Zone I
This zone has no direct importance in agricultural production other than being the source of rain and some rivers/streams. It is confined to mountains and immediate surrounding such as Mt. Kenya and Mt Elgon.

Zone II
This zone is generally restricted to the highlands of Kenya between 1980 and 2700 m and occurs as a forest or open grasslands. This zone is found in the surroundings of Mt Kenya (parts of Meru, Embu, Kirinyaga and Nyeri), isolated parts of the Rift Valley around Mau and Abadares mountains (e.g. around Kericho and Nyahururu respectively) and the surrounding of Mt Elgon (e.g. around Kitale and Webuye). The minimum rainfall is 1000mm. The main grasses are Pennisetum clandistenum (Kikuyu grass), Themeda triandra (Red oats), Andropogon chrysostachyus, Andropogon pralonsia, Exotheca abysinica, Digiteria scalaram, Eragrostis lascantha, Seteria sphacelata, Pennisetum catabasis and Sporobolus filipes. The legumes include Trifolium johnstoni, Medicago sativa (Alfalfa or Lucerne), Sesbania sesban and Leuceana leucusephala.

Zone III
This zone occurs mainly at elevations between 900-1800 m with a annual rainfall between 950 and 1500 mm. Trees are numerous here and are of somewhat shorter stature than in Zone II. This zone is the most significant for agricultural cultivation and several legume fodders are found here in crop-livestock systems. It is also the most resettled by humans. It occurs in the vast parts of Nyanza, Western and Central provinces, a good proportion of Central Rift-Valley, (Nandi, Nakuru, Bomet, Eldoret, Kitale) and a small strip at the Coast province. The major grasses are Hyperenia and Cymbopogon, Themeda triandra, Panicum maximum, Seteria Sphacelata, Sporobolus pyramidalis, Bracharia brizantha, Bricharia siluta, Chloris gayana and Cynodon dactylon.