Concerns over soil tests

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One of the principal challenges for Nigeria’s agricultural sector and smallholder farmers is low yields. There are a number of explanations for the differences in yields. A major reason, most cited, is soil fertility and the ability to improve and manage it. Experts recommended soil tests. How are these challenges producing accurate soil tests for farmers, DANIEL ESSIET reports.


Nigeria and the rest of Africa have a long history of agriculture playing a crucial part in economic growth. The sector is seen as critical to sustainable economic growth, increased trade and agro exports. Sadly, according to the Food and Agriculture Organisation (FAO), yields in Nigeria and the rest of sub-Saharan Africa have grown at a slower rate.

Experts give a number of explanations for the differences in yields and yield improvements, ranging from the availability of agricultural training to access to labour-saving technology. But one of the most cited reasons is soil fertility and the ability to improve and manage it.

The International Institute for Tropical Agriculture (IITA) said as a result of the inherent low fertility of African soils and subsequent land degradation, only 16 percent of the land has soil of high quality and about 13 per cent has soil of medium quality.

Corroborating this, a report from the International Centre for Tropical Agriculture (CIAT) noted that many farmers try to coax crops out of sandy soils that are not ideal for holding water and nutrients.

This highlights the crucial role soil and soil testing play.

Experts said soil test would help farmers know whether it would be productive to grow a particular crop in an area, and how to apply fertiliser if the area is lacking enough nutrients.

One of them was the Vice Chancellor, Federal University of Agriculture, Abeokuta, Prof Felix Salako.

Salako is a soil scientist. He has spent his days advising farmers on the best way to manage their farms   for crops to reach yield potential.

Like other geographical impediments, he  explained that soil  was  a dynamic and continually changing eco system that required a holistic approach for a farmer to be able to make more informed decisions on application of nutrients and managing the farm health.

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He  stressed that a deeper understanding of the factors that impact on the soil health  was  key to boosting food production.

Speaking with The Nation, Salako said it was important to take different soil samples throughout the field at varying depths to get a good reading on what nutrients the farm has and what to improve on.

He said a professional conducted soil testing was an excellent method for estimating the fertility status of a soil. This is because it provides valuable information for developing a sound fertility management programme.

He said a lot is required to take a proper soil test, such as not testing on the edge of two zones and not doing it in an area that is prone to compaction or overlap. The other things  are that topography and slope will influence soil analysis, besides water movement.

The  don  said doing it right was isn’t as straightforward as one might think.

Though the process may seem easy, Salako noted that the result may provide misrepresentation if the testing is conducted on marginal, unrepresentative land.

He cautioned against carrying out soil test during rainy season as it might not offer as much insight as in the dry season.

Salako told The Nation there were standard methods to test for nitrogen, phosphorus, potassium and sulfur soils, adding that as long as a lab uses those methods the result will be reliable.

The don explained that variability could exist within a field because of inherent soil formation factors and past production practices. As such, the collection of a representative soil sample could become a challenge.

For accurate interpretations and recommendations, he stressed it was important to follow the sampling instruction from a lab as closely as possible.

While there are legitimate considerations in choosing a lab, he added that the most important consideration is whether the test methods used by the lab  were  appropriate for the conditions where the test will be used.

Without this being done, Salako said there will always be a possibility for flawed soil analysis if that lab was not using methods appropriate to  local conditions, adding that  even the highest-quality lab might provide incorrect results, interpretations and recommendations.

Salako said fake and flawed soil tests were possible,  following the increasing menace of quackery among soil scientists nationwide.

He encouraged agro producers to seek experts at universities and governments to make sure they use proper recommendations, and to examine new technologies from all sides.

The Managing Director, Agrobosco Nigeria, John Bosco, said soils form the structural foundation for intensive arable farming work, making testing very important as failure to test soils adequately and correctly  could result in  financial and safety risks.

A large number of farmers, instead of going for soil testing to determine the quality of their soil, he noted, were indiscriminately using fertiliser and pesticide without analysing land and soil quality.

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Before a farming project commences, Bosco  noted that it was  important to understand the properties of the soil, and to use the information to determine what crops to plant and the nutrients the soil requires.

