Green Gram Farming In Kenya, A Growers Guide

Green gram (Vigna radiata L.) also known as Mung bean and Ndengu in Kiswahili is one of the potential food and cash crop pulses that have been observed to perform well in the arid regions of Kenya. The crop is commonly grown in central, south Nyanza, eastern and coastal regions. The grain is characterized by good digestibility, flavour, high and easily digestible protein and absence of any flatulence.

Its seed contains contain approximately 374 Kcal, 23.9% protein, 1.2% fat, 16.3% dietary fiber, 4.5-5.5% ash, 63% carbohydrates on dry weight basis. It is also a crucial source of vitamins A and B complex. It also contains generous amounts of micro-nutrients such as iron and zinc which are deficient in diets among the poor, particularly pregnant women and children in Africa.

Green Gram Farming In Kenya.

In Kenya, pulses are the second most important staple food commodity after cereals. Pulses are an essential source of livelihood for millions of Kenyans and can play an important role in mitigating malnutrition challenges among Kenyans. Some of the most important pulses in Kenya include the common dry beans, green grams and pigeon peas. In addition, Pulses are rich in proteins, energy, starch, and essential minerals and compounds, which are essential for healthy life.

Green gram in Kenya is mainly grown by smallholder farmers, where it is often cultivated in unfavourable conditions and with minimum inputs. The production is severely constrained by low yielding varieties, disease and insect pests, variable climatic and soil conditions, lack of access to improved varieties, long maturing varieties and poor crop management practices.

Arid and Semi-Arid lands (ASALs) constitute approximately 89 percent of Kenya’s land mass where green grams can do well compared to other traditional crops such as maize and beans. Several counties such as Meru, Kitui, Kirinyaga, Embu, Makueni and Machakos have recently fast-tracked widespread farming of green grams as a cash crop. For instance, the Meru County Government has a campaign dubbed “Ndengu Pesa” while in Kitui County it is called “Ndengu Revolution”.

While Kenya has recently popularized the production of green grams, the exports of pulses are still depressed and this is despite the huge market prospects in the world and evidence indicating that Kenya has a great potential to grow green grams in large quantities for exports purposes.

Ecological requirements on green gram farming in Kenya

Altitude

Green gram perform best at altitudes between 50-1600 masl At higher elevations, of more than 1800 m, it has very poor pod set.

Rainfall requirement on green gram farming

Green gram is drought tolerant with rainfall requirements ranging between 350-700 mm per annum. Adequate moisture is required from flowering to early and late pod fill to ensure good yield. Late planting which coincides with flowering during the high temperature-low moisture season, reduce yield.

High humidity and excess rainfall late in the season may result in disease challenges and harvesting losses due to delayed maturity. Heavy rainfall and cool temperatures lead to increased vegetative growth with reduced pod setting and development.

Soil Types on green gram farming

Green gram perform well on a wide range of soils, including red laterite soils, black cotton soils and sandy soils. However, a well-drained loamy to sandy loam soils is the best for its cultivation. Root growth gets restricted on heavy clay soils leading to poor yields. The crop does not tolerate saline soils and show severe iron chlorosis and other micronutrient deficiencies when grown on more alkaline soils.

Best Soil pH for green gram farming

The best pH range is between 6.0 and 7.0. If it is below 6.3, lime should be added to raise pH to the desired level. For best results, lime should be applied and thoroughly incorporated in soil one year prior to growing green gram.

Temperature requirements on green gram farming

Green gram is heat and drought tolerant and therefore can be grown in semi-arid environments. It is also responsive to day length. Short days result in early flowering, while long days result in delayed flowering. Different varieties vary in their photoperiod response. A warm humid climate with temperature ranging from 25- 35^oC is ideal for green gram production.

Green gram varieties in Kenya

The traditional green gram varieties/landraces under cultivation in Kenya are inferior. They are late maturing, require a long harvesting period, low yielding, prone to shattering, are small seeded and susceptible to several diseases. A number of improved varieties have been released in Kenya.

