Impact of organic management on yield, quality and economics of Chinese potato (Plectranthus rotundifolius)

A field experiment was conducted during August-December, 2011 at College of Agriculture, Vellayani, Thiruvananthapuram, Kerala to standardize technologies for organic production of Chinese potato (Plectranthus rotundifolius Spreng.). The treatments consisted of factorial combinations of 3 levels of organic manure (to supply 100%, 75% and 50% recommended dose of 60, 60 and 100 kg N, P and K/ha), 2 levels of biofertilizer (with PGPR mix 1 and without biofertilizer) and 2 varieties (‘Sree Dhara’ and ‘Suphala’). The trial was laid out in 3 × 2 × 2 asymmetrical factorial randomized block design with 3 replications. Neem-cake @ 1 t/ha and farmyard manure @ 10 t/ha were applied uniformly to all the plots. Application of PGPR mix 1 exerted profound influence on yield, yield components and net income. Variety ‘Sree Dhara’ dominated over the var. ‘Suphala’ in yield, yield components and profit. Tuber yield showed an increasing trend with incremental doses of organic manure, resulting in the highest yield with 100% level. Application of PGPR mix 1 improved the yield. Higher net income and benefit: cost ratio could be obtained by the application of 100% or 75% level of organic manure. Thus, an application of 100% recommended dose of N, P and K (60, 60 and 100 kg/ha) through organic manures (6 t farmyard manure + 3 t coirpith compost + 3 t wood ash/ha) along with PGPR mix 1 and the recommended basal dose of farmyard manure @ 10 t/ha is necessary for getting higher yields of organic Chinese potato.