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Peas
Peas
Scientific name:
Pisum sativum
Family:
Fabales: Fabaceae
Common names:
Garden pea / English pea / green pea / snow pea / mangetout
Pests and Diseases:
African bollworm   Anthracnose  Aphids  Ascochyta blight  Bacterial blight  Broomrape  Cutworms  Downy mildew  Fusarium wilt  Leafmining flies (leafminers)  Pea blue butterfly  Powdery mildew  Root-knot nematodes  Snails (Giant East African Snail)  Spider mites  Storage pests  Thrips  Virus diseases 
General Information and Agronomic Aspects
Geographical Distribution of Peas in Africa
Pisum sativum probably originated in South-West Asia; it is now cultivated in many temperate countries, as a cool-season crop in the subtropics and at higher altitudes in the tropics.

Peas are cultivated for the fresh green seeds, tender green pods, dried seeds and foliage. Dry seeds are used for food and feed. For food, they are cooked whole, split or ground into flour, and boiled or roasted. Large amounts are canned. Fresh peas are canned or frozen in the immature form. They are a major vegetable and commercial crop. Some cultivars are grown for their tender green pods such as snap peas (sugar snaps) and snow peas (sweet peas) mainly for export. The crop is also suitable as forage, hay, silage and green manure. Kenya export of garden peas in 2005 amounted to 2,206 tons at a value of KSh 729 million, and of snow peas 1,739 tons at a value of KSh 448 million. Total area of garden peas in 2005 was 5,313 hectares and for snow peas 1,550 hectares for both local and export market.










Nutritive Value per 100 g of edible Portion
Raw or Cooked Peas Food
Energy
(Calories / %Daily Value*)
Carbohydrates
(g / %DV)
Fat
(g / %DV)
Protein
(g / %DV)
Calcium
(g / %DV)
Phosphorus
(mg / %DV)
Iron
(mg / %DV)
Potassium
(mg / %DV)
Vitamin A
(I.U)
Vitamin C
(I.U)
Vitamin B 6
(I.U)
Vitamin B 12
(I.U)
Thiamine
(mg / %DV)
Riboflavin
(mg / %DV)
Ash
(g / %DV)
Peas, edible-podded, raw (Snowpeas) 42.0 / 2% 7.5 / 3% 0.2 / 0% 2.8 / 6% 43.0 / 4% 53.0 / 5% 2.1 / 12% 200 / 6% 1087 IU / 22% 60.0 / 100% 0.2 / 8% 0.0 / 0% 0.2 / 10% 0.1 / 5% 0.6
Green Peas cooked 84.0 / 4% 15.6 / 5% 0.2 / 0% 5.4 / 11% 27.0 / 3% 117 / 12% 1.5 / 9% 271 / 8% 801 IU / 16% 14.2 / 24% 0.2 / 11% 0.0 / 0% 0.3 / 17% 0.1 / 9% 0.9
Green Peas raw 81.0 / 4% 14.5 / 5% 0.4 / 1% 5.4 / 11% 25.0 / 2% 108 / 11% 1.5 / 8% 244 / 7% 765 IU / 15% 40.0 / 67% 0.2 / 8% 0.0 / 0% 0.3 / 18% 0.1 / 8% 0.9
Peas, mature seeds, sprouted, cooked 98.0 / 5% 17.1 / 6% 0.5 / 1% 7.0 / 14% 26.0 / 3% 24.0 / 2% 1.7 / 9% 268 / 8% 107 IU / 2% 6.6 / 11% 0.1 / 6% 0.0 / 0% 0.2 / 14% 0.3 / 17% 1.0
Peas, mature seeds, sprouted, raw 124 / 6% 27.1 / 9% 0.7 / 1% 8.8 / 18% 36.0 / 4% 165 / 17% 2.3 / 13% 381 / 11% 166 IU / 3% 10.4 / 17% 0.3 / 13% 0.0 / 0% 0.2 / 15% 0.2 / 9% 1.1
Pigeon Peas (Red Gram) cooked 121 / 6% 23.2 / 8% 0.4 / 1% 6.8 / 14% 43.0 / 4% 119.0 / 12% 1.1 / 6% 384 / 11% 3.0 IU / 0% 0.0 / 0% 0.1 / 3% 0.0 / 0% 0.1 / 10% 0.0 / 0% 1.1
Pigeon Peas (Red Gram) raw 343 / 17% 62.8 / 21% 1.5 / 2% 21.7 / 43% 130 / 13% 367 / 37% 5.2 / 29% 1392 / 40% 28.0 IU / 1% 0.0 / 0% 0.3 / 14% 0.0 / 0% 0.6 / 43% 0.2 / 11% 3.5
*Percent Daily Values (DV) are based on a 2000 calorie diet. Your daily values may be higher or lower, depending on your calorie needs.


