Suitability Rating Criteria for Coffee
A publication with details on the production of coffee in the state of Hawaii is presented by Bittenbender and Smith (2004), including production in Kona on the island of Hawaii. According to these authors, the climatic requirement of coffee is a mean annual temperature between 59º and 73º F and a mean annual rainfall of greater than 59 inches.
Bittenbender and Smith, furthermore, mention that coffee is produced in Hawaii where annual rainfall ranges from 30 to over 100 inches, and that the optimum range is considered to be 60 to 85 inches. The rainfall distribution pattern is also cited as being important to the different phasesof the coffee growth cycle. A short dry period during the coldest part of the year was favored to be associated with a more favorable cropping cycle, flower bud growth, and dormancy prior to flowering.
Physical land evaluation includes not only the climatic factors but also the soil and land characteristics. Table 1, the rating criteria of the Natural Resources Conservation Service (formerly, Soil Conservation Service), USDA, will therefore be used to supplement the rainfall and temperature requirements. The table is modified to include the soil acidity which is critical for coffee.
|Table 1. Soil suitablity rating criteria for rainfed coffee (modified)|
|Criteria||Well suited||Moderately suited||Poorly suited||Reasons|
|Bedrock depth||>40 inches||20-40 inches||<20 inches||Anchor, leaching|
|Stoniness||None to hinder cultivation||Enough to hinder cultivation||Enough to prevent cultivation||Cultivation, workability|
|Drainage||Well-drained||Moderately-drained||Poorly-drained||Pathogens in wet soils, decreased equipment trafficability in wet soils|
|Soil pH||5.5 - 7.0||5.0 - 5.5,
7.0 - 7.5
|<5.0, >7.5||Mn toxicity at pH <5.6 in soil with high Mn/Ca ratio, e.g.Wahiawa soil|
|Rainfall (rainfed)||60-100 inches||40-60 inches,
|Air temperature||>65º F||62-65º F||<62º F||Optimal growth|
* Rate one class better if mineral soil over fragmental aa lava within 30 inches.
**Rate one class better if organic soil over fragmental aa lava.
Source: NRCS, USDA. 2001. Unpublished soil suitability rating criteria for unirrigated coffee.
- Original reference shows level of concern (little, moderate, high) rather than suitability.
- Stoniness is substituted for coarse fragments in upper root zone).
- Drainage classes have been simplified as well-drained, moderately well-drained, and poorly-drained.
- Rating for soil pH was added based on the chemistry of acidic soils with high Mn/Ca ratio soil, such as Wahiawa soil series (N. Hue, personal communication, 2001).
- In the final rating, intermediate classes are used with this three-class system; that is, the well to moderately-suited class, the moderately to poorly-suited class, the poorly to not-suited class, and the not-suited class.