Parallel session 2 2 evaluation of agronomic practices on growth, yield of cassava_omolara
- 1. A research activity update on Evaluation of agronomic practices on growth, yield of cassava and soil physical properties in southwestern Nigeria Olabisi Omolara Onasanya A PhD Project within the Africa Cassava Agronomy Initiative on the “Best Planting Practices” use case
- 2. Overall Objective • Provide site-specific recommendations on agronomic practices in cassava systems to conserve soil while maintaining high cassava yields in Nigeria. Introduction • Tillage is the physical, chemical or biological soil manipulation to optimize conditions for seed germination, emergence and seedling establishment, BUT • Tillage may either be beneficial or detrimental to the soil over time • Hence, it is important to look into improved agronomic practices in combination with tillage that will best conserve the soil under cassava systems
- 3. Agronomic practices and cassava growth, root yield and quality • To investigate the effects of basic tillage(ploughing), shaping the soil surface (ridging), weed control and fertilizer application on the establishment, growth, root yield and quality of cassava Tillage intensity and soil aggregate stability • To evaluate the impact of tillage intensity on soil aggregate stability, soil C and N in particle size fractions and determine their relationship with cassava yield Tillage Intensity and least limiting water range • To determine the effect of tillage on soil strength, compaction and the least limiting water range and relationship between physical- hydraulic properties and cassava root yield Specific objectives
- 4. Experimental Setup • Study in Oyo and Ogun State, Nigeria over 2 years (2017 and 2018) • Researcher Managed Trials (RMTs) established in Saki, Ido and Odeda Local government areas (2nd year ongoing)
- 5. Experimental design and layout
- 6. Climatic and soil variations of sites where Researcher Managed Trials (2017) were installed Location Soil depth (cm) pH O.C Total N P (ppm) % Sand % Silt % Clay Ca Mg K Na C mol/kg Odeda 0-20 6.7 0.88 0.079 4.35 65 17 18 3.85 1.5 0.16 0.12 20-50 6.7 0.54 0.037 1.67 66 18 16 1.69 0.67 0.08 0.13 Ido 0-20 6.6 0.92 0.081 2.14 65 13 22 3.89 1.29 0.19 0.06 20-50 6.5 0.64 0.06 6.57 65 15 20 3.02 1.03 0.14 0.07 Saki 0-20 6.6 0.36 0.038 2.3 65 17 18 1.64 0.5 0.08 0.09 20-50 6.5 0.44 0.036 2.14 60 18 22 1.78 0.57 0.1 0.2 Local Government Area Agro ecological zone Parent material * Average annual temperature (OC) *Average annual rainfall (mm) Ido Southern guinea savannah Basement complex 22.9 – 24.4 1136 - 1341 Odeda Derived savannah Sandstone 26.1 – 27.8 1136 - 1341 Saki Derived savannah Basement complex 22.9 – 24.4 934 - 1136 * data from year 1950- 2000
- 7. Task 1: Cassava measurements to address the effects of agronomic practices • Sprout count • Plant height • Number of main stems per plant • Number of leaf (scars and alive) per plant • Light interception: 12 & 24 • Fresh root mass per plot • Root number and diameter • Dry matter content of roots • Number of bad (rot) roots per plot • Starch content 4, 8, 12, 16, 24 & 48 weeks after planting 48 weeks (harvest)
- 8. Germinationcount Zero plough Single plough flat ridge flat ridge Year 2: 2018Year 1: 2017 p.value ds$basicTillage 0.00000 ds$soilShape 0.00001 Year 0.18463 No significant interactions Effect of tillage intensity on cassava germination at 4 weeks after planting
- 9. Effect of tillage intensity on cassava germination at 4 weeks after planting by experimental sites
