Farming as a System: Inputs, Processes, and Outputs

Farming as a system means viewing a farm as a set of linked parts: inputs (such as seeds, labor, water, soil and capital) are changed by processes (such as plowing, planting, feeding and harvesting) into outputs (such as crops, milk, meat and profit), with feedback from the outputs affecting the next cycle. In brief: inputs can be physical (climate, soil, relief) or human and economic (labor, machinery, fertilizer, money, knowledge); processes are the activities on the farm; outputs are the products and the waste. A wheat farm, a dairy farm and a rice paddy all follow this pattern but with different inputs and processes.

The systems approach helps geographers compare very different farms using the same framework and see how a change in one part affects the rest. This guide explains inputs, processes, outputs and feedback, applies the model to three farm types, compares them in a table, works through profit and productivity calculations, outlines the history of the idea and corrects common mistakes.

What are the inputs of a farm?

Inputs are everything that goes into the farm.

• Physical inputs: climate (temperature, rainfall, sunshine), soil type and fertility, relief (slope and altitude) and natural water supply.
• Human and economic inputs: labor, machinery, buildings, seeds, animals, fertilizer, pesticides, fuel, irrigation water, money for loans and the farmer’s skill and knowledge.
• Other inputs: government subsidies, land ownership and access to markets, roads and technology.

What are the processes?

Processes are the activities that turn inputs into outputs. On an arable farm, they include plowing, sowing, fertilizing, weeding, spraying, irrigating, harvesting and storing. On a livestock farm, they include grazing, feeding, breeding, milking, shearing and caring for animal health. Processes also include management decisions, such as which crop to plant, when to harvest and how to sell the produce. The processes are shaped by the type of farm, the available technology and the weather.

What are the outputs and feedback?

Outputs are the products of the farm: crops such as wheat or rice, animal products such as milk, meat, eggs and wool, and income or profit. There are also by-products and waste, such as straw, manure and surplus, as well as environmental effects such as soil erosion or water pollution. Part of the output is consumed by the farm family (in subsistence farming) or sold, and the income is used to buy new inputs. This return flow is feedback: a good harvest and profits allow the farmer to invest in better seed or machinery next year (positive feedback), while a poor harvest and debt may force a reduction in inputs and lower output the following year. Wheat residues may also be returned to the soil as an input.

How does the system look on different farms?

On a large wheat farm in the Canadian Prairies, key inputs are fertile soil, large machines, fertilizer and capital, the processes are mechanized sowing and harvesting, and the output is grain sold to world markets. On a dairy farm in Ireland, the inputs include grass from a mild, wet climate, cows, milking equipment and feed; the process is grazing, feeding and milking; and the outputs are milk, calves and manure. On a rice paddy in Vietnam, key inputs are monsoon rain and river water, fertile alluvial soil and a large amount of family labor, the processes are transplanting seedlings by hand and flooding the fields, and the output is rice, mostly eaten by the family and sold locally.

Farm systems compared

Worked example: yield, profit and productivity

All figures are hypothetical and chosen to show how the system’s parts are measured.

1. Output: a farm of 200 hectares produces wheat at a yield of 5 tonnes per hectare. Total output = 200 × 5 = 1,000 tonnes.
2. Revenue: at a price of 220 per tonne, the revenue is 1,000 × 220 = 220,000.
3. Costs (inputs): seed 12,000, fertilizer 38,000, chemicals 15,000, fuel and machinery 35,000, labor 40,000 and other costs 20,000. Total costs = 12,000 + 38,000 + 15,000 + 35,000 + 40,000 + 20,000 = 160,000.
4. Profit: 220,000 − 160,000 = 60,000, or 60,000 ÷ 200 = 300 per hectare.
5. Labor productivity: if 2 full-time workers run the farm, each produces 1,000 ÷ 2 = 500 tonnes of wheat per worker.
6. Feedback: if the farmer reinvests 20,000 in better seed that raises the yield by 10% to 5.5 tonnes per hectare, output becomes 200 × 5.5 = 1,100 tonnes, and revenue rises by 100 × 220 = 22,000, which is a return of 22,000 ÷ 20,000 = 110% in the first year (before extra harvest costs).

How did farming systems develop?

The idea of seeing a farm as a system comes from general systems theory, which developed in the mid-20th century, and was applied to geography from the 1960s. Earlier, Johann Heinrich von Thünen, a German economist, studied how distance to the market affects the type of farming around a town in his work of 1826. Geographers later used input-process-output diagrams to compare farms around the world, and today, the systems approach is combined with data from satellites and sensors to model farms and food systems at all scales.

Which mistakes are common?

Mistake 1: Mixing up inputs and outputs

Seeds, labor and fertilizer are inputs. Crops, milk and profit are outputs. A crop residue returned to the soil can be both an output of one cycle and an input of the next.

Mistake 2: Forgetting the physical inputs

Climate, soil and relief are inputs, not just background. They limit what the farmer can do.

Mistake 3: Listing processes as outputs

Harvesting is a process. The harvested crop is the output.

Mistake 4: Ignoring feedback

Income and experience influence later inputs, so the system changes from year to year.