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Soil Fertility, SRI and
Sustainability
Kishan Rao Parcha
SRI-System of Root Intensification
System of Root Intensification-SRI
system of rice intensification-sri
system of wheat intensification-swi
SRI
• In SRI, the roots of the plant, be it rice or
wheat, spread wide and deep and
efficiently metabolise nutrients, help
tillering and give out strong stems and
large leaves.
• In a non-chemical environment, the roots
thrive and proliferate in the presence of
‘humus’ and friendly microbes.
Fertile Soils
Fertile Soil with Optimum Moisture
Humus( Nutrients, Microbes and
Micro Nutrients, including Minerals)
Optimum spacing of plants - lateral & deeper expansion of roots
Photosynthesis(Energy)
Mining nutrients and minerals
Carrying Capacity of the Soil & the trade-off
Bigger Crop Yields
Depletion of Nutrients and Minerals
About Depletion of Nutrients
It was vividly brought out in the deliberations that the
major factor responsible for the low and
declining crop response to the fertilizers was the
continuous nutrient mining of the Indian soils
without adequate replenishment to the desired extent. It
is estimated that about 28 Mt of
primary plant nutrients are removed annually by crops in
India, while only 18 Mt or even less are
applied as fertilizer, leaving a net negative balance of
about 10 Mt of primary plant nutrients
(NPK).
http://www.naasindia.org/Policy%20Papers/policy%2035.
pdf
About Rice-Wheat Cropping Pattern
Of late, concerns have been expressed
that the rice-wheat growing areas are
developing a so-called “fatigue”, due to
continuous uninterrupted cultivation of this
very exhaustive cereal-cereal (rice-wheat)
cropping system, for now nearly three
decades. There is no doubt that rice and
wheat, which have similar adventitious
rooting systems, are very heavy feeders of
plant nutrients.
‘SRI’ results in more depletion!
(PSI farm, Dehradun, November 2006)
Variety
Type 3
SRI
No of Hills
16
No. of Total Tillers
189
No of Grains per
93
Panicle(Avg)
Total Weight
1800
(chaff+grain) gms
Total Weight of Grains
Net Weight of Grains gms 390
Weight of unfilled grains
Weight of Chaff -gms
1410
Height of Chaff -cm
130
Type 3 Pusa
SRI
Sugandha
Traditional
20
Pusa
Pusa
Sugandha Sugandh
Traditional a SRI
117
24
146
121
23
158
96
16
210
193
3000
2000
2000
3500
450
420
30
2500
110
460
400
60
1540
110
390
380
10
1610
120
720
650
70
2780
140
1 hectare=10,000 m2
1 m2 = 550 gm(Net Weight of Grains)= 5.5 Tonnes/Hectare;
2000 gm = 20 tonnes/hectare
‘swi’, going by the positive outcomes
of PSI trials, also results in even
more depletion of remaining
nutrients in the soil.
The Implications…..
•In the long run, the soil fertility goes down and
along with that, the yields
•The mineral deficiencies will make the
plants/crop weak and disease prone
•The food grains will be deficient in vital minerals
and, in turn, affect the consumers’ health
adversely
•This rice-wheat cropping cycle, year after year, is
unsustainable, be it SRI or traditional(organic) or
traditional(chemical)
Then, what is the solution?
That is...
Replenishment
Through
Green Manure & Compost
Or
Application of Macro & Micro Nutrients
(Chemicals, in a balanced way)
The ‘Replenishment Doctrine’ is
* One crop for the Soil
and
(only then)
* One crop for Us
Is it practical/feasible?
Provided we find enough time and
the ‘will’, for a
green-manure crop
between
Rice & Wheat
and, then,
Wheat & Rice
The Farmers and Scientists know that….
SOWING TIME: Under irrigated conditions, the first
fortnight of November is considered to be the
optimum time for sowing the medium long-duration
wheats, e.g. 'kalyansona' all over India. For shortduration varieties, e.g. 'Sonalika', the second
fortnight of November is the optimum time. In
eastern India, the sowing of wheat is often delayed
owing to the late harvesting of paddy. The sowings in
such cases may go up to even the third week of
December.
http://www.krishiworld.com/html/field_crops2.html
And also…..
In north- western India also, wheat sowings get
delayed due to late harvesting of paddy or
sugarcane or potato. However, wheat sowings
beyond the rain fed conditions, the second half
of October is the optimum time. The sowing of
wheat, when the temperatures are high results in
a poor stand, poor tillering, attack by rootinfecting fungi and pests and the early onset of
flowering. All these factors depress yield. The
success of rainfed wheat depends on the amount
of conserved moisture in the soil.
Conclusion
If sustainable yields and nutritional security are to be
achieved on a priority basis,
we need to proactively intervene and cultivate green manure
crops(preferably, Multi Variety Seed Sowing Technique) in
between the two cereal crops, Rice & Wheat.
The soils, presently, are on the brink of collapse all over the
country.
The present and future populations/generations would have
some chance of survival only if the soils are restored, made
healthy and fertile.
Thank You