SOIL FERTILITY AS A BANE OF CROP PRODUCTION IN NIGERIA
By AbdulAzeez Faisal Ishaq
Crops need nutrients just like people do. A well fertile soil should contain all the major nutrients for basic plant nutrition (e.g., nitrogen, phosphorus, and potassium), as well as other nutrients needed in smaller quantities (e.g., calcium, magnesium, sulfur, iron, zinc, copper, boron, molybdenum, nickel). The term soil fertility is the intrinsic ability or capability of the soil to provide plant nutrients and water in adequate amount and when required, for good growth and development of the crops (Agboola, 1986).
Soil that is rich in these nutrients is fertile. Soil provides the support or foundation for plants and most of the nutrients and to have a successful crop production the fertility of the soil should be optimum. Fertility of the soil determines the productivity of the crop, a fertile soil will produce more crops unlike an infertile soil like the ones found in Nigeria. According to FAO (2001), Nigeria is one of the countries with high declining soil fertility. The country was estimated to be losing an average of 24 kg nutrients/ha per year (10kg N; 4kg P2O5, 10kg K2O) in 1990 and 48 kg nutrients/ha per year in 2000, that is, a loss equivalent to 100kg fertilizers/ha per year.
As a result of the low fertility of most soils found in Nigeria, the crop production is low and this increases the rate of importation of agricultural goods. According to the Minister of Transportation, Mr. Rotimi Amaechi ‘Nigeria spends a total of $2 billion annually to import agricultural products into the country’
’ “Poor soil fertility is the fundamental cause for low agricultural production in hunger-endemic areas,” notes Alfred Hartemink of World Soil Information (ISRIC) in Wageningen, the Netherlands.
Apart from the low production of crop, the quality of the crops produced is generally perceived to be low standard, because the crops while growing did not receive enough nutrients that will enhance their quality and most of the crops are prone to attack by pest and diseases. Just as in the case of humans, nutrients are needed to boost the defense system against foreign organisms like virus, it is also similar to the plants, when the plants are not getting enough nutrients, they can be easily attacked by pest and disease leading to possible total crop failure or poor quality of fruit/seeds.
Causes of soil infertility
- Soil mismanagement is one of the major causes of soil infertility, the management of soil is poor especially among the rural farmers due to lack of knowledge. Examples of such mismanagement include
- Inappropriate agricultural practices such as lack of crop rotation, adoption of maximum tillage, inadequate or total lack of fallowing, inadequate fertilization, overgrazing, and absence of mulching the destruction of watersheds, and the opening up of riverbanks and other critical areas have led to silting of riverbeds and loss of watercourses. In addition, uncontrolled use of agro-chemicals and the concomitant problems of chemical persistence in the soil in humid areas and soil-crust formation in arid climates have contributed to Stalinization and destruction of vast agricultural lands. (Ojuola)
- Deforestation and bush burning: Uncontrolled cutting and tree felling without restocking and rampant bush burning are the order of the day. These increases the leaching of nutrients down the soil
(Bush burning on the left and deforestation on the right) photo credit: Eduresource
- Soil erosion: Erosion is the washing away of the topsoil by wind, water or air. Nutrients that are found in the topsoil which are readily available for plants uptake are being washed away during erosion thus leaving the soil with little or no nutrients to supple to the plants. Erosion is a serious problem in Nigeria especially the south-eastern part of the country.
How to improve soil fertility in Nigeria
The secret behind most fertile lands is a good soil management practice, Soil management is the application of operations, practices and treatments to protect soil and enhance its performance such as soil fertility or soil mechanics (Wikipedia). The advantages of soil management are numerous, they include maintaining of soil fertility, reducing of soil erosion, helps in increasing yield, restoring of soil fertility e.t.c. With good soil management practice the fertility of most of our soils can be restored and will help to increase the quality of crops produced. Soil management practice includes
Crop rotation, bush fallowing, minimum tillage, mulching, afforestation e.t.c.
- FAO (2001). Soil Fertility Management in Support of Food security in Sub-Saharan Africa.
- Ojuola, Status of soil management in Nigeria, pg 14-15