An index to rate the quality of no-till systems: a conceptual framework.Glaucio Roloff
1. An index to rate the quality of
no-till systems:
a conceptual framework
Glaucio Roloff
Federal University of Latin-American Integration (UNILA)
Ramiro A. T. Lutz
Vetagro Crop Consultants
Ivo Mello
Brazilian No-Till Federation (FEBRAPDP)
Cooperation FEBRAPDP – ITAIPU Binacional
5th WCCA & 3rd FSD
Brisbane 2011
2. No-Till System (NTS): in Brazil
Prevailing system for grains by far, especially within last 15 years
~30 million ha, ~50% of total cropland
Early adopters: an effective soil conservation technique
Current reality:
relatively stable yields and timely seeding
saves fuel and time
more crops over a time period, e.g. ...
soybean/corn/oats (cover) → regular rainfall winters
soybean/corn+Bracchiaria (cover and pasture) → dry winters
5th WCCA & 3rd FSD Brisbane 2011 2
7. NTS: current shortcomings in Brazil
Reasons for the non adherence to key components:
Bollinger et al. (2006) Advances in Agronomy, 91, 47-64
– Farmers...
» …unable to afford cover crops and appropriate herbicides
» …interested only in commercial crops
– Perceived need to till eventually to...
» …alleviate compaction
» …incorporate lime
In addition
– Crop consulting dissociated from sustainability issues
– Agricultural policies dissociated from environmental policies
– Environmental policies ignore positive externalities from NTS
– Erosion and runoff no more seen as a problem
» complacency
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8. NTS in Brazil
Adherence to key components needs to be improved
… and hence improve NTS environmental services
How to gauge adherence?
Through a NTS quality index
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9. NTS in Brazil
CA key components cover all environmental externalities?
• Kassam et al. (2009) International Journal of Agricultural Sustainability, 7, 292–320.
» Ideal CA soil should approach forest floor condition
...hence minimal water runoff (among others)
• Usual NTS conditions far from ideal
» Inappropriate crop rotations → poor soil cover at times
» Compaction
• Rainfall intensities often > stable infiltration rates
» up to yearly run-off events
Run-off management should be an explicit component of any
NTS quality assessment
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10. NTS Quality
NTS Quality
...capacity of a given no-till field to maintain or increase crop and
livestock productivity while maintaining or enhancing soil, water and air
quality and other environmental services.
NTS Quality Index (NTSQI) premises and development
• based on a regional benchmark set of best practices
• constructed from recognisable indicators → self-evaluation
• sampling-free and non seasonal
• specific to NTS
• address directly or indirectly the four key system components
• allow for the recognition of critically low key indicators
• indicators defined by expert opinion and farmers input
5th WCCA & 3rd FSD Brisbane 2011 10
12. NTS Quality Index
NTSQI formulae
Ei Ii = ith indicator
Ii= Ei = current or future parameter value
Bi Bi = benchmark value
NTSQI= ∑ ( Ii∗ fi ) fi = subjective weighing factor
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13. NTS Quality Index
NTSQI test
• 24 voluntary farmers over 6
small river basins
• Questionnaire (assisted
evaluation)
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14. NTS Quality Index
Regionalised NTSQI parameters
Indicator Ei fi Bi Critical
RI Crops past 3 yrs 1.5 9 0.56
RD Crop species past 3 yrs 1.5 4 0.50
RP Grass cover crops past 3 yrs 1.5 6 0.50
TF Whole field tillage operations past 3 yrs 1.5 6 0.50
TA Run-off over-topping events past 5 yrs 1.0 ---- 0.50
Cumulative absence of downhill seeding,
CE whole field and edge compaction signs, and 1.0 4 0.50
visible erosion
BN Cumulative presence of manure addition, soil 1.0 3 0.33
sampling and nutrient balance
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AT Years of no-till adoption 1.0 22 0.33
16. NTS Quality Index
Conclusions:
• NTSQI can be...
» … used to rank farmers and basins to promote awareness.
» … be a tool to prioritise actions to improve NTS quality and
hence of its environmental services.
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