[Digestion] "Pest Repellent property of dilute slurry" - contd

[Hoysall Chanakya]

Dear List users
Many thanks to all who have continued to react and respond to my request. 
With special thanks to Frank Shields, Joe Crescenzi, Jaime Marti Herrero,
Eric Buysman, Isiaka Taiwo, Krishna, Jagadeesh – your inputs are really of
interest.  It has spurred to take up this as a potential project in the
coming months.  In doing so I thought some clarification and Introduction
is in order and therefore this longish response.

I thought I will write a short note about my interest and my exposure to
this option.  It came way back in 1992 working with resource poor farmers
of Tamil Nadu, South India where, just as Eric Busyman indicated, farmers
fermented dilute cattle dung slurry and various local weeds and herbs and
made a pest repellant that they filtered and sprayed as foliar sprays on
crops such as rice-paddy (plant hoppers, paddy butterfly), ground nut (red
hairy caterpillar), cotton (pink boll worms), castor (semi looper – Murali
Krishna talked about – Spodoptera ), flower crops and vegetables such as
tomato, brinjal, Lady fingers, Chilli, etc.  They christened this
decoction “Ural” in Tamil – loosely translated into English as “steepage
/soakage”.  These farmers belonged to the Low External Input and
Sustainable Agriculture (LEISA) network based in Trichy and as Eric
responded, the outcomes were mixed.  My interaction with these farmers
(c.2000 farmers, in 10 districts of TN) circa 1997-2000 indicated roughly
a similar mix of responses as Eric obtained in Thailand.  Alas!! those
were not the days of auto-focus, aim and shoot digital pocket cameras so I
have very little documentation or organized data /study of its effectivity
in the field.

Should any one of you like to get more anecdotal details on diluted cattle
dung slurry fermented with various local leafy materials, I suggest you
could interact directly with kudumbamtry at yahoo.co.in [contact persons
Oswald Quintal and Suresh Kanna].  I stopped taking note of this seriously
when farmers and the network started to change the inputs (circa 2002) and
began to mix fermented whey (dilute butter milk), clarified butter, milk,
and traditional Indian medicinal herbs in small quantities thereby
bringing in a large change in the “possible” active components or
microflora.  Such mixtures and fermented brews are too complex to study
anyway.

Our own researches (at IISc, Bangalore) showed that biogas digester
residue (digestate from non-cattle dung biogas plants) encourage growth of
all types of earth worms and their growth in turn reduce viable counts of
soil borne pathogens such as Rolstonia and Rhizoctonia in our red soils
around Bangalore.  While farmers, who used cattle dung biogas plant slurry
(as dried residue) onto paddy and vegetable nurseries reported fewer
pathogens and very low weeds emerging in their nurseries especially with
paddy and vegetable plots.  Once again we did not document these at that
time.

Circa 2004-2006, the Horticulture Department of Karnataka State (south
India) subsidized a concept of “bioreactor” where weeds and leafy
agro-residues were ‘anaerobically’ fermented in open tanks and the
resultant ‘anaerobic’ leachate was sprayed back on horticulture crops
after diluting 1:5 with water.  This was to serve both as a source of
micro-nutrients as well as a pest repellant.  About Rs25,000 (USD650) was
the subsidy amount provided.  Once again there were no ‘third party’
documentation of the outcomes and effectivity in the field nor were the
active principles identified.

I thought we had missed the bus until I found that use of such pest
repellants is once again growing and becoming popular among organic
markets and it has the potential to grow further.  As organic markets (and
bulk dealers) test samples and ensure absence of pesticide residues, the
use of diluted biogas slurry, I expect will once again become popular
among organic as well as resource poor farmers.

Thank you all.  I will now begin to document such pesticidal and pest
repellant outcomes.  Any additional inputs from you all will be greatly
welcome.
Chanakya



-- 
Dr. Hoysall Chanakya
Centre for Sustainable Technologies
(Assoc. Faculty at Centre for Infrastructure, Sustainable Transport and
Urban Planning (CiSTUP) and Centre for Contemporary Studies)
Indian Institute of Science, Bangalore 560 012
ph 91-80-2293 3046; fax-91 80 2360 0683


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