There are green and yellow varieties of split peas.
(a) Bleached split peas. Split peas of green-colored varieties which are bleached distinctly yellow in color or split peas of yellow-colored varieties which are bleached distinctly green in color. (b) Classes. The following three classes: (1) Green split peas. Split peas from smooth green dry pea varieties. (j) Heat-damaged split peas. Split peas which have been materially discolored and damaged by heat. (k) Poor color split peas. Split peas that in mass are distinctly off color from the characteristic color of the predominating class as a result of age or any other cause. Yellow or green are the common colors of split peas. A quick glance at a seed catalog or a rack of seed packages at a garden store reveals many different types of peas to plant in gardens.  Split peas from smooth yellow dry pea varieties. (c) Contrasting split peas. Split peas which are of a color contrasting with the predominating class of split peas. Bleached split peas of the predominating class shall not be considered as contrasting split peas. (j) Heat-damaged split peas. Split peas which have been materially discolored and damaged by heat. (k) Poor color split peas. Split peas that in mass are distinctly off color from the characteristic color of the predominating class as a result of age or any other cause. Split peas cook relatively quickly. Unsoaked peas take from 1 to 2 hours of simmering; soaked peas take about 40 minutes. Also, the only difference between yellow and green split peas is color. 1  Split peas absorb lots of water as they cook, so check the soup often and add liquid as needed. 2  The peas only need to be cooked until they are tender. 3  If you like really silky soup, take the extra step of pureeing the peas once they have softened Beans, split peas and lentils (often referred to as “pulses”) are the edible seeds of legume plants. They are a great low-fat source of protein and are high in fiber. This post covers how to cook dried and canned pulses, and provides links to some great recipes. Split peas and lentils do not require soaking. They take a short amount of time to cook (about 20 minutes to 1 hour depending on the recipe). Dried beans on the other hand, do require soaking for at least 4 hours. Split peas are field peas, which are a variety of yellow or green peas grown specifically for drying. When these peas are hulled and then split in half along the natural seam, they become split peas, which encourages faster cooking and eliminates the need to presoak.  In markets, both the green and the yellow varieties of split pea are found in their respective selections, bagged by color. These two colors reflect some of the work of Gregor Mendel, who studied the inheritance of seed color in peas. The green phenotype is recessive to the yellow one. Yellow split peas are used to make a sweet snack in Beijing cuisine. Wandouhuang (豌豆黄) is a sweetened and chilled peas pudding, sometimes flavored with osmanthus blossoms and dates. In Europe, the Greek  Fava  is a dish made with yellow split peas pureed to create an appetizer or meze. Green and yellow split peas are commonly used to make pea soup or split pea soup, and sometimes pease pudding, which was commonly prepared in Medieval Europe. In north India, they are generally known as matar ki daal, sometimes used as a cheaper variation for the very popular chhole on stalls offering it. Yellow split peas are used to make a sweet snack in Beijing cuisine. Wandouhuang (豌豆黄) is a sweetened and chilled peas pudding, sometimes flavored with osmanthus blossoms and dates. In Europe, the Greek  Fava  is a dish made with yellow split peas pureed to create an appetizer or meze. These are dried peas that have been mechanically split along a natural seam, so that they cook faster. You can buy either green or yellow split peas. Either color can be used to make split pea soup. There are tons of variations and ways to make split-pea soup your own. Split peas and lentils do not require soaking. They take a short amount of time to cook (about 20 minutes to 1 hour depending on the recipe). Dried beans on the other hand, do require soaking for at least 4 hours. Yellow-Green Split Pea Soup. Using yellow and green split peas makes a stunning presentation, but the soup is just as tasty with only one color pea. Pick your favorite color and use 1 1/2 cups peas; then there's no need to divide the ingredients and cook them in separate pans. 
http://www.gipsa.usda.gov/fgis/standards/splitpeas.pdf http://homeguides.sfgate.com/difference-between-split-pea-sweet-pea-58973.html http://www.gipsa.usda.gov/fgis/standards/splitpeas.pdf http://dish.allrecipes.com/split-pea-soup/ http://startcooking.com/how-to-beans-split-peas-and-lentils http://www.thekitchn.com/whats-the-difference-between-split-peas-and-lentils-word-of-mouth-214986 https://en.wikipedia.org/wiki/Split_pea https://en.wikipedia.org/wiki/Split_pea http://startcooking.com/how-to-beans-split-peas-and-lentils http://www.myrecipes.com/recipe/yellow-green-split-pea-soup
what color are split peas