Organic management of Chinese potato: growth, yield, quality, soil health, and economics

Abstract

There is a preference for organic vegetables, including Chinese potato [Plectranthus rotundifolius (Poir.) Spreng. or Solenostemon rotundifolius (Poir.) J.K. Morton], due to concerns regarding plant health, safe food, and sustainable yields. However, organic technologies in this crop is lacking. Comparison of crop growth, biomass production, yield, quality, soil properties, nutrient uptake, and cost-benefit analysis between organic and conventional systems in Chinese potato has not been thoroughly investigated. Field experiments were done from 2014 to 2016 at the Indian Council of Agricultural Research-Central Tuber Crops Research Institute, Thiruvananthapuram, India, to assess differences due to conventional (I1); integration of animal manure, chemical fertilizers and plant growth-promoting rhizobacteria (I2), and organic treatments, traditional farmer practice comprised animal manure @ 15 t·ha−1 and ash @ 2 t·ha−1 (O1); use of animal manure @ 10 t·ha−1, green manure @ 10–15 t·ha−1, neem cake @ 1 t·ha−1 and ash @ 2 t·ha−1 (O2), and organic + plant growth- promoting rhizobacteria as above, but instead of ash the bacterium Azospirillum, and a P and K solubilizer @ 3 kg∙ha−1 (O3) were examined for effects on productivity, tuber quality, soil productivity,and economics of production of Chinese potato. Organic management improved biomass partitioning to tubers, harvest index, higher pH ( + 1.14, + 0.23 unit), organic C ( + 15%, + 21.33%), available N and P, tuber K, P and Zn uptake over conventional and integrated practices, respectively. Tuber yield, gross income (avg. US$7777.13∙ha−1), and profit (avg. US$5721.80∙ha−1), were unaffected. Organic production may be an alternative for Chinese potato with responses equal to conventional production while possibly delivering improved soil health.