Planting season is here, have you tested your soil yet?

Sunday March 4 2018

As farmers get into the planting season, using

As farmers get into the planting season, using good seed is of paramount importance. PHOTO BY LOMINDA AFEDRARU 

By Christine Katende

Except for a few feed manufacturers who keep to the standards in poultry feed formulations, many feed companies in the country make very poor quality feeds, a situation which has led to huge losses.
Following the release of Uganda’s seasonal climate outlook for March to May this year by Uganda National Meteorological Authority, several farmers are already planting, while others are busy preparing their land, but the big question is, do you know the nutritional value of your soil?
Put it in other words, have you done a soil test before you prepare for planting?
Knowledge on soil fertility and soil testing is quite low in Uganda, according to Beatrice Sadina a senior Soil Scientist at NaSARRI.
Out of thousands of farmers in Uganda, about only 10 per cent have their soils tested.
“Most farmers are not aware of their soil fertility status despite the fact that the soils are sick. Crops, like all living things, require nutrients and in the right proportion to be healthy,” says Sadina.
Soil tests, according to Sadina, helps farmers understand their soils, deal with the deficiencies and excesses and ensure that the soil nutritional content is correct.

Haphazard use of fertiliser
But normally when it rains, farmers rush to prepare their land without testing, and later go straight into planting while using a lot of fertiliser, with DAP and CAN being the inputs of choice.
David Kalule, an agricultural consultant focusing on groundnut growing, notes that the trend of planting ‘blindly’ leads to negative outcomes.
“Continuous use of DAP increases some elements in the soil and decreases others. Different plants require different elements and when an element like iron or phosphorous becomes too much, it affects the growth of another crop such as cabbage, maize, carrots or even potatoes and when a farmer uses fertilisers on soils that do not require it, it translates to excessiveness of certain nutrients leading to low yields,” he says.
There are several soil tests, which include testing the soil pH. This checks on the acidity of the soil as the pH is a key factor in plant growth and it affects nutrients availability in plants.
When pH is maintained at the proper level for a given plant, nutrients are available at the maximum.
Most plants prefer a soil pH of between 6.0-7.0 except for tubers such as potatoes, which need a more acidic environment.

Sample soil immediately after harvest
When sampling, a farmer should divide the area to be sampled into different parts, collecting a minimum of 5-10 samples, then combine them and submit for analysis.
One should avoid sampling very wet soils or soils that have been recently fertilised, and samples should be at least six to eight inches from the ground level.
One should avoid areas of high erosion or those close to trees. The best time of the year to sample is immediately after a harvest.
Soil sampling can also be done during the growing season to help in identifying plant growth problems where soils are sampled when symptoms are present to ascertain the problem and take curative action during the current growing season.
The question on how often sampling should be done depends on individual crops where for perennial plants like the trees, testing should be done prior to planting and once every two to three years.
For annuals such as maize or beans, soils should be tested once every two years.
For large-scale farmers who regularly use fertiliser, manure or other soil modifications, testing should be done more frequently to monitor changing soil conditions and prevent the build-up of excess levels of nutrients or salts.

Poor knowledge
Farmers should keep all soil tests records for the areas sampled, fertiliser applied and plant yields as this allows them to relate the plant performance in terms of yield to the soil test results and fertilisation practices. Soil testing technologies are now advanced and closer to the farmer. According to Sadina, there are portable soil testing technologies and laboratories in various places across the country.
However, soil testing has several challenges as some farmers once given the recommendations lack someone to help them interpret the results. “We do train some farmers,” she says.
Some extension officers are also not well versed with the technology and cannot interpret the recommendations such as NPK 17:0:17 or 23:23:0 and cannot even help the farmer blend the recommendations.

Where to test your soil
Soil testing technologies are now advanced and closer to the farmers. According to Sadina, there are portable soil testing technologies and laboratories in various places across the country.
At Makerere University and Namulonge, soil samples are tested for about Shs35,000. Sadina also says a farmer can purchase a soil testing kit at Shs180,000. “We encourage farmers to buy these kits,” she says.