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1
Maximizing returns to fertilizer
use on maize in Malawi
Lessons from on-farm agronomic research
Farm Input Subsidy Progr...
2
How can farmers derive maximum
benefits from using fertilizer on
maize? Presentation outline
 Nationwide on-farm ferti...
3
Area-specific fertilizer
recommendations trials, 1995/96 &
1997/98 Single-replicate trials run by
extension FAs
 Plot ...
4
Area-specific fertilizer
recommendations trials, 1995/96 &
1997/98 Planted on farmer’s field
 Farmer managed, with
sup...
5
Agronomic results
 Strong yield response in
maize to fertilizer
 Nitrogen is most limiting nutrient
for maize producti...
6
Agronomic results
 17.7 kg maize per kg N-
applied
 National average linear hybrid
maize yield response
 7.0 to 9.5 k...
7
Phosphorus and Sulphur
 Nitrogen single most
important nutrient limiting
maize yields in Malawi
 However, response to
...
8
Optimal crop management
practices Agronomic ‘rules of thumb’ for profitable and
efficient fertilizer use on maize
 Reg...
9
Agronomic ‘rules of thumb’
(cont.) Weed well
 1996/97 demonstration on this
point at 118 sites
 Weeding twice with ha...
10
Agronomic ‘rules of thumb’
(cont.) Application methods
 1996/97 demonstration at 318
sites to compare methods
 Expec...
11
Agronomic ‘rules of thumb’
(cont.) Soil and within-field variations
 Soil texture useful indicator of fertilizer resp...
12
Organic strategies for soil fertility
management
 Organic residue use reduces need for inorganic fertilizers
 Not all...
Implications for FISP design
 Efficient logistics
 Timeliness in crop operations is a big part of efficient
production
...
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Maximizing returns to fertilizer use on maize in Malawi: Lessons from on-farm agronomic research, by Todd Benson (IFPRI)

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Maximizing returns to fertilizer use on maize in Malawi: Lessons from on-farm agronomic research, by Todd Benson (IFPRI)

