Acidic soils deal blow to food security efforts

Soil analysis. Kenya's soil fertility is deteriorating. PHOTO | FILE | NATION MEDIA GROUP

What you need to know:

  • Continuous use of DAP has been blamed for pumping phosphorous into the soil while ignoring other elements such as potassium and zinc.
  • To rectify the situation, scientists called for massive liming to neutralise the acidity and create better conditions for crops to grow.

Most of Kenya’s soils are sick and cannot sustain any meaningful agriculture, a new study has found.

A study commissioned by the Nation Media Group and which covered 11 counties, paints a sorry picture of the status of our soil, with the situation worsened by inaction from both levels of government.

This means that millions of farmers — most of whom have no other source of livelihood — till their land in vain.

The investigation, which covered Trans Nzoia, Bungoma, Uasin Gishu, Bomet, Nyamira, Narok, Kisii, Makueni, Kirinyaga and Nyeri — some of Kenya’s most important food baskets — found the soils too acidic, a condition that blocks nutrients from getting into the crops.

And while fertiliser has often been used to enrich the soil, Kenya’s farmers have little respite as most of the inputs only serve to increase acidity.


The report, which comes five years after President Uhuru Kenyatta launched a national survey and called for urgent rehabilitation of soils, is a damning indictment of the national and county governments.

Scientists in the project carried out in 2014 had proposed a number of remedies, including switching from Diammonium Phosphate (DAP) fertiliser to Nitrogen Phosphorous Potassium (NPK) and embarking on a national liming programme to reduce acidity.

Continuous use of DAP has been blamed for pumping phosphorous into the soil while ignoring other elements such as potassium and zinc.

However, five years down the line, little has been done even as production dips, posing a major food security challenge for the growing population and hurting an economy that depends largely on agriculture.

The Nation team that visited farms in the 11 counties came face to face with a sorry sight, with some of the mature maize crops reaching knee height instead of the regular height of at least two metres, for the hybrid variety, projecting little harvest from those regions.


The report comes on the back of an admission by the Government two weeks ago that farmers will this year harvest only 33 million bags of maize, compared with 44 million last year.

The 25 per cent drop also falls far short of the 52 million bags the government had targeted for this year’s harvest expected from next month.

Kenyan farmers reap a third of what their counterparts in China get and a fifth of the average yield in the US.

This variation has largely been attributed to the condition of the soil, with experts estimating that Kenyan farmers lose up to Sh30 billion annually due to depleted soils.

The 2014 analysis of soils in Kenya showed that the acidity levels in most farms were way higher than the recommended level because of continuous use of inorganic fertiliser, in particular DAP.


The survey by the Kenya Agricultural and Livestock Research Organisation (Kalro), which was carried out in 164 locations, recommended the types of fertilisers to be used in each sub-county, depending on the soil status.

But there was no follow-up to ensure implementation. Instead, the government, through its fertiliser subsidy, indiscriminately dispenses DAP without any regard to a farmer’s soil condition.

To rectify the situation, scientists called for massive liming to neutralise the acidity and create better conditions for crops to grow.

But many farmers cannot afford it. A tonne of lime goes for Sh4,000, way beyond the reach of small-scale holders, who form the bulk of Kenyan farmers.

Lime is also cumbersome, requiring several tonnes over the years for its effects to be seen.

Farmers who spoke to the Nation said they would be willing to lime their farms if they got support from the government. “We have been told that lime can help us to increase our yields, but our pockets do not permit,” said Mr John Bosire, a farmer in Nyamira, whose soil was found to be highly acidic.

The problem of deteriorating soil fertility has been compounded by the fact that most farmers do not know the status of their soil.


A test of soil sample at the national laboratory goes for Sh1,500 and a farmer requires three sample tests from different points of the farm.

“The government does a very good job with policy and research. The private sector needs to do its part,” says Mr Dan Okumu, country manager of OCP, a fertiliser company.

The company does free mobile soil testing. He says Kenya’s soils are highly acidic and lack important micronutrients such as sulphur. “Farmers would be better reached if they formed or joined co-operatives,” he says.

Kalro director Patrick Gacheru says if farmers have their soils tested, they will know their pH status and the elements that are missing in order to fix them.

Farmers who have conducted tests and limed their soil have seen an increase in their harvests.

One of them is Mr Rodney Kili, who told the Nation that his maize yield shot up from 12 bags an acre to 25 after he limed his soil, raising the pH level from four to five.

The optimum pH level is six. In Nyamira County, a pilot plan between the county and Amiran, an agricultural input firm, saw farmers’ yields improve significantly after they came up with fertiliser that was best-suited for the soils.

“Farmers had their maize production increase between 10 and 15 bags of maize from a low of five bags,” said agriculture executive Peris Mong’are.


She said some areas of Nyamira have recorded pH as low as three, way too acidic for any production to take place.

Agriculture Chief Administrative Secretary Andrew Tuimur denied that the government has left farmers to their own devices, insisting that importing blended fertiliser was now policy.

Dr Tuimur said the Toyota Tsusho fertiliser blending plant in Eldoret has also helped farmers to get the supplement that is specific to their soil, and that growers are now embracing these types as opposed to DAP.

“We are setting up a fertiliser board which will address challenges,” said Dr Tuimur.

The national government will work with counties to see if they can also extend the subsidy programme to cover lime, he said.

The government last year drafted an ambitious programme that would have seen farmers restricted to purchasing fertiliser that suits their soil in a bid to curb deteriorating soil health, but it has been accused of saying all the right things and doing little.

The study revealed that maize-growing counties, which have been using excessive DAP, recorded the poorest state of soil.

Trans Nzoia County, a key maize region, ranged from strongly acidic (4.53) to slightly acidic (7.12).


It recommended the use of alternative fertilisers such as Single Super Phosphate (SSP), Calcium Ammonium Nitrogen (CAN) and Nitrogen Phosphorous Potassium (NPK) and Mavuno.

“We are currently working on a scheme that will see the government issue e-vouchers to farmers in the next planting season to ensure that they get only the fertiliser that suits their soils at their local agro-vets,” said Agriculture Principal Secretary Hamadi Boga.

Under the scheme, farmers will buy e-vouchers from the Agriculture offices in their counties and later redeem them at agro-shops for subsidised fertilisers.

But results from the NPK switch have not been as good, though experts blame the manner of use and not the input itself for non-performance.

The inefficient distribution of government-subsidised fertilisers — which retail at Sh1,800 a bag — has also been blamed for poor maize performance.

This year, farmers missed the State-backed subsidy fertiliser after corruption claims marred procurement.

Unscrupulous officials have been conniving with traders to deny genuine producers the fertiliser, meaning they planted without the supplement, hence compromising production.