• The local green gram variety – Has small seeds. – Plants mature at different times. – Matures late. – Has a lot of stony seeds, which makes green gram meal difficult to eat.
• N22 thrives best in well-drained sandy loamy soils, golden yellow seeds, semi-determinate
• Plant, tolerant to aphids, yellow mosaic and to powdery mildew, Matures in 80-90 days
• N26 (Nylon)-has determinate growth, pods turn black when mature and contain shiny green grains, Matures in 60 to 65 days
• KS20 – Pods turn brown when dry, grains are dull green in color, grains are bigger in size compared to N26, matures in 80-90 days

Seed treatment against diseases and pests

For the prevention of soil and seed borne diseases and better yield, seeds should be treated with fungicides and insecticides. Additionally, it is important to regularly change the seed source.

Germination test

While the germination percentage of seeds is marked on every packet of seeds, farmers often encounter non-germination of seeds after planting. It is advisable to conduct a germination test before planting whole fields or farms. This is done by taking a few seeds of the green gram (e.g. a table spoonful) and soaking them in water overnight.

The soaked seeds are then wrapped in polythene bag. On the third day, the seeds are examined to assess the number of sprouted seeds. Based on the number of seeds that sprout, the farmer will make a decision on whether to use the seeds or source for alternative seed.

A germination rate of 70-80% is an indication of high seed viability. This test also informs the farmer on whether to place excess seeds in the planting holes or not. If one batch of seed has 60% germination and another 90% germination, the farmer would need to plant more seeds per area from the former batch than the latter. Seeds with good germination capacity and uniformity in size will have good vigour. Seeds with good vigour will produce good quality seedlings that will grow and give good yields.

Site selection

In order to realize good yields, precautions should be taken in selecting the planting location. Farmers should avoid steep sloping land, swampy fields, heavy clays and fields with a lot of couch grass. It is important to look for sites with high soil fertility and also fields where green gram have been grown for no more than two seasons. Crop rotation should be practical where possible.

Land Preparation

A well-prepared seedbed is required for proper germination and establishment of the crop. Land should be ploughed during the dry spell to allow for aeration and to expose soil borne pests to die. Land should also be prepared early enough for planting to coincide with the rains. To obtain a fine seedbed free of big soil clods and weeds, 2–3 ploughings followed by harrowing are needed. Ploughing and harrowing can be carried out using tractor mounted ploughs animal mounted mould board ploughs (oxen) or by hand held hoes

Green gram planting, spacing and seed rate

Seeds for planting should be of high quality, healthy, undamaged and free from insect pests and fungi. Improved varieties should be obtained from an authorized source since poor quality seed will result in a poor crop and yield. For local varieties a source with good quality seed should be sought. Before sowing, shrunken, shriveled, fungal infested and diseased infected seeds must be removed and only good seeds sown.

Seeds should be planted 3-5 cm deep in a well-drained seedbed with fine tilth to avoid staggered germination. If the surface layers are dry, this depth can be increased to 7.5 cm but only if the soils do not crust easily because crusts reduce stand counts. When using oxen plough for planting, the seed should be placed at the side of the furrow.

Green gram spacing

Green gram can be planted alone or intercropped with other crops like maize. When planted alone on a flat bed or ridges, the spacing should be at 45 cm between rows and 15 cm within rows (plant to plants spacing as shown in Figure 1. When inter cropping, the green gram rows are planted in the middle of the accompanying crop and the intra row spacing is maintained at 15 cm. Three seeds should be sown per hole and later thinned to two at first weeding.

Green gram seed rate per acre

The seed rate varies with seed size and season. A seed rate of 22-26 kg/ha or 8- 15 kg/acre or 4-8 ‘gorogoro’ per acre is appropriate. However, it is recommended to calculate the seed rate every season/year since it varies greatly depending on the variety, germination and sowing conditions. The box below gives an example of how to compute seed rate.

Weeding

Weed control in green gram is essential to reduce competition between the crop and the weed, especially at an early growth stage. Weeds can cause up to 50% grain yield loss if not controlled, especially at an early stage. The magnitude of grain loss varies with the intensity and type of weeds present in the field/location. One or two weedings at 25 and 40 days after planting/germination are beneficial to keep the weeds under control. Late emerging weeds will have a smaller effect on yield than would early emerging weeds.

Weed-free crop of green gram harbours lower major insect pest populations, while weedy crop is conducive for pest population buildup. Common weeds that pose problem to green gram include couch grass, star grass, amaranths, wandering Jew (Commelina benghalensis) among others. The most common weeding method is hand weeding but in some areas, farmers use oxen to remove the very early weeds.

