agricultural growth Annock G. Chiwona, Rachel Gaulton & David - - PowerPoint PPT Presentation

Novel potash fertiliser from nepheline syenite for Africa’s agricultural growth

Annock G. Chiwona, Rachel Gaulton & David A.C. Manning

School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne, United Kingdom

Email: a.g.chiwona2@newcastle.ac.uk

Presented at the 35th International Geological Congress 2016, Cape Town, RSA 1

Outline

• Research background
• Africa population vs agriculture dynamics
• Current Project feasibility in Africa
• Study’s Goal and approach
• Initial results
• Achievements so far
• Future work
• Conclusion

2

Research background

(Source: Manning, 2015)

With global population projected to 9billion and 2billion in Africa by 2040, food insecurity likely major problem (Manning, 2015; Sheldrick, Syers & Lingard, 2002)

3

Africa population-agriculture dynamics

• Status of agricultural industry of Africa has not been

as expected for many years.

• Between 1960-1980s only 2% p.a growth in

Agriculture sector (1.85% in crop yields against 3% annual population growth (Larson & Frisvold, 1996).

• Significant decline in per capita growth about 18% (1969 – 1987)

and 10% decline in 1996.

• Nutrient loss due to intensive farming in sub-Saharan about 22kg

N, 2.5 kg P and 15 kg of K per hectare each year in last 30 years (Keeble, 2012).

• Intensification of crop production by increasing soil

fertility through fertiliser use is probably most viable

• ption to achieve food security
• There has been more soil mining than nutrient replenishment

4

What this means for Africa

• Africa, with 15% of global population uses just 1.5% of world's K fertiliser
• Great need for alternative potash sources hence my present research

Malawi

5

K nutrients soil depletion in African countries, (data from Sheldrick et al., 2002).

Project feasibility in Africa

Literature shows Malawi’s Nepheline syenite rocks have similar geochemistry to some areas already tested for fertiliser use.

6

Study’s Goal and approach

Main goal:

• To assess potential of nepheline syenites (Nsy) from rift tectonics,

with initial focus on Malawi, as alternative K fertiliser sources.

7

Materials and Methods

(a) (b)

• Key data include ASTER and SRTM imagery, Malawi’s airborne

geophysical radiometric data to delineate potential areas

8

Spectral response of nepheline syenite

Shows distinct spectral curves in TIR region of electromagnetic spectrum

9

Initial results

10

Overlayed with alkaline intrusion locations (Woolley, 2001).

11

Overlayed with alkaline intrusion locations (Woolley, 2001).

12

Achievements so far

13

• Identified potential areas of

interest from remote sensing and gamma ray data.

• Ground truthing is in progress

– Hand-held gamma ray spectrometry – Most areas surveyed agree with results from remote sensing and airborne geophysical survey results

Future work

• Complete ground truthing of selected

potential areas

– Combined with spectral analyses of rocks and soils

• Conduct petro-geochemical analyses
• Conduct K release studies for nepheline

syenite

• Conduct plant growth experiments

14

Conclusion

• There is greater need to intensify use of fertiliser

for food security and sustainable agricultural sector growth in Africa.

• Agro-geology offers new opportunities for the

fertiliser industry.

• Nepheline syenites from the EARS are promising

for novel, low cost and easy to use silicate K alternatives for Africa.

• Great appreciation to Newcastle University,

Society for Economic Geologists, Terrativa and Malawi Government for the financial and techinical support to the research.

15

Thank you very much

Email: a.g.chiwona2@newcastle.ac.uk

16

References

• Keeble F. 2012. "Food for thought", Nature, vol. 483, no. 7391, pp. 510.
• Larson, B. A. and G. B. Frisvold 1996. "Fertilizers to support agricultural

development in sub-Saharan Africa: What is needed and why." Food Policy, vol. 21 no.6.pp.509-525.

• Manning, D. A. C. 2015. "How will minerals feed the world in 2050?"

Proceedings of the Geologists' Association, vol 126 no.1, pp. 14-17.

• Manning, D. A. C. 2010. "Mineral sources of potassium for plant
• nutrition. A review." Agronomy for Sustainable Development, vol.30 no.

2, pp. 281-294.

• Sheldrick, W. and J. Lingard 2004. "The use of nutrient audits to

determine nutrient balances in Africa." Food Policy, vol. 29, no.1, pp.61- 98.

• Sheldrick, W., et al. 2002. "A conceptual model for conducting nutrient

audits at national, regional, and global scales." Nutrient Cycling in Agroecosystems, Vol 62, no.1 pp.61-72.

• Woolley, A.R. (2001). Alkaline Rocks and Carbonatites of the World. Part

3: Africa. London: Bath.

17