Peach palm - World Agroforestry Centre

Promoting the conservation and use of underutilized and neglected crops. 20. 47
production may decline in time, primarily owing to shading, which limits new
offshoot development, and competition for water and nutrients. At lower plant
densities, production is suboptimal during the early years because above- and
belowground resources are not fully utilized. One might consider planting at
higher density for maximum production during the first years, and then thinning
plants and/or reducing the number of stems per plant progressively in the
following years. The production potential and economic costs/benefits of this
progressive thinning approach have not been fully quantified. Under some
conditions farmers may not adopt a progressive thinning approach. Most farmers
interviewed in the Peruvian Amazon Basin prefer to sow perennial plants at final density;
they are reluctant to sow them at high densities and then thin to a lower density (Brodie et
al. 1997). This is well accepted in Costa Rica, however, where this thinning approach is
becoming a common practice (J. Mora-Urpí, pers. observ.). Agricultural extension
programmes may change farmers’ attitudes in some regions.
Some research on plant densities and spatial arrangements for heart-of-palm
production has been conducted. When interpreting results of these experiments, three factors
should be kept in mind: production during the first years may not be a reliable indicator of
later production; nutrient inputs are necessary to maintain high production over time (see
Section 9.5); landraces, and perhaps plants within landraces, may respond differently to
management treatments and environmental conditions (e.g. plant density, number of stems
per plant, local soil, climate and fertilization).
Sowing at higher plant densities can produce higher heart-of-palm yields during the
first years, but production may fall in subsequent years if plants are not properly managed.
For example, Chalá (1993) and Játiva (pers. comm.) evaluated yield at eight plant densities
for 5 years in northeastern Ecuador, using local peach palm seed. Chalá (1993) observed
the highest second-year yield at the highest density tested, 16 666 plants/ha (Fig. 7, H). The
fifth-year yield (M. Játiva, unpublished data) was greater than the second-year yield in plots
with 8888 or fewer plants/ha (greatest increase at the lowest density) but was lower in plots
with 10 000 or more plants/ha (sharpest decline at highest density). Plants in the highestdensity
plots produced thin hearts-of-palm, indicating the need for thinning. Densities of
8888 or more plants/ha were established by sowing 2 or 4 plants/site. If each of these 2 or
4 plants/site produced a single stem per year, the total number of stems would be equal to
a plantation sown with half as many plants but managed for 2 or 4 stems per plant per year.
In this study, the highest yield in the fifth year was at 1.5 x 1.5 m spacing with 2 plants/site,
but this was only slightly greater at that age than the yield at 1.5 x 1.5 m spacing with 1 plant/
site. The number of stems per plant and fertilization schedule were not reported. The
cumulative increase in yield (approx. 1.75 t in 5 years) may cover the additional cost
of producing, planting, managing and harvesting the 4444 extra plants/ha used. In
Costa Rica, with the Utilis landrace and fertile soils, the most common density has
changed from 5000 plants/ha (2 x 1 m spacing; 1 plant/site) to 10 000 plants/ha (2.0
x 0.5 m spacing; 1 plant/site), although multiple plants per site are sometimes used. Lower
plant densities are recommended for soils of lower fertility (Mora-Urpí 1984).
There are two different approaches to managing offshoots for heart-of-palm: not