Weeds can also be controlled using herbicides (pre-emergence herbicides). A non-selective contact pre-emergence herbicide e.g Roundup (Glyphosate) can be applied to kill all weeds before the land is ploughed. Fifteen days before sowing, the field needs to be pre irrigated with sufficient water to germinate most of the weeds. When weed germinate, Roundup is applied. In order to control later emerging weeds, manual weeding is done 30 days after sowing.

Green gram crop protection

Importance of Pest and Disease Identification

Under different conditions, losses of 10-45% have been reported in green gram due to common blight while 80% has been reported due to angular leaf spot disease. Farmers lave limited access to technical skills and knowledge on how to control most pests and diseases in green gram thereby increasing insurgence.

There is need to innovatively find simpler ways to assist farmers and key stakeholders to correctly identify and manage pests and diseases that affect green gram production. This can be done by continually developing and providing information training manuals and extension materials to crucial stakeholders involved in green gram production. This manual envisages that the trained extension staff will in turn train farmers, share expertise and expedite the adoption of new pest and disease management techniques.

Management of Pest and Diseases using Integrated Pest and Disease Management (IPDM)

Integrated pest management (IPM) is the use of a combination of various strategies for the control of pests and diseases. These practices include the use of plant resistance, physical, cultural, biological, chemical and quarantine (exclusion of diseases from non affected areas) options to maintain pest populations below economic injury levels, with minimal impacts on non-target organisms, food safety, terrestrial and aquatic environments.

In IPM it is important to conduct scouting, monitoring of pests and establishment of action thresholds to guide application of management strategies. Current projections point to low usage of IPM in Kenya by smallholders in many regions thereby making it necessary to promote its use to limit over use of pesticides and enhance food and environmental safety.

Scouting for Pests, Diseases and Weeds

The purpose of scouting is to gain an understanding of insects, diseases, weeds and beneficial insect activity in the green gram crop. Effective monitoring includes assessing their numbers and incidences in the field. Scouting is a critical component of implementing an IPM programme. When scouting, get in the farm and take a close look. If you have a large block of a green gram crop, walk in a Z, V, W or zigzag pattern through the field.

Look at 50 leaves in a field but in small patches you may look at every plant. Make sure you turn the leaves over. The protected, damp areas under plants are often insect and disease’s favourite homes. Check in all wet areas or other troubled spots for symptoms as well as the pests and diseases. Scout the green gram crop once a week in order to identify problems before they get out of control. Once you find insects, diseases or weeds, control them as advised.

Harvesting

During harvesting, proper care should be taken to minimize quantitative and qualitative losses. The harvested green gram should be kept separately from one variety to another to ensure true to type variety (grains).

Harvesting should be done at the right time that is at maturity and when 95 % of the pods have turned black and dry. At this stage, the pods are thin, brittle and prone to shattering during harvest hence a problem during harvesting. Harvesting before the maturity of crop, usually results in lower yields, higher proportion of immature seeds, poor grain quality and more chances of infestation during storage. Delay in harvest would lead to shattering of pods and infection by diseases, pests and other losses caused by birds and rodents.

Avoid harvesting during adverse weather conditions such as rains and overcast weather

Green gram yields per acre

In most counties, green grams are mainly grown for commercial purposes. Very little is retained for household consumption and planting for the next season. The large scale green grams farmers in Kenya tend to do mono-cropping while most small scale farmers do inter-cropping of the green grams with other crops like maize, sorghum and beans.

In Kirinyaga County, all the farmers reports indicate that they do inter-cropping of green grams with maize. The average yield of green grams per acre ranges from 5-7 bags with mono-cropping and 2-4 bags per acre with intercropping.

Where to get green gram seeds in Kenya

The source of green grams seeds in most counties is Kenya Agricultural and Livestock Research Organization (KALRO). Farmers access these seeds from the distribution by the County Government as well as privately from Agro-dealers.

Some counties such as Makueni receive seed distribution from NGOs and other partners. Farmers mostly recycle the previous season’s harvest as seeds, this affects the green gram yield per acre.

Market Price of Green Grams In Kenya

Prices are normally negotiated at the farm level but when farmers take their produce to the market, they sell at the prevailing market prices. Selling price per kilogram of the produce depends on seasons, during harvesting; prices are low while off season, the prices are high.

Selling price of green gram immediately after harvest varies from one county to another. However, the overall selling price at harvest is Kshs. 61 per Kg while the 90Kg bag sells at Kshs. 5,500 on average.

Article Credit: Kalro