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Soil fertility

The CASCAPE project emphasizes the importance of soil fertility to increase agricultural production. We regard soil fertility as one of the most important enabling soil conditions for agricultural production and consider the low and decreasing soil organic matter contents in many CASCAPE sites as a serious threat to current and future agricultural production. During the 2011 growing season fertilizer experiments were performed in all CASCAPE research sites and showed that about half of the variations in yields levels were governed by nutrient availability.

During interviews farmers confirmed that they experience fertilizers as expensive, hard to acquire and difficult to handle, notably:

  • About 35% of the farm related expenditures were on fertilizers and thereby fertilizers are an important cost item for farmers. Yet the application rates are very low and yields are often not much higher than the control experiments (i.e. fields without application of fertilizers). These findings are probably the result of many factors, including low and/or late application, inappropriate crop and nutrient management, etc.
  • The only fertilizers currently available in Ethiopia are urea and DAP, which are relatively cheap and fast-release fertilizers but not suitable for every soil type. Especially on acid soils these fertilizers can be counterproductive.
  • Fertilizer application is not as simple as it sounds. Most of the farmers CASCAPE is working with have only a few years of lower education and require support with regard to appropriate nutrient management.

In order to address the issues listed above, CASCAPE targets soil fertility in different ways:

  1. Performing demonstration trials and organize field events together with farmers, DAs, BoA, Regional Agricultural Research Institutes, etc. In 2012 in more than 12 field days were organized and visited by more than 1000 farmers.
  2. Providing trainings on soil fertility and nutrient management to university staff, DAs and farmers so as to address all stakeholders in the knowledge chain.
  3. Providing guidelines on good nutrient and organic matter management. In CASCAPE we tend to stress that it is much more important to apply proper ratios of nutrients instead of total amounts. In a case study performed in Tigray we found that farmers applied on average 40 kg N/ha as mineral and organic fertilizers. Without extra costs, but with better balancing different nutrients, yields could be improved with about 15%.
  4. CASCAPE is actively involved in the policy debate and the governmental ambition to reformulate the official fertilizer recommendation which are now set at 100 kg DAP + 100 urea per hectare irrespective of crop and soil type. To support the development of improved fertilizer recommendations CASCAPE is engaged in the national soil fertility mapping. In November 2012 a high level expert meeting was organized together with MoA in which an activity agenda for improved fertilizer recommendations was prepared and approved.
  5. As CASCAPE team we have adopted the QUEFTS toolbox as appropriate tool to develop appropriate fertilizer recommendations for N, P and K. The QUEFTS toolbox was developed by Janssen et al. (1990) and its major benefit is that it takes into account interactions between N, P and K. Thereby a balanced fertilizer recommendation is secured. In 2012 the QUEFTS tool was parameterized for teff, wheat and barley and in 2013 parameterization will continue for other crops.
  6. Stressing the importance of soil organic matter management. Demonstration trials confirmed that combinations of organic manure and mineral fertilizers give higher yields and are likely to maintain and/or restore soil health.

Picture: The CASCAPE project organizes many
farmer field days to demonstrate, amongst
others, the benefits of balanced fertilizer application.

 

 

 

 


Table above: Without targeted interventions on nutrient management and fertilizer application yields will remain low, in this example around 2 tons of wheat per hectare. With improved practices yields can drastically improve (results CASCAPE experiments).

Table above: Current levels of soil organic carbon (0-20 cm) in three CASCAPE sites. The results of the other sites are in process.

 

 

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