Feedback: Treat soil before next tomato season

Wednesday March 18 2020

An agriculture extension official inspects tomatoes in a farm. Before planting any crops, ensure that you treat your farm's soil. FILE PHOTO | NMG



I am a tomato farmer in Meru and would like advice on soil treatment for the second season.

Julie Mukami, Nairobi

There are many methods of soil treatment and they include solarisation, heat treatment and fumigation. Solarisation involves thermal disinfecting of soil by trapping solar radiation under plastic mulch and is done to eliminate soil-borne pests.

It involves covering the soil with clear plastic to transmit heat as deep as possible into the soil. It is carried out for a period of 3-8 weeks.

It can be combined with fungicides, biological and cultural practices to make it more effective. Combination of solarisation and dazomet or calcium cyanamid results in good control of root-knot nematodes in tomatoes.

Polythene sheets are easily available. On the other hand, heat treatment is the use of heat on the soil to get rid of pests.

Dry heat involves the use of combustion or electrical resistance in form of a flame or current respectively. Moist heat involves treatment of the media with hot water or steam.

However, this requires a lot of labour to apply the hot water. Lastly, fumigation is the use of fumigants to treat the soil.

Fumigants are volatile and are applied through the pores of the soil. They act as toxicants to soil-borne pathogens and other harmful organisms.

The most commonly used fumigants are chloropicrin (tear gas), which is a liquid applied into soil that is already covered with plastic sheet.

The treatment is carried out for 1-3 days under cover and for a period of two weeks or until the gas odour cannot be sensed. 1, 3-Dichloropropene is another fumigant which is effective in the control of nematodes, insects and also suppresses some weeds.

Carol Mutua,
Department of Crops, Horticulture and Soils, Egerton University.



I am Martin and I want to grow pumpkins on a large-scale. I wanted to know the availability of market locally.

The market for pumpkins is there in groceries, supermarkets, open air markets, urban areas, hotels and in flour milling companies for making porridge flour for children and adults.

The market for pumpkin is not limited, therefore, you cannot lack market for your produce and the profits are good.

Carol Mutua,
Department of Crops, Horticulture and Soils, Egerton University.



Please, can you help me find market for poultry products if I engage in the business?

Omwami Ashiali, Nanyuki

With the increasing demand for white meat, poultry farming is a good venture. Have cocks for sale during the festive season and form groups to strengthen your bargaining power on farm inputs and market prices.

Consult Marura Environment Conservation Group, which is engaged in poultry farming in Nanyuki.
Dennis Kigiri,
Department of Animal Science, Egerton University.


I am a small-scale farmer and I started poultry farming, keeping the Kienyej birds. The problem is the market of the eggs around Nyahururu is small. I also want to keep fish.
Bernard Macua

It is always recommended to start a business small and grow. For small-scale Kienyeji poultry farming, forming a group with farmers doing the same business is advisable.

It is also prudent to reach out to markets outside Nyahururu. Fish farming is encouraged to achieve food security in Kenya, especially protein nutrition. Kindly talk to Ben, an aquaculture scientist at Egerton University on 0725231196.

Dennis Kigiri,
Department of Animal Science, Egerton University.


I want to do soil sampling and later test. Kindly help me.
Tein Mulla, Narok

Select areas within the farm that can give a good picture of each field of the land. Avoid areas such as where soil has been washed away, flooded soils, areas next to the house, old manure or crop residue heaps, animal droppings and plots where fertiliser has been applied in recent days.

Collect soil from at least five points per field in a zig-zag manner. For one acre, take soil from about 20 points. Use a clean jembe or spade to collect the soil into a clean plastic bucket.

Remove any soil sticking on the jembe using a clean panga or knife. Do not use a stick to remove soil from the jembe to avoid adding plant materials into the soil.

Mix the soil well and take a small sample of about one cup for soil analysis. If the soil is too wet to mix well, place it on a clean plain paper to dry in the sun for a few days.

Once dry, break the big particles and mix well. Put the sample in a bag and label it with the name of the farm, the previous crop and date of sampling.

Place the label on top of the sample bag and not in the soil. Take the sample to reputable laboratories like those of Kalro for testing.

Hezekiah Korir, Crops,
Horticulture and Soils Deparment, Egerton University.



Is there a way to remedy soil that is classified as shallow and clayey?
Salem Gzan

The shallow soil restricts root elongation and spreading. Due to shallowness, less volume of soil is available to store nutrients.

Manage it by growing shallow-rooted crops, frequent renewal of soil fertility and adding fertilisers and manures and growing crops that can withstand shallowness like mangoes and goose berry.

For clayey soils, when moist, the soils should be dug with a spading fork rather than with a shovel or spade. As the soil is turned over, the large clods should be broken up with the side of the fork.

The clods that remain should be exposed to the sun and air. Animal manures, green plant material, compost, and leaf mould are especially good for improving this soil condition.

Hezekiah Korir, Crops,
Horticulture and soils Department, Egerton University



Is tap water good for irrigating vegetables?

Jacks Queens, Kisumu

The source of the tap water will determine whether it is good or bad. To know if tap water is good, you need to measure the total soluble salts.

The water may contain a lot of salts which are not good for vegetable production as this may lead to loss of water by the plants causing wilting.

Additionally, tap water may be treated with too much chlorine and this may affect crop growth.

Carol Mutua,
Department of Crops, Horticulture and Soils, Egerton University