21 



of a common denominator which is usually money ('^8, ^9. 105, l20, 132). 

 Levels or return are usually measured and expressed in terms of returns 

 to physical resources such as land ($/ha) , irrigation water or rainfall 

 ($/inch) or returns to purchased and applied production inputs such as 

 fertilizer ($/kg) or labor ($/hr) . Price (132) stated that rates of 

 return to resoiarces should be regarded as secondary criteria after net 

 returns criteria are met. Measuring rates of return to resources is 

 useful if a farmer is interested in profit maximization. A farmer will 

 achieve this goal through maximizing return to his limiting resource 

 (120). For example, a farmer with large amounts of available labor 

 compared to cash will adopt cropping patterns that produce high rates 

 of return to cash (132). Conversely, an appropriate cropping pattern 

 in an area characterized by a marked shortage of labor at certain times 

 of the year will maximize returns per unit of labor (120). 



The rate of retuom to both physical and applied resources is 

 affected by fainner's crop management interacting with physical, biolo- 

 gical, and socio-economic factors. Hence, motivation and production 

 decisions of farmers are influenced by these factors (24). For example, 

 small-scale farmers in Taiwan intercrop tomato for processing with mango 

 to utilize more fully their land and family labor resources. Production 

 practices for tomato intercropped with mango are similar to those in 

 the monocrop and intercrop with sugarcajie, but adverse physical and 

 environmental factors reduced yields. Net returns and farm income were 

 much lower when tomato was intercropped with mango than when tomato was 



a monocrop or intercropped with sugarcane (24) , Since there was no 

 close relationship between fertilizers applied ajid yield in tomato 



