Soil salinity and food security in Nigeria

Over the years, bad agronomic practices have been identified among the key factors driving food insecurity in Nigeria.

Among the consequences of bad agronomic practices is induced soil salinity. Increasing Soil Salinity is becoming an alarming situation in Nigeria, mostly predominant in the northern part of the country where irrigation is mostly used in cultivating field crops. Despite this impediment, the northern region still contributes a higher percentage towards attaining food security in Nigeria.

However, unattended to the increasing soil salinization coupled with the lingering insecurity in this region would be a great setback in attaining food security in Nigeria in the nearest future.

To ensure food security in Nigeria, we need to work toward the global call “best practices in transforming food systems for affordable healthy diets and addressing key drivers of food security and malnutrition ”

We believe that with the best practice approach, proper dissemination of quality information, and introduction of innovation to farmers & urban gardeners we will be able to ensure food security in the years to come.

• Soil salinity is the key limiting factor to food security
• Soil salinity simply means the salt content in the soil, in a broad sense, it can be referred to as the measure of minerals and salts within the soil that can be dissolved in water furthermore the ions responsible for soil salinity re: Na+, K+, Ca2+, Mg2+, and Cl−

Of what importance is this awareness to our farmers?
Our farmers may not be able to reclaim saline soil but we must understand ad agronomic practice we engage daily on the farm that contributes to the causes of soil salinity, also it is paramount our farmers can identify the signs of a field land tending toward salinity to reduce the increasing input of inorganic fertilizer as a result of the f sudden experience of decline in yield in our farm irrespective of the field size.

Some bad agronomic practices contributing to soil salinity are:

• Negligence in conducting a soil test
• Poor source of irrigation water and high frequency of irrigation
• Poor drainage system and bad irrigation system management
• Excessive inorganic fertilizer quantification and bad methods of application

Negligence of conducting soil tests

Most of our farmers concentrate more on supplying their crops with the essential elements (Nitrogen, Phosphorus, and Potassium) using inorganic fertilizers but fail to identify other factors that could limit plant performance such as salinity which occurs due to the presence of excess salts (e.g., NaCl) in the soil.

Poor source of irrigation water and frequency of irrigation:
The use of salt-laden sources of water for irrigation can result in soil salinity. To worsen this situation, some farmers arbitrarily increase the frequency of irrigation, once they notice the poor performance of crops, beyond crops requirement. Summarily, frequent irrigation does increase soil salinity if irrigation water sources are not salt-free.

Poor drainage system
Most farmers concentrate more on providing irrigation to their field crops but only a few farmers also provide drainage outlets for excess water. Most of our farmers leave this excess water on the field, therefore, this excess water evaporates and salt precipitants are left behind if the irrigation water is laden with salt.

Excessive inorganic fertilizer quantification and bad method of application

Most farmers assume that the higher the fertilizer, the higher the yield, irrespective of the actual causes of poor performance of plants in the field. They would keep on increasing the quantity of fertilizer which further results in excess on the field and may thereby lead to soil salinity in the coming years. Also, the method of fertilizer application, if not done as recommended by the manufacturer’s guide, can contribute to increased soil salinity.

“Soil Salinity is a threat to photosynthesis and respiration processes, if not properly addressed, Humans and Plants will be trending toward extinction in the years to come” Nafesat Lawal

Soil Salinity and Photosynthesis
Soil salinity prevents water uptake by plants thereby exposing plants to drought stress. To conserve water, plants close their leaves’ stomata to prevent water loss through transpiration. However, this process also simultaneously restricts the entry of CO2 through the leaves into the plant thereby reducing the rate of photosynthesis by plants.

Reclaiming Salt-affected Soils in Agriculture to Reduce Land Degradation
According to the UNU Institute for Water, Environment, and Health (UNU-INWEH) on the Economics of Salt-induced Land Degradation and Restoration, it has been gathered that an average of 2,000 hectares of irrigated land in arid and semi-arid areas across 75 countries in the world have been degraded by salt over the past 20 years.

During a phone consultation with Professor Ayodele Josua Odofin of the Department of Soil Science and Land Management (FUT MINNA), he gave the following advice on managing salt-affected soils.

He advised that to reclaim salt-induced land degradation, the following points should be put into adequate consideration. The method used for reclaiming salt-affected Soils differs depending on the type of salinity in question.

Soil Testing: Soil analysis is the first approach to determine the type of salinity (Saline Soil, Sodic Soil, and Saline Sodic Soil) being experienced by farmers. Soil tests should be conducted to gather information such as Soil pH, Soil Electrical Conductivity (EC), cation exchange capacity (CEC), sodium adsorption ratio (SAR), and Sodium Percentage.
Some basic agronomic practices in reclaiming saline soil
1. Farmers are advised to cultivate salt tolerant varieties on affected soils
2. Provide quality irrigation water source and good drainage outlets
3. Increase organic manure incorporation into the soil
4. Avoid excess inorganic fertilizer quantification and improper method of application.