A presentation at the WCCA 2011 event in Brisbane.

1. Termite Prevalence and Crop Lodging under
Conservation Agriculture in Semi-arid Zimbabwe
By
Eleanor F Mutsamba, Nyagumbo, I, and Mafongoya, P.M
Dpt of SSAE-UZ
CIRAD

2. Introduction
Benefits of termites: food, improve soil properties
Benefits of crop residues:
 Opinions on retention of crop residues
• retention of crop residues contribute to increased termite
prevalence thus lodging in semi-arid regions.
• the presence of dry crop residues may actually reduce termite
attack on growing crops
 Q. At what residue application rate can they reduce termite
attack on crop if applied at the start of the season?
 This study therefore sought to establish the linkage between
termite prevalence, crop residues, crop lodging and crop yields.

3. Specific objectives
• To establish the influence of surface applied crop residues on
termite prevalence in CA systems
• To determine the contribution of crop residues applied as a
surface mulch to crop damage by termites in CA systems.

4. Materials and Methods
project site: Kadoma (NRIII)
 Field lay out:
• A Complete Randomised Block Design (CRBD) experiment
• 5 treatments of (0, 2, 4 and 6 t ha-1 of crop residues under CA)
and a control (conventional mouldboard ploughing treatment), 4
replicates per treatment per farmer.
• Maize residues used

5. Methodology cont…..
 Sampling procedures
• soil monoliths measuring 20 cm x 20 cm x 20 cm depth
were used sample termites
• Crop damage was assessed by counting number of
lodged plants by termites in each plot. Result expressed
as % of total plants

6. RESULTS

7. Table 1: Effects of different residue amounts under CA on termite abundance (per m2 of
soil) compared to under CMP
a
2008/9 2009/10
Treatments
CA- 0t/ha residue cover 300 a 283 a
CA- 2t/ha residue cover 2100 b 263 a
CA -4t/ha residue cover 3050 b 1179 b
CA- 6t/ha residue cover 2662 b 1121 b
CMP 25 a 358 a
LSD 1724 612
Means followed by the same letters in a column do not significantly differ at 5% level,
LSD test

8. Table 2: Percentages of lodged crops under CA at different residue amounts compared to
CMP.
a
Means followed by the same letters in a column do not significantly differ at 5% level,
LSD test

9. Table 3: Crop yield (kg/ha) under CA with different residue amounts compared to
CMP
2008/09 2009/10
Treatments
CA- 0t/ha 2900 a 2348 a
CA- 2t/ha 3055 a 2814 c
CA- 4t/ha 3034 a 2693 bc
CA- 6t/ha 3348 a 2756 bc
CMP 2117 b 2570 ab
LSD 750 222
Means followed by the same letters in a column and within site do not significantly differ at 5% level, LSD test

10. Discussion
Significance at 4t/ha to CMP wrt termite numbers:
• residues attract termites and act as food source
• Tillage disturbs termites’ channels and nesting
sites

11. Discussion
• No trend in crop lodging as residue amount
increases: by time of harvest all termites were
already finished.
• Lower lodging on CMP compared to CA could
confirm that tillage disturbs termites channels
• Lodging in maize reached about 40 % which is
too high
• The inconsistence of yield under CA as crop
residues app. rate increases was also observed
by CIMMYT, Zim
•

12. Conclusion
• Increasing crop residues under CA increased termite
numbers with highest peak at 4t/ha.
• Addition of crop residues did not necessarily reduce
crop lodging in a notable pattern. This is so because
by the time of physiological maturity, all the residues
would have been finished.
• Increasing crop residues had no sign. effect on yield at
least in the short term

13. Recommendations
• there is need for termite control and early
harvesting in t.i.a.
• Need for long term (>2 years) local studies

14. Thank you
Thank you