After tasting success with rubber, root trainer technology adopted for cashew trees

Bovikanam: After proving its worth in rubber nurseries, root trainer technology is now being put to the test in the cashew plantations of Kerala. The Plantation Corporation of Kerala (PCK) has launched a pilot project to produce seedlings with straighter taproots that could grow into stronger, more wind-resistant trees.

As part of the trial, PCK has raised 1,500 grafted seedlings of the Priyanka and Dharashree cashew varieties at its nursery in Muthalappara near Muliyar. Instead of being sold, the seedlings will be planted in the corporation's own farms to assess their performance under field conditions.

Unlike conventional nursery practices, where seedlings raised in plastic grow bags develop curled taproots after reaching the bottom of the bag, the root trainer system encourages the taproot to grow straight down. The seedlings are raised in specially designed, foot-long plastic containers with a tapered base that resemble elongated ice cream cups.

These containers are mounted on iron stands that allow unrestricted root growth. The result is a more robust tap root system that provides better anchorage, which makes the trees less vulnerable to strong winds while also improving their ability to absorb water and nutrients.The initiative assumes significance in light of the extensive damage caused by strong winds at PCK's Mannarkkad estate in 2020, which saw a large number of cashew trees uprooted.

The corporation produces more than two lakh seedlings every year, most of them in disposable plastic grow bags. Replacing the bags with reusable root trainer containers is expected to make nursery operations more environmentally sustainable.

While the root trainer system has already been adopted in rubber cultivation, this is the first time it is being tested for cashew in Kerala, said U Sajeev, Malabar Group Manager of PCK, who is leading the initiative.