I should have also mentioned that they are not so difficult to manufacture locally. In Thailand where there about 1.5 million AFPs they have 4-5 large scale manufacturers (making 1000s / year) as well as 100 or more local manufacturers (who make less than 100 / year?). Various plans/schematics available on internet or through CIMMYT and IRRI. Similarly there are about half million in Vietnam many also locally reproduced by artisans. Costs in Thailand run from 180 USD for 6-8 HP 5 inch dia models to 200-350 USD for 6-8 inch diameter and 25 foot long models (to reach laterally down into a river bed or canal). Most are powered by 2-wheel tractors or stand alone diesel or petrol engines.
Published by S Justice, Agricultural Mechanization at International Center for Maize and Wheat Improvement (CIMMYT)
I should have also mentioned that they are not so difficult to manufacture locally. In Thailand where there about 1.5 million AFPs they have 4-5 large scale manufacturers (making 1000s / year) as well as 100 or more local manufacturers (who make less than 100 / year?). Various plans/schematics available on internet or through CIMMYT and IRRI. Similarly there are about half million in Vietnam many also locally reproduced by artisans. Costs in Thailand run from 180 USD for 6-8 HP 5 inch dia models to 200-350 USD for 6-8 inch diameter and 25 foot long models (to reach laterally down into a river bed or canal). Most are powered by 2-wheel tractors or stand alone diesel or petrol engines.