Field Guide of Discovery-based Exercises for - Aseanipm ...

Exercise No. 3.26 104
THINNING AS A CULTURAL MANAGEMENT STRATEGY
IN IMPROVING ORGANIC CARROT PRODUCTION
BaCKGroUND aND raTIoNalE
Carrot (Daucus carota) is among the top high-valued crops
that grow well in high elevations, ranging from 1,200-7,400
m above sea level. In the Cordilleras, carrot is directly
seeded in beds either by furrow or drill method. In some
areas, carrot seeds are broadcast in newly harrowed fields.
Optimum yield is achieved when crop is planted in sandy
loam soils where appropriate cultural management practices
are followed throughout its growing period.
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Field Guide of Discovery-based Exercises for Organic Vegetable Production
when is this exercise most
appropriate?
ɶ In FFS, TOT, and VST
sessions, during weeding
operations at early
seedling stages of carrots
in learning field; and
ɶ When farmers want to
learn improved thinning
practices from other
farmers for carrot
seedlings.
One popular cultural management practice employed in organic growing of carrot is thinning. 105
Thinning out of undesirable plant ease out overcrowding of seedlings, which allows better penetration
of sunlight, permits proper aeration or more rapid drying of dew or rain on foliage after a downpour,
and minimizes nutrient competition. For better results, thinning operation is done in two to three
stages depending on sowing density. In carrots, proper timing and methods are as important as
frequency of thinning operations. The decision of whether to do one-time or staggered thinning
operations is often dictated by seedling density and crop stand. Improper thinning often results to
poor quality carrot roots due to forking and cracking, significant yield loss, and consequently lowers
profit.
Through years of experiences, some farmers had made innovations, which led to better thinning
practices, resulting in better crop productivity. These experiences must be shared with other farmers
in FFSs to continuously develop better practices, which will further improve productivity, hence,
this exercise.
104 Adapted from Callo, Jr., D.P., L.B. Teofilo, and H.A. Tauli (eds). 2002. Field Guide of Discovery-based Exercises for Vegetable IPM, Volume II. SEAMEO
Regional Center for Graduate Study and Research in Agriculture (SEARCA), Los Baños, Laguna, Philippines. pp131-133.
105 Kudan, S.L. 1998. As cited in: Callo, Jr., D.P., L.B. Teofilo, and H.A. Tauli (eds). 2002. Field Guide of Discovery-based Exercises for Vegetable IPM,
Volume II. SEAMEO Regional Center for Graduate Study and Research in Agriculture (SEARCA), Los Baños, Laguna, Philippines. 366p.