574
Cultural Practices
4.1 Intercultural Operations
Papaya orchards should be free from unwanted plants or weeds for better growth
and development. Weeds must be controlled, especially during the initial stages of
orchard establishment. Use of herbicide, hand weeding, mulching and deep hoeing,
either singly or in combination is recommended during the first year to check weed
growth. Weeding should be done on regular basis, especially around the plants.
Applications of Fluchloralin or Alachlor or Butachlor (2.0 g/ha) 2 months after
transplanting can effectively control the weeds for a period of 4 months. Mixture
of oryzalin + oxyfluorfen is a broad spectrum herbicide which is used in papaya
fields for weed management, but the use of oryzalin is safe around young plants
but should not be applied to green stems. Oxyfluorfen is also effective as a pre-
emergence with sufficient irrigation, but sometimes causes vapour drift to recently
emerged leaves. Use of cover crops can also be a practical method to control weeds.
Mechanical cultivation between rows is appropriate to disturb the shallow roots.
The organic material such as crop residues, farm yard manure, by-product of the
timber industry may be used with 5–15 cm layer and keep mulch 30 cm away from
the trunk. Inorganic materials such as plastic films of different colours and thick-
nesses are used efficiently. Mulching in papaya helps by reducing soil compaction,
soil erosion, leaching of fertilisers, winter injury, weed problems, retain soil mois-
ture and improve the quality of produce. Papaya plants are dependent on mycor-
rhizas for their nutrition and benefit from soil mulching and appropriate drainage
that facilitate biotic interactions in the rhizosphere and water and nutrient uptake,
especially phosphorus and nitrogen (Jimenez et al. 2014). Four genera and 11 spe-
cies of arbuscular mycorrhizal fungi have been reported associated with papaya
roots: Glomus, Acaulospora and Gigaspora, among others (Khade et al. 2010).
Mycorrhizal interactions of male and female papaya plants may differ: females
seem more responsive to changes in soil fertility and readily adjust mycorrhizal
colonisation accordingly (Vega-Frutis and Guevara 2009). Among different mulch-
ing material and methods, namely organic mulch, plastic mulch, bare soil with
mounding and flat ground methods, the best treatment combination was plastic
mulch with mounding, which significantly differs from the remaining for manage-
ment of phytophthora (root rot) disease.
4.2 Earthing Up
Earthing up is done three times, for example, after 4th, 6th and 8th months of trans-
planting, before the onset of monsoon and after ensuring one plant per pit, to avoid
overcrowding or water logging. Earthing up in 30 cm radius around the plants also