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Traditional systems should be evaluated using not only criteria important to Western analysis but by using factors that are important to the traditional farmers themselves. This entails looking at productivity in conjunction with the system stability and sustainability. Traditional farmers are often willing to compromise productivity in favor of stability and sustainability. Thus apparent lower productivity can also be viewed in light of an increase in the other benefits. Crops are selected by balancing these factors rather than focusing exclusively on the one. Variation in productivity between systems can be better understood using more balanced appraisal criteria. Western farmers tend to focus much more on productivity and have achieved their goals of increased yields. Traditional farmers have also achieved their goals of balancing acceptable yields with low levels of inputs and high system stability and sustainability.
Looking at productivity more broadly, traditional systems are often considered to be less
productive than modern systems. This, of course, depends on the criteria used for comparison. Productivity measured as output per unit of human labor give larger farms the advantage as the work is often done by tractors not humans. Yield per unit energy input is much higher on traditional farms when the energy value of fossil fuel used in tractors and fertilizers is considered. In Mexican Slash and burn agriculture, 1144 hours of labor were needed to clear one ha of forest and grow 1944 Kg of corn. This translates into 6.8 million kcal or enough for 2700 kcal per day for 7 people for one year. This is a return of 128 unites of food energy per unit of human energy input. In the United States, 860 L of fuel are used to grow one ha of corn. This yields a return of 2 unites of energy output for every Kcal invested in the crop (Pimentel,1980).
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