Nigeria: Prolonged Use of Fertilisers Hurting Nigerian Soils 7 July 2014 , By Onche Odeh, Source: Independent Fears are rife that the continuous use of inorganic fertilisers may be killing the quality of soils across parts of Nigeria. This is as experts have said soil has been grossly undermined, despite being one of the most overlooked ingredients in farming. A report by the United Nations Food and Agriculture Organisation (FAO) has disclosed that 25 per cent of the planets land is highly degraded and that only 10 per cent is improving. This is already visible in Ebonyi State, South East Nigeria, where a research by head, Department of Soil and Environmental Management, Faculty of Agriculture and Natural Resources Management, Ebonyi State University, Professor Emmanuel Ogbodo, has revealed fears that long-term application of inorganic fertilisers to the soils in the state Agro-ecology may be contributing to its productivity constraints. Ogbodo, who confirmed the findings in a phone interview with Sunday Independent said the study was conducted in the major crop production communities, representing the major soils of the state, to assess the impact of long term use of inorganic fertilizers on the soils. Soil samples were collected from fifteen different farm locations that have the records of continuous application of inorganic fertilisers and analysed for their physical characteristics, chemical properties, and microbial population. The results of the analysis indicated that the soils were very strongly, whereas exchangeable acidity (EA) was very high across the entire locations. Although Ogbodo highlighted that the application of lime and complementary use of organic manure and mineral fertilisers could restore the soil to sound fertility, he observed that almost all the land which can be cropped are already in use, and that large scale crop production in the area depends on use of inorganic fertilisers. Scientific investigations have revealed that low fertility of the soils is the primary constraint to increased crop yields. Researchers have proffered reasons for such situations elsewhere, which pointed primarily to inorganic fertiliser use, he noted. With current levels of inorganic fertiliser use in the area, at about 400 kilogrammes per hectare, he said the potential for fertilisers to have negative impacts on productivity and environmental quality is great, in which case he said it can lead to productivity declines and environmental problems. It is therefore essential that agencies promoting increased fertiliser use be aware of the potential for negative impacts since the use has become widespread, so that appropriate agricultural management strategies, monitoring systems, and policies can be put in place to limit the negative impacts, Ogbodo stated. Ogbodos study was conducted in 15 farm locations, which he said were intentionally chosen based on the records from the state Agricultural Development Programme (ADP), to represent the major soils in the state. He said: The study was conducted in 2012, covering the major farming communities in Ebonyi State, and which soils are representative of the major soils of Ebonyi State. After analysis, he said the, The chemical characteristics show the soils to be very strongly Acidic to strongly acidic (4.0-5.6) almost across the entire locations. Organic carbon ranged from low to high (0.51-1.84) across the locations; exchangeable acidity was very high over the entire locations. The fertility inference is that the soils suffer multiple nutrient deficiencies, despite the fact that they have records of receiving inorganic nutrients (chemical) annually as an essential component of the farming system, and which the aim is to maintain good yield in the absence of sufficient organic, natural manure, Ogbodo disclosed. The research and reports from FAO shows that the use of mineral fertilisers alone has not been helpful in agricultural production as it has been associated with soil acidity and nutrient imbalances. According to the soil expert, acidification and depletion of soil nutrients is a product of not only the application of inorganic fertilisers, but of the farmers agricultural practices in general. When crops, and in all cases residues, are removed, as is always the practice in this area, it creates deficit in soil organic matter and a parallel decrease in levels of base nutrients and, therefore, acidification, he said, noting, however, that this process is slower in comparison to acidification by fertilisers, which can be rapid with the potential of decimating crop yields in a short period of time.
Posted on: Tue, 08 Jul 2014 12:55:30 +0000
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