  1. 1. 1 Maximizing returns to fertilizer use on maize in Malawi Lessons from on-farm agronomic research Farm Input Subsidy Program (FISP) National Symposium 14-15 July 2014 Lilongwe, Malawi Todd Benson IFPRI
  2. 2. 2 How can farmers derive maximum benefits from using fertilizer on maize? Presentation outline  Nationwide on-farm fertilizer trials on hybrid maize  Activity of the Maize Productivity Task Force of the Ministry of Agriculture in 1995/96 and 1997/98  Results - agronomic response in Malawi  kg maize per kg fertilizer (or kg N) applied  Optimal crop management practices
  3. 3. 3 Area-specific fertilizer recommendations trials, 1995/96 & 1997/98 Single-replicate trials run by extension FAs  Plot treatments were fertilizer packages – bags of fertilizer per ha  Six treatments in 95/96; Four in 97/98  Urea, 23:21:0+4S, & DAP (DAP in 95/96 only)  Second year trial signboard here  MH17 or MH18 hybrid maize
  4. 4. 4 Area-specific fertilizer recommendations trials, 1995/96 & 1997/98 Planted on farmer’s field  Farmer managed, with supervision by FA  Good, consistent crop management  Site selection protocols to avoid confounding factors  Pests, Striga, frequent flooding  Plots not fertilized previous year  Successful - Obtained data for analysis from 83% of sites in first year, 70% in second year
  5. 5. 5 Agronomic results  Strong yield response in maize to fertilizer  Nitrogen is most limiting nutrient for maize production  Yield response to phosphorus varies from area to area  Generally significant responses to sulphur  National quadratic N- response pattern across the two years shown here  In analysis, adjusted trial plot yield values downward to better reflect likely crop performance on larger fields 0 500 1000 1500 2000 2500 3000 3500 0 25 50 75 100 125 Maizeyield(kg/ha) Nitrogen (kg/ha) Y = 1286+ 29.7N– 0.122 N2
  6. 6. 6 Agronomic results  17.7 kg maize per kg N- applied  National average linear hybrid maize yield response  7.0 to 9.5 kg grain per kg fertilizer (urea & 23:21:0+4S)  Highest responses seen in upland areas  Lowest response in Lower Shire Valley  But highest yields without fertilizer  Lakeshore – intermediate and more varied N-response (linear) kg maize per kgN Intercept (no N) kg maize per ha National 17.7 1,430 Karonga ADD 14.4 1,620 Mzuzu ADD 19.0 1,110 Kasungu ADD 19.0 1,330 Lilongwe ADD 19.3 1,440 Salima ADD 19.1 1,550 Machinga ADD 17.8 1,290 Blantyre ADD 17.7 1,600 Shire Valley ADD 11.7 1,860 Note: ADD – Agricultural Development Division
  7. 7. 7 Phosphorus and Sulphur  Nitrogen single most important nutrient limiting maize yields in Malawi  However, response to phosphorus and sulphur over wide areas  1995/96 trial results provided insights here  However, note this is an agronomic assessment  Annual use of P & S fertilizers may not necessarily make economic sense for farmer  In any case, apply with nitrogen Mzuzu Lilongwe Blantyre Zomba Karonga Salima Kasungu Mchinji Chitipa Nsanje Mangochi Mzimba No significant response Signific ant response Zo nes of response to thea pplication of in maize at moderate levels of nitrogen. ,phosphorus and sulphur Comparison of 35:10:0+ 2S (kg N:P0 :K+ S per ha). 2 5 versus35:0:0 Mzuzu Lilongwe Blantyre Zomba Karonga Salima Kasungu Mchinji Chitipa Nsanje Mangochi Mzimba No significant response Signific ant response Comparison of 96:40:0 versus 92:21:0+ 4S. Zones of response to the appli cation of in maize when nitrogen and phosp horus are notlimi ted. ,sulphur
  8. 8. 8 Optimal crop management practices Agronomic ‘rules of thumb’ for profitable and efficient fertilizer use on maize  Regardless of how much fertilizer is applied, farmers must do a good job in growing maize  Use fresh hybrid seed adapted for local conditions  Plant as early as possible  Apply fertilizer on time  Basal dressing immediately after emergence  Apply top-dressing 3 to 4 weeks later  Any further delay and nitrogen in fertilizer increasingly goes to produce stover, not grain
  9. 9. 9 Agronomic ‘rules of thumb’ (cont.) Weed well  1996/97 demonstration on this point at 118 sites  Weeding twice with half fertilizer (Trt 2) gives about same yield as weeding once with full rate (Trt 3)  Economically, net benefits of Trt 2 higher than Trt 3  Reflecting cheaper cost of labour for weeding relative to cost of fertilizer 0 1000 2000 3000 4000 Trt 1 Trt 2 Trt 3 Trt 4 maizeyield(kg/ha) Trt 1 Weed once Apply half recommended fertilizer Trt 2 Weed twice Apply half recommended fertilizer Trt 3 Weed once Apply all recommended fertilizer Trt 4 Weed twice Apply all recommended fertilizer
  10. 10. 10 Agronomic ‘rules of thumb’ (cont.) Application methods  1996/97 demonstration at 318 sites to compare methods  Expected to see no difference in yields, but not the case  Dolloping superior  No statistical yield difference between banding and broadcasting  However, labour requirements differ between methods  When labour constrained, economically could make sense to broadcast 0 1000 2000 3000 4000 B anding D ollopingB roadcasting maizeyield(kg/ha) Banding Sprinkled in groove on side of ridge Dolloping Two holes 10 cm from planting station Broadcasting Spread evenly on ridge top; follow with weeding to cover with soil
  11. 11. 11 Agronomic ‘rules of thumb’ (cont.) Soil and within-field variations  Soil texture useful indicator of fertilizer response  Sandy soils typically less fertile, so respond well to fertilizer when growing conditions are good  Medium-textured soils not as responsive to fertilizer as light-textured soils, but typically less risky  Less affected by drought. Fertilizer does not leach from them as much under heavy rains  “The best and worst parts of a field should not receive fertilizer”  Best areas – locally fertile patches – not very responsive  Worst areas – other problem than soil fertility limit maize yields – termites, Striga (kaufiti), waterlogging, etc.
  12. 12. 12 Organic strategies for soil fertility management  Organic residue use reduces need for inorganic fertilizers  Not all organic sources of value  Grain legume crop residues, khola manure, compost, & prunings from N-fixing shrubs and trees generally good  Maize stover generally not recommended  Grain legume rotations  At higher N:maize price ratios (>4.5), grain legume-maize rotations (e.g., groundnut, soyabean) often provide better financial returns over 2 years than fertilized maize alone  Best rotation crop with maize for soil fertility and increased maize yield is kalongonda (velvetbean)
  13. 13. Implications for FISP design  Efficient logistics  Timeliness in crop operations is a big part of efficient production  Agronomic information to FISP beneficiaries  Extension component to FISP  Many farmers know as much about making effective use of fertilizer as do researchers, but many do not  Targeting  Can identify areas where greater returns from applying fertilizer to hybrid maize can be obtained  Can identify beneficiaries who have assets or labour that will enable higher returns to fertilizer use 13

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