Climatic conditions, soil and water management
Peas produce best yields and quality in cool and moist growing conditions. They grow reasonably well between 10 and 30°C with an optimum of 20°C. Temperatures above 30°C will cause poor pollination, early maturity and lower yields. Good soil moisture content is a requirement of peas, particularly at flowering and pod development. A minimum of 400 to 500 mm rainfall per cropping season (about three months) is required for growing peas without supplementary irrigation In tropical regions, the crop has to be grown above an altitude of 750 m. Peas can grow on a wide range of soils but thrive best on a well-drained soil with an optimum pH of 6 to 7.7 and a high content of soil organic matter. Time of sowing and place in the crop rotation depend on regional climate, variety and purpose of growing, whether for export or for local use. Dry peas are primarily grown as a break or catch crop in cereal rotations.

Varieties
There are two types of pea varieties based on the texture of the seed coats: Wrinkled seed type - this is due to the sugar content and the varieties are used for fresh consumption or export. Smooth seed type - these are used for dry peas and the main variety is "Black Eyed Susan".

Peas grown for fresh consumption of their seeds (green or garden peas) are harvested as soon as the pods are well-filled but the seeds are still tender and sweet. Generally, the pod is discarded after the peas are removed; but some young tender varieties have an edible pod, which are often used in Chinese dishes. Green peas are highly perishable and the sugar to starch conversion begins the moment they are picked.

Some varieties of green peas (garden peas):
  • "Green Feast"
  • "Earlicrop" - a short, early maturing variety that does not require staking
  • "Onward" - a climbing variety suitable for wet season production
  • "Alderman" - a late maturing variety that requires staking.

Snow peas or sugar peas have edible flat pods and very small seeds. They are harvested when very young, just as the seeds start to form. If not picked at this stage, they can be shelled and eaten as garden peas, but are starchier and not as sweet.

Sugar snaps are also an edible pod pea but have larger and sweeter seeds and a thicker pod than snow peas, but more delicate than the green peas. They are grown to full size and then eaten like snap beans.
Both snow peas and sugar snap peas last much longer than the green pea.
The main varieties of snow peas grown in Kenya (Kenya (Horticultural Crops Development Authority, Kenya, HCDA).

Variety Flower colour Plant height (cm) Pod size (cm) Maturity
"Mammoth Melting Sugar" White 180-200 8-12
"Dwarf Grey Sugar" Purple 70 7-8 Early maturing
"Oregon Sugar Pod" Purple 60-70 8-10 Early maturing
"Sugar Snap" White 60-70 6.5-7 Early maturing
"Toledo" White 60-65
For export crops, the exporters normally provide the seed, choosing from many imported seed varieties (not all of which are well adapted to East African climate).



Propagation and planting
Peas are sown directly on well prepared moist soils. The seeds should be planted at a depth of 2.5 cm if the soils are deep. In dry, light soils the seeds should be planted about 4 cm deep. Peas need warm soil to grow and good spacing for adequate sunlight. The seeds should be sown in double rows of 10 x 50 to 60 cm. If staked, this is done between the double rows using twigs or short-staked wires and/or strings.

In soils with low organic matter, up to 20tons/ha of manure or compost should be applied before planting, as well as up to 200 kg/ha of rock phosphate. Being a legume, peas are not responsive to nitrogen fertiliser, however it is recommended to inoculate the seeds with rhizobium (any of a genus (Rhizobium) of nitrogen-fixing bacteria found in nodules on the roots of certain leguminous plants) to encourage the plants to fix enough nitrogen from the atmosphere. Inoculating with rhizobium has been shown to increase yields by up to 100%. Mix crop residues and organic matter in the top 20cm of the soil prior to planting. This destroys current weed growth and provides a granular bed for seeding.

