to ma et, since this is exclusively a cash crop by contrast to the smallholder system.
    B.16 This represents a total of energy inputs for production plus transport to market per land area (Ha). To the right on row 33, it is given per kg of potato produced.
    B.17 This represents only the fossil fuel energy required for production plus transport

    Also, in the case of the industrial system, the yield that is present in the excel table is a good deal higher than that shown for the Andean system, at 35,000 kg potatoes per Ha. This can be traced to a number of factors: less limiting fertility provided by higher nutrient inputs, different varieties specialized for high yields as well as different globalized market characteristics in North America, reduced pest and weed pressure, and better overall quality of soil resources where potatoes are grown, which may include flatter, deeper, and better-drained soils.

    Table 10.2.1. Data table of energy equivalent values, drawn from Pimentel and Pimentel, 1995. Food, Energy, and Society. Note: if it easier to display the table in a separate window or print it out you can download the table. Some updates have been made to the information to reflect more recent practices and fertilizer application rates. Industrial potato figures are based on the New York Potato production, while developing country figures are based on figures for similar ox-drawn tillage systems in highland Mexico and authors’ estimates of transport distances in the Andes and differences in embodied energy for seed production. Note that fertilizer energy amounts are given per 10 kg of fertilizer.
    LCA Category Smallholder agriculture system description Energy input for smallholder agriculture, in Gallon Gasoline Per Hectare equivalents Industrial agriculture description Energy input for industrial agriculture, in Gallon Gasoline Per Hectare equivalents
    1.Tillage and field operations Energy input of oxen for plowing 16.1 Tractor fuel use and other machinery energy use on-farm 146
    2. Hand labor Driving traction animals and several hand operations (hilling, weeding, harvesting) 6.4 Human operation of machinery and occasional direct field operations 0.05
    3. Irrigation Irrigation is usually gravity-based if used at all. none Choose this value ONLY if you decide to do an LCA for Colorado potato production - all other areas use zero irrigation. 137
    4. Nitrogen (N) fertilizer Manufacture of N fertilizer per 10 kg fertilizer 4.9 Manufacture of N fertilizer per 10 kg fertilizer 4.9
    5. Phosphorus (P) fertilizer Manufacture of P fertilizer per 10 kg fertilizer 1.0 Manufacture of P fertilizer per 10 kg fertilizer 1.0
    6. Potassium (K) fertilizer Manufacture of P fertilizer per 10 kg fertilizer 0.5 Manufacture of P fertilizer per 10 kg fertilizer 0.5
    7. Seed Energy embodied in seed production 2.3 Energy embodied in seed production (in an industrial system) 35.4
    8. Insecticide none -- Energy embodied in insecticide production and application 87.6
    9. Herbicide none -- Energy embodied in herbicide production and application 58.5
    10. Fungicide Energy embodied in fungicide production 12.7 Energy embodied in fungicide production and application 12.7
    11. Electricity none -- Electrical equipment and lighting for processing potatoes 4.4
    12. Transport Energy to transport half of one-hectare yield to wholesale market or processor (for e.g. 100 km distance) - this will be calculated by the spreadsheet. 7.8 Energy to transport the whole yield of industrially produced potatoes to market. 72.2
    • Was this article helpful?