Despite their differences in natural resources, Japan, European countries, and the United States managed to expand their agricultural output by up to 1.7 percent a year. Japan and the continental European countries achieved their rapid growth because yields (output per hectare of arable land) grew at about 1.5 percent a year, or roughly twice as fast as in the United States.
Most of the evidence comes from machinery stock data; though lacking detail, no other data can give so comprehensive a picture over long periods of time.8 Operations can be grouped in terms of the intensity with which they require power (or energy) relative to the control functions of the human mind (or judgment).
Early methods of weed control included mowing, flooding, cultivating, smothering, burning, and crop rotation. Though these methods are still important, other means are perhaps more typical today, particularly the use of herbicide (plant-killing) chemicals. Another technique is to introduce insects that attack only the unwanted plant and destroy it while leaving the crop plants unharmed.Agricultural mechanization has involved the partial or full replacement of human energy and animal-powered equipment (e.g. plows, seeders and harvesters) by engine-driven equipment. Most of this is tractor driven and to a lesser extent self-propelled equipment (including harvesters, sprayers, fertilizer applicators, planters and seeders). Agricultural mechanization has been pioneered in North America and Europe and more recently in Japan, and is now spreading rapidly throughout the world. Notwithstanding such progress, a significant element of human and animal powered mechanization remains, particularly in the poorer regions of the world.The scale of the investment required may be determined from comprehensive data on farm mechanization costs (see also, Expenditures and Returns). For instance, the current cost of mechanization in the UK is about 20 % of total farm input costs (Table 1). Table 1. Breakdown of farm input costs (UK inputs) (see also, Expenditures and Returns).
Crop pests include insects, fungi and weeds. It is not common to combine insecticides, fungicides and herbicides (weedkillers) but rather to apply them as individual or single formulations.The pesticide applicator sprayer is normally tractor-mounted and the tractor power-take-off shaft drives the spray pump. Such sprayer equipment (Figure 6) can also be used to apply liquid fertilizer especially where foliar applications are relevant (e.g. cereals).