54 Papaya
responsive to mechanical stimuli and show strong thigmomorphic responses or touch-
regulated phenotypes (Porter et al. 2009). These responses could be essential to the
success of papaya in harsh, early successional sites exposed to high winds because
it triggers hardening mechanisms that result in compact architecture, increased lig-
nification and the formation of petiole cork outgrowths (Clemente and Marler 2001).
Therefore, for proper establishment of papaya plantation, it is better to grow under
shelterbelt with full sunshine. Staking, earthing up and wind break can decrease the
damage to plants from strong winds.
3.3 Soil
Papayas grow and produce well on a wide variety of soils. The trees often develop
a strong taproot shortly after planting. Under favourable conditions the root system
can penetrate soil up to a depth of 2 m, but most of the roots responsible for nutrient
uptake are found in the top 50 cm of soil, with higher concentrations in the top 25 cm
soils. Well-drained sandy loam soil with adequate organic matter is most important
for papaya cultivation. On rich organic soils, papaya makes lush growth and bears
heavily, but fruits are of low quality (DAIS 2009). Well-drained soils of uniform
texture are highly preferable to avoid collar rot disease too. In a high rainfall area, if
drainage is poor and roots are continuously drenched for 24–48 h, it may lead to the
death of the plants. Sticky and heavy soils are not suitable as rainwater may accumu-
late in the soil even if it rains only for a few hours. In such cases, higher raised bed
and drainage ditch are recommended (Figure 3.1).
A well-drained/upland field is selected for cultivation, as shown in Figure 3.1.
The growing field should be well levelled and kept at a suitable soil moisture that is
FIGURE 3.1 (See colour insert.) Raised beds for papaya plantation.