- 10. p.value Treatment 0.01 Location 0.02 Treatment:Location 0.98072 Mean Group Ido 185.97 A Odeda 92.47 B Saki 46.68 B Treatment Mean Group SP-RG-HB-F1 125.80 A SP-RG-FC-F1 124.31 AB SP-FL-FC-F1 120.99 ABC SP-FL-HB-F1 117.84 ABC ZP-RG-HB-F1 115.49 ABC ZP-RG-FC-F1 115.41 ABC SP-RG-HB-F0 114.69 ABC ZP-FL-HB-F1 112.80 ABC SP-RG-FC-F0 111.03 ABCD SP-FL-HB-F0 110.99 ABCD ZP-FL-FC-F1 105.56 ABCDE ZP-RG-HB-F0 102.56 BCDE SP-FL-FC-F0 101.59 CDE ZP-RG-FC-F0 99.78 CDE ZP-FL-FC-F0 88.76 DE ZP-FL-HB-F0 82.94 E Response and variation of cassava plant height (cm) to treatment SP: Single Plough ZP: Zero Plough FL: Flat RG: Ridge HB: Herbicide control FC: Farmer’s control (hoe weeding) F1: Fertilized F0:Unfertilized KEYS
- 11. Cassava height progression weeks after planting by experimental sites
- 12. Treatment Mean Group 1 SinglePlough:Ridge:Farmerschoice:Fertilized 22.36 A 2 SinglePlough:Ridge:Herbicide:Unfertilized 18.51 AB 3 SinglePlough:Ridge:Herbicide:Fertilized 18.42 AB 4 SinglePlough:Flat:Farmerschoice:Fertilized 16.95 BC 5 SinglePlough:Ridge:Farmerschoice:Unfertilized 16.71 BCD 6 SinglePlough:Flat:Farmerschoice:Unfertilized 15.47 BCDE 7 ZeroPlough:Ridge:Herbicide:Fertilized 14.28 BCDEF 8 ZeroPlough:Ridge:Farmerschoice:Unfertilized 14.06 BCDEF 9 SinglePlough:Flat:Herbicide:Unfertilized 13.81 CDEF 10 ZeroPlough:Ridge:Farmerschoice:Fertilized 13.39 CDEF 11 SinglePlough:Flat:Herbicide:Fertilized 12.63 DEF 12 ZeroPlough:Flat:Herbicide:Fertilized 11.38 EF 13 ZeroPlough:Flat:Farmerschoice:Fertilized 10.13 FG 14 ZeroPlough:Ridge:Herbicide:Unfertilized 10.13 FG 15 ZeroPlough:Flat:Farmerschoice:Unfertilized 9.78 FG 16 ZeroPlough:Flat:Herbicide:Unfertilized 5.99 G Treatment effects on cassava root yield (t/ha)
- 13. Cassava root yield (t/ha) relative to treatment by experimental sites
- 14. • The sieves were immersed in water and moved vertically by 2 cm height amplitude at 60 oscillations per minute • The soil fraction left on each sieve was recovered, dried to 0% moisture and weighed to calculate the mean weight diameter (MWD)Soil samples were air-dried and passed through an 8 mm sieve before wet sieving with stacks of sieves (2 mm, 0.25 mm, and 0.053 mm) Task 2: Evaluating the effect of basic tillage and soil shaping on aggregate stability Van Bavel, 1949MWD = σ𝑖 𝑛 𝑋𝑖𝑤𝑖 Xi= mean diameter of each size fraction Wi = proportion of the total sample weight corresponding size fraction
- 15. Mean weight diameter in response to tillage intensity as growth progresses
- 16. Soil aggregate size distribution after being subjected to tillage intensities At establishment At harvest Mass(g) Mass(g)Tillage intensities Tillage intensities SP: Single plough ZP: Zero plough FL: Flat RG: Ridge
- 17. At establishment At harvest Carboncontent(%)Carboncontent(%) Nitrogencontent(%)Nitrogencontent(%) At establishment At harvest Carbon and nitrogen content (%) in individual soil fraction at establishment and harvest
- 18. Task 3: Observations to study the effect of tillage intensity on soil strength, compaction and cassava yield • Penetrologger is used to measure the resistance of soil to penetration as a proxy for soil strength and compaction. • Soil resistance to penetration is dependent on soil moisture content.
- 19. 0 -10 cm 10 -20 cm 20 -30 cm OdedaIdoSaki Changes in penetration resistance with depth weeks after planting following different tillage intensities SP: single plough ZP: zero plough FL: flat RG: ridge
- 20. Preliminary conclusions………… • Zero plough reduced germination count in both years of experiment, as well as planting in flat land. • Basic tillage influenced fertilizer response to root yield. • Across locations, zero plough increased mean weight diameter and decreased resistance to penetration • Treatment response to yield was location dependent as inherent soil properties play a distinct role