Unfortunately, many farmers do not replace lost nutrients after harvesting their crops.
When farmers harvest crops, they have to replenish the lost nutrients through application of fertilisers, which has not been embraced by most Ugandans.
If farmers do not replace the nutrients in the soil after harvest, production goes down. It is like having a shop that one sets up but is reluctant to restock.
How to deal with farmers’ reluctance
For farmers to know which nutrients are lacking in their soils, they should contact experts at National Agricultural Research Organisation (NARO) centres, including consulting extension workers near them for information on how best they can understand their soils.
There are only two major centres with such services that is National Agriculture Research Laboratories (Kawanda) and Makerere University (Kabanyoro).
How is soil analysis done?
The five soil samples are put in a basin and mixed thoroughly before 1kg of soil is put in a clean container. This is taken for analysis in a laboratory.
Soil sampling and analysis starts with experts visiting the garden. Samples to a depth of 0-15cm are taken from all parts of the garden.
The areas from which the samples are taken should not have any trace of organic manure such as cow dung, chicken droppings or any other fertiliser as these could compromise the final results.
Experts look out for the pH, which is the acidity and alkalinity of the soil, organic matter, NPK, sodium, calcium and the proportion of sand clay and silt in addition to physical properties.
To maintain soil fertility farmers should apply both organic and inorganic fertilisers. Organic fertilisers can be got from cow dung, chicken and goat droppings.
For appropriate nutrient use follow the 4R nutrient stewardship.
- Right source of nutrients
- Right rate
- Right time and stage of plant growth
- Right method.
Fertiliser applications should be done at the beginning of the rainy seasons. Fertilisers are applied in the pits.
It is not cost effective to irrigate without applying fertilisers. It is also not recommended to fertilise in acid, compacted or dry soils because the fertilisers will not be effective.
Use soluble fertilisers (nitrogen and potassium) in split doses, for example, 10grammes per plant per dose across three weeks.
Intensification necessary when fertilisers are used (more plants per unit area). For example, if one is using fertilisers in bananas, they can increase the number of pits from 450 to 600 per acre.
Maize can take 30kg per acre instead of the normal 20kg because the crops have got additional food to feed on.
Farmers’ training needed in use of fertilisers and soil sampling for analyses.