Husbandry
The first key need of peas is moisture. They have to be irrigated when conditions become dry. Also weed control is very essential at an early stage to reduce competition for nutrients. However, peas develop rapidly and the need for weeding is reduced when fully grown. Shallow cultivation is recommended to avoid root damage.
A suitable crop rotation program involving grains, potatoes and brassicas should be used. For good quality fresh market peas staking is recommended.

Harvesting
Green peas are ready for harvesting 8 to 12 weeks after planting. The time to harvest is determined by the appearance of the pods. For garden peas this means pods should be well filled but still smooth and green. Pod peas are harvested when pods have reached full size but before development of seeds. As the pods mature the sugar content decreases and market appeal is lost. The harvesting period may last 4 to 6 weeks. Yields vary from 1.5 tons to over 5 tons of shelled peas per hectare, with average yields of 2.5 to 3.5 tons per hectare. For the fresh market, yields of peas in pods vary from 3 tons to 10 tons per hectare, or an average of 5 or 6 tons of pods per hectare. Edible pod peas will normally yield 3 to 5 tons of pods per hectare. For fresh market whether local or export, the harvested pods are sorted and packed. Washing is not desirable as it may bruise the pods; so soiled pods are discarded during sorting along with malformed or diseased pods. Rejected peas are excellent animal feed.
For dry peas the whole plant can be uprooted when about 80% of pods have turned brown and dry. The haulm is then either left in the field or carried to a threshing place to dry completely, after which the peas are threshed and winnowed. For storage of dry peas please see chapter on storage pests (click here).

Information on Pests
Information on Diseases
Information Source Links
  • Agricultural Information Center (2003). Fruits and Vegetables Technical handbook, revised edition.
  • Alan McNab (2007). Pea Diseases. Vegetable Disease Identification. Department of Plant Pathology, Penn State University. http://plantpath.psu.edu
  • CABI (2005). Crop Protection Compendium, 2005 Edition. © CAB International Publishing. Wallingford, UK. www.cabi.org
  • East African Seed Co. Ltd. Africa's Best Grower's Guide www.easeed.com
  • Green peas. www.agriculture.kzntl.gov.za
  • Hagedon, D.J. (Ed) (1984). Compendium of Pea Diseases. American Phytopathological Society Publication. ISBN-13: 978-089054602.
  • Horticultural Crops Development Authority (HCDA). Export Crop Bulletin: No 1. June 1996. Snowpeas (Pisun sativum). Leguminosaceae.
  • Mark Gaskell. Edible-pod pea production in California. Vegetable and Information Center. Vegetable Production Series. ISBN: 978-1-60107-024-1. www.anrcatalog.ucdavis.edu
  • Ministry of Agriculture (2006). Economic Review of Agriculture. Republic of Kenya.
  • Muehlbauer, F.J.,Tullu, A. (1997). New crop fact sheet. Pisum Sativum L. www.hort.purdue.edu
  • Myers, J.R., Colt, W.M., Swanson, M.A. (1994). Beans and Peas. A Pacific Northwest Extension Publication, Idaho, Oregon, Washington. www.cals.uidaho.edu
  • NSF Center for Integrated Pest Managment. Crop profile for peas (green) in Idaho
  • Nutrition Data www.nutritiondata.com.
  • Ohio State University. Ohio State University Extension Fact Sheet Horticulture and Crop Science: www.ohioline.osu.edu
  • PIP. Technical Itinerary Pea. With technical collaboration of Louis Labuschagne of Real IPM. PIP-COLEACP, Brussels, Belgium. www.coleacp.org
  • Purdue University. Center for New Crops & Plant Products. www.hort.purdue.edu
  • Sherf, A.F., MacNab, A.A. (1986). Vegetable Diseases and Their Control. A Wiley-Interscience Publication. ISBN: 0 471 05860 2.
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