de Bie, Kees 
  
  
  
to-date technology since responses provide exponential returns. The management 
requirements of mango orchards demand not only that farmers are knowledgeable 
and experienced but also that a well-informed extension service collaborates 
closely with researchers. 
1. Study objective 
Since the mid-seventies, farmers in Phrao planted a large number of orchards with 
mango as the most prominent fruit tree. Sales continued to be profitable and 
farmers made great efforts to improve their orchard’s productivity. However, lack 
of experience led to a “trial and error” type of management (Wangchuk 1992) that 
can partly be attributed to a disparity in access to knowledge. This is caused by 
the limited attention of extension services for some settler categories (Marzan 
1992) and by problematic technology transfer to settlers with a low level of 
education (Polprasid 1986). The above resulted amongst others in a rather 
random establishment of orchards with varying success rates (Figure 1). Areas 
involved concern mostly resettlement schemes managed by the Phrao 
Cooperative Land Settlement Project. Planning of the scheme was based on land 
allocation on an ‘equal area’ principle and not on evaluation of the suitability of 
land for anticipated land uses (Schapink 1992). Teshome (1992) reports that 
gross-margins from fruit crops are up to ten times those obtained from other crops 
in Phrao. Dissimilar gross-margins and dissimilar access to credit that relates to 
the presence of a land title deed created dissimilar access to inputs such as 
irrigation water, NPK and pesticides (Polprasid 1986). The costs involved in 
planting an orchard, the long waiting period till returns can be expected, and the 
‘trial and error’ approach add up to a considerable risk to fruit-farmers. In Phrao, 
pests like stemborers (caterpillars?) that affect mango trees to the extent that 
several orchards were being uprooted in 1993 amplify these risks. However, if 
successful, orchards provide a lasting high income (Waramit 1992). 
Comparative Performance Evaluation (CPE) allows studying the impact of 
differences in land supplying conditions and management on the productivity of 
orchards and makes the ‘trial and error’ approach redundant. 
2. Study area 
Phrao is located in North-Thailand, 80 km from Chiang Mai, and measures 1,339 
kn*. It has a population of 50,487 scattered over 93 villages. The region consists 
of an oval floodplain (alluvial soil complex) surrounded by terraces (under rainfed 
agriculture) and mountains (national park); see Figure 1. In North Phrao, only 34 
orchards existed in 1977 (within the 200 km? studied®). In 1984 their number had 
  
1 Land titles were held for 54 of the 64 orchards surveyed. 
Most likely larvae of the Cerambycid beetle ssp. called Rhytidodera simulans (FAO 1986”). 
Counts are based on two sets of aerial photographs (1977 at scale 1:15.000 and 1984 at scale 
1:20.000); field verification in 1993. 
3 
  
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International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.