Globally,  farmers  carry out  soil sampling of their farm  fields  every three years, determine  phosphorus, Nitrogen  and potassium availability. This, according to a   lead agronomist for Flour Milling Association of Nigeria (FMAN), Tijani Abdullahi, does not happen in Nigeria. He has long been an advocate for  soil testing.

Abdullahi said it revealed the behaviour of soils under varying conditions of moisture, loading, stress and  temperature.

Though soil testing was not an absolute science, he noted, however, that it assisted farmers to make  qualified fertility management decisions based on soil nutrient inventory.

He confirmed that  soil test samples sent to different labs  could produce  different recommendations.

One of the most important considerations in soil testing  according to the  Country Manager, OCP Nigeria, Mr Caleb Usoh,  was that it must be correlated and validated with local field data  to be useful for making fertiliser recommendations.

The objective, he added,   is to maximise net returns on fertiliser investments in the year of application.

To ensure appropriate use of fertilisers, he  said  the organisation had launched mobile soil testing labs. Now, farmers can get samples tested at their doorstep.  The mobile labs,according to him,  are equipped with latest gear and  can  used for macro and micro nutrient  soil analysis.

Usoh   said when one summits soil samples for laboratory analysis, there was a guarantee  of reliable results.

Farmers, he  said, were  provided information on nutrient status of their soil along with recommendations on appropriate dosage of nutrients to be applied for improving soil health and its fertility.

Deterioration of soil chemical, physical and biological health,he  maintained, was one of the reasons for stagnation of agricultural productivity in Nigeria.

Usoh said  the groundbreaking of OCP Africa’s $13 million Sokoto Agricultural Centre of Excellence comprising a fertiliser blending plant with a production capacity of 200,000 metric tonnes(MT) per annum and training facilities for farmers, fertiliser blenders and other stake holders in the agricultural value chain has taken place.

He said facilities that would be at the blending plant include a modern fertiliser blending equipment, process building/warehouse, administrative building, trailer park, other ancillary facilities and a One Stop Shop for farmers to access training and all farm inputs.

The Managing Director, Lordsfield  Limited, Oluropo Olajugba, said avoiding flawed soil analysis involved using precision technology that goes far beyond traditional soil sampling to help growers make better soil management decisions.

With precision technology that   delivers high resolution top soil maps that detail in-field variability of soil’s chemical and physical properties, Olajugba said farmers will be able  to give the soil what it needs by applying inputs precisely and accurately.

He explained that what his company was offering was  modern technology that assist in how soils are analysed, by equipping farmers to  improve crop yields and incomes. He reiterated that soil health was a key success factor in agriculture, adding that as fertility levels continue to decrease, more farmers will need more data to understand how to better manage their inputs.

Last year, the Nigeria Institute of Soil Science (NISS) said it was ready to clampdown on unqualified and fake soil scientists in the country. The institute said it had reached an advanced stage towards the planned prosecution of unqualified soil scientists.

The Registrar, NISS, ProfVictor Chude, who made this known in Abuja, at the induction of newly-registered soil scientists, said the move became necessary following high level of quackery among soil scientists in the country. He said the induction of the soil scientists was to establish the culture of standards.

He said the NISS Act 2017 was to regulate the profession of soil science, the use and management of soil resources to maintain high soil quality for sustainable crop production.

According to him, soil scientists play the same role as doctors do, and if the soil is not properly treated, it will not support the production of crops and it will not allow it produce good yield.

“With the induction of the soil scientists, there is going to be awareness created for people to know how we operate. We are going to have an amendment to the Act as soil is a vital and non-renewable component of the ecosystem,” he said.

However, President of NISS and Chairman of the Council, Prof Ayo Ogunkunle, said the negative impact of charlatans among soil scientists could affect millions of people for several years before detection.

Ogunkunle, who noted that the importance of the regulation of standards qualification and skills of soil scientists could not be over-emphasised, said soil resources of the nation must not be neglected or allowed to degrade.

Noting that the detailed survey and mapping of Nigeria’s soil resources are overdue, he  solicited support from the government in view of its importance.

He said: “Agricultural soil is the real wealth of a nation as it is basic to human existence, essential for food, feeds, fibres and fuel production. A crucial requirement for appropriate use and management of the soil resources of a nation is a good knowledge of the various soil components and characteristics. This is not possible without a detailed soil survey of the country,” he said.