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Facts I

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Seedball Technology Fact Sheet

Intro

Seedball as a technology was developed in the frame of the permaculture movement in Japan in order to enable cultivation in areas normally unsuitable for cropping. It was then adapted in Australia for rangeland amelioration, adopted by the „guerillia gardening“ community and is distributed for this purpose by organisations like Greenpeace.

Background

With respect to natural resources the semi-arid Sahelian environment is characterised by high climatic variability in space and time. The growing season is short (approximately 3 months), its beginning unpredictable and early season droughts after sowing common. Cropping risk is further increased by sandy soils with low nutrient status and low water holding capacity. Farmers are mainly subsistence-oriented smallholders with low invest-ment capital. Due to the short cropping season, timely sowing is crucial in order to realize the pearl millet yield potential. Every day of later sowing is decreasing the latter. That is why dry sowing before the season is commonly practiced. However dry sowing has its risks including predation of the seeds e.g. by rodents or birds and crop loss due to early droughts after minimal rains that led to seed germination.

The seedball concept

Seedballs consist of a simple mixture of soil materials that stick together, water, seeds, and additives that improve plant performance. The latter can be nutrients, pesticides or anti-rodent components. In the framework of the SMIL-programme emphasis was on optimisation of nutrient and seed content as well as size. The principle idea was that seedballs should be based on local materials that are affordable for subsistence farmers.

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Hypotheses why seedballs should work in the Sahelian context

1. Application of seedballs lowers the seed need per hectare.
2. They conserve seed under dry sowing conditions against rodents, birds and other pests by physical protection.
3. Seeds do not germinate under too low rainfall.
4. In the soil they attract water due to a higher matric potential.
5. Seedballs deliver constraining nutrients in the early growing phase.
6. Resulting better root establishment and potassium delivery lead to better water use efficiency and in turn a higher survival rate in case of early drought.
7. Better root density allows to catch nutrients otherwise leached.
8. Higher root density leads to higher total nutrient uptake and early biomass production.
9. Restricted number of plants per sowing pocket reduces workload for thinning.
10. Preparation of seedballs in the off-season is not constrained by work force limitation but relaxes work force bottlenecks in the early rainy season.
11. Seedballs can be combined with other management options, e.g. seed fungicide treatment, additional fertilization.

Suitability

The technology was developed for chemically poor sandy soils of the semi-arid Sahel and pearl millet-based subsistence agriculture with low external inputs. Other applications potentially need technological adaptations.