Instructions for collection of soil and grain samples for

Transcription

Instructions for collection of soil and grain samples for
Instructions for collection of soil
and grain samples for testing
aflasafeTM efficacy
To sample Aspergillus flavus communities resident in an environment,
we routinely sample soil from the top 2 cm of the topsoil and grains. Soil
samples may also be collected to track the aflasafeTM strains released in
the field for their ability to move and displace the toxigenic strains. The
procedures and pattern of sample collection vary based on the type of
data needed. However, the general protocol for sampling of soil, maize,
and groundnut grain is outlined here.
www.iita.org
Instructions
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Position the collectors at one end of the field. The number of
people involved in the collection may depend on the size of the
field or availability of labor.
Collect soil samples before aflasafeTM application and grain
samples at harvest.
Walk along the rows (see diagram below) in the field, scoop the
topsoil, and select the ears or groundnut plants after every 5
paces at intervals of 5 to 10 rows until the whole field is covered.
The composite soil sample should be a collection from at least 15
different spots in the field weighing about 500 grams.
Collect soil samples (scoop 3 to 5 grams) from the top 2-cm
depth with a tablespoon before aflasafeTM application.
Moist or wet soils must be placed in a forced-air drying oven at
40oC as soon as possible after sampling. If oven is not available,
dry the soil samples in an aerated place under shade.
If crop samples are collected in the standing crop at maturity,
select 25 maize cobs or 25 groundnut stands from the control
and treated fields of each farmer based on the sampling plan
below.
If crop samples are collected from stacked harvest, select 25 maize
ears or 25 groundnut plants from the control and treated field of
each farmer.
Position the collectors at the beginning of
the plot at 5 to 10 row’ interval depending
on the size of the field.
Move along the maize or groundnut rows
in the field and collect soil or maize ears
after five paces as marked in the diagram.
Collecting soil samples in maize field.
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Collecting maize cobs from harvested and stacked crop in the field.
• Do not collect grain samples from the border rows. Leave a minimum
of 4 meters from the borders of the field while collecting maize ears or
groundnut stands.
• After analysis, feedback on aflatoxin and fungal analyses will be
returned to the farmers in 6 and 8 months’ time, respectively.
• Record the coordinates for each farmer’s field along with the identity
of the farmer (name, village, Local Government Area, State), previous
crop, tillage method, maize variety, and type and amount of fertilizer
used.
• Also record dates of planting, inoculum application, flowering,
harvesting, and mode of storage after harvest.
• Use polyethylene bags to collect and dispatch the samples. Put one
sample label inside the bag and paste or attach a written label on the
exterior of the bag.
• Label all soil and grain samples properly with the farmer’s name,
location, and date and send to Pathology Unit, IITA, Ibadan, for
aflatoxin and fungal analyses.
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About IITA
IITA is an internationally funded, not-for-profit research-for-development institute with
headquarters in Ibadan, Nigeria. IITA was created 1967 by the Federal Government of
Nigeria through a government decree and is recognized as an international organization
diplomatic privileges. We conduct research, development, training, and information
with
exchange activities in partnership with regional and national programs in sub-Saharan
Africa
to improve the productivity, profitability, and sustainability of maize, soybean,
cowpea,
cassava, yam, and banana/plantain systems for the benefit of poor farmers.
What is aflatoxin?
Aflatoxin is a poison produced by aflatoxin-producing strains of the fungus Aspergillus
flavus. This fungus resides in the soil and dead/decaying matter in the field. Aflatoxin
contaminates maize, groundnut, and other crops produced. It is very dangerous to
humans and animals. There are other A. flavus strains in nature that do not produce
aflatoxins (called atoxigenic strains).
How was aflasafeTM developed?
aflasafeTM was developed by IITA in collaboration with the Agriculture Research Service
of the United States Department of Agriculture, University of Bonn, and University
of Ibadan. We isolated more than 4,200 strains of Aspergillus species from naturally
infected maize ears collected from maize fields and farmers’ stores in Nigeria. After five
years of careful and painstaking research using microbiological and molecular biology
methods, we identified 12 atoxigenic strains out of which four strains were tested for two
years in experimental fields in four sites. aflasafeTM reduced aflatoxin concentration in
maize by 60 to 99% in these trials.
What is aflasafeTM and how does it work?
• The biocompetitive product aflasafeTM is a mixture
of four natural atoxigenic strains of A. flavus.
• These atoxigenic strains are allowed to internally
“colonize” sorghum grains for a brief period and
dried. aflasafeTM externally looks like cooked
sorghum grain, and internally contains a very
small amount (a few nanograms) of the four
atoxigenic strains.
aflasafeTM in 10-kg boxes.
Aflasafe in 10 kg boxes
• After application, the atoxigenic strains in
TM
aflasafe produce a large number of spores on sorghum grains, a food source it
owns, and competitively displaces toxic strains of A. flavus. This leads to significant
reduction in aflatoxin concentration in crops harvested from treated fields.
TM
How will aflasafeTM benefit Nigeria?
aflasafeTM will significantly reduce aflatoxin concentration in agricultural products, thus
contributing to the improvement of health of the Nigerian people and provide safer
products. As efforts to revamp exports gather momentum, aflasafeTM will help ensure
acceptance of Nigerian products in the international and regional markets.
For more information, contact Dr Ranajit Bandyopadhyay,
IITA, PMB 5320, Ibadan, Nigeria
Email: [email protected] or [email protected]
Mobile: +234 806 868 1854 or +234 803 978 4000
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