Crop Suitability


To assess the suitability of the land for selected crops the soil attributes and land qualities are compared with the individual crop requirements for optimum growth. A manual approach was taken for matching soil map units and crop requirements with land qualities. This approach produced robust results and gave sensible estimates for the crop suitability of the 50+ crops for the 193 soil map units.



Crops Rated

Crop suitability ratings were determined for each soil map unit defined for Tonga for the following crops:

Root crops

Cassava, Giant Taro (Kape - Alocasia), Kava, Kumala, Potato, Taro (Talo Futuna - Xanthosoma and Talo Tonga - Colocasia) and yam


Beans, Carrot, Cabbage, Eggplant, Lettuce, Pumpkin, Squash, Sweet Corn, Tomato and Zucchini

Tree crops

Breadfruit, Citrus, Coconut, Coffee, Guava, Mango, Noni, Paper Mulberry

Other crops

Banana, Papaya, Peanut, Pineapple, Vanilla, Watermelon


Crop Suitability Class rating system

Class 1 Highly suitable

Without significant limitations.

Class 2 Moderately suitable

Suitable but has limitations that reduce productivity or increase the inputs needed to sustain productivity.

Class 3 Marginally suitable

Limitations so severe that benefits are reduced and/or the inputs needed to sustain production are increased so that this cost is only marginally justified.

Class 4 Not suitable


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