Gap filling

Gap filling should be done within 15 days after planting preferably with longer setts of 40 cm length. Sree Visakha is a choice variety recommended as an intercrop in coconut gardens. Optimum plant population is 8000 plants per ha with 90 x 90 cm spacing.

Manuring

Cattle manure or compost may be applied at 12.5 t/ha during the preparation of land or while filling up the pits so as to provide about 1 kg of organic manure per plant. Apply fertilizers N:P₂O₅:K₂O at the rates (kg/ha) shown below:

N and K₂O may be applied in three split doses, i.e., 1/3 basal, 1/3 two months after planting and 1/3 three months after planting. Dose of P2O5 can be reduced to half where the crop is grown for more than 3 years under full dose of recommended fertilizers, since under such situation there would be build up of soil P.

For August-September planted tapioca, apply half N, full P₂O₅ and half K₂O basally with first digging and weeding. The remaining quantity of N and K₂O may be applied 45 days after planting at the time of intercultivation.

Note: N:P₂O₅:K₂O at 50:50:100 kg/ha is recommended for Sree Visakam when grown as an intercrop in coconut garden. Higher levels of N tend to increase HCN content of the tubers.Soil application of Mg as MgSO₄ @ 20kg/ha and Zn as ZnSO₄ @ 12.5 kg/ha in small channels around the mounds within 2 months of planting cassava providing an interval of 2 weeks between the application of these fertilizers enhance tuber yield and quality.

Irrigation

Under conditions of well-distributed rainfall, tapioca grows well as a rainfed crop and irrigation is not necessary. However, the crop has to be irrigated to provide sufficient moisture under conditions of prolonged dry periods after planting. Furrow irrigation and alternate furrow irrigation methods can be adopted to irrigate tapioca. Alternate furrow irrigation once in 20-27 days helps to save water and labour with out affecting yield. When the crop is grown under irrigation, yield increase of 150-200% over the rainfed crop has been observed.

Weed control

Keep the field free of weeds and maintain soil loose by 2-3 shallow diggings or hoeing up to 90 days after planting followed by light earthing up. Retain two shoots on each plant in opposite directions and remove excess shoots about 30 days after planting.

Intercropping

Tapioca is planted at a spacing of 90 x 90 cm and it takes about 3-3.5 months time to have enough canopy to cover the land. So it is possible to have an intercrop of groundnut during the early stages of tapioca crop. Bunch varieties like TMV-2, TMV-7, TG-3, TG-14 and Spanish improved are preferred for intercropping in tapioca. The best season for sowing groundnut is May-June.

Immediately after planting of tapioca setts, groundnut seeds are sown at a spacing of 30 cm between rows and 20 cm within rows, so that two rows of groundnut can be accommodated in between two rows of cassava. A seed rate of 40-50 kg/ha is recommended for dibbling one seed per hill. Only well-matured and bold seeds are to be selected for sowing. In acid laterite soils of Kerala, apply 1000 kg/ha of lime as basal dressing. A basal dose of 50:100:50 kg N:P₂O₅:K₂O per ha should be given uniformly to both the crops. One month after sowing of the seed, 20 kg each P₂O₅ and K₂O and 10 kg N / ha may be given to the intercrop along with earthing up. Once pod formation has started (i.e., 40-45 days after sowing) the soil should not be disturbed, as it will affect the pod development adversely. The groundnut crop matures in 105 to 110 days. After the harvest of pods, the haulms are incorporated in the soil along with a top dressing of 50 kg each of N and K2O per ha for the main crop. By adopting this practice, 20-25% additional income can be obtained.

In sandy areas intercropping tapioca with cowpea / groundnut / black gram / green gram may be recommended giving a spacing of 20 cm on both sides of the ridges. The non-trailing grain cowpea variety V-26 is recommended as a companion crop along with tapioca. For a pure crop of tapioca or for a cropping system involving tapioca as the main crop and the pulse crop suggested above, the field may be irrigated once in 36 days to a depth of 5 cm. This recommendation is for shallow water table situations. For deep water table situations, the crop may be irrigated once in 24 days to a depth of 5 cm.