Potato production through bio-resources: Long-term effects on tuber productivity, quality, carbon sequestration and soil health in temperate Himalayas

• FYM + CFRDF + MC realized highest total & marketable tuber yield, quality and soil biology.
• FYM + CFRDF + MC produced large grade tuber ( > 75 g) yield (44.2%).
• Higher C sequestration, SMBC and CO2 evolution by using FYM @ 25 t ha−1 + MC.
• FYM + CFRDF + MC, a best option for tuber productivity, nutrient acquisition and soil health in temperate soils.

A field study was conducted on potato crop during summer (April–July) seasons of 2007 to 2011 in temperate north–western Himalayas to evaluate the effects of three different organic manure sources [Farm yard manure (FYM)/chicken manure (CM)/vermicompost (VC)] alongwith microbial consortia (MC) as well as their combinations on tuber productivity, tuber quality and soil health. This five years’ study clearly revealed that application of FYM @ 10 t ha−1 + chemical fertilizers to meet remaining recommended fertilizer dose (CFRDF) + MC proved as a better combination with respect to growth, yield attributes, total tuber yield (23.4 t ha−1), marketable tuber yield (22.2 t ha−1), large grade tuber (>75 g) yield (44.2%), profitability (net returns, Indian Rs. 161599 ha−1; benefit: cost ratio (3.72), tuber quality, NPK uptake, available NPK and soil microbiological properties; which was followed by the application of CM @ 7.5 t ha−1 + MC. However, soil organic matter (SOC) storage (24.7 Mg C ha−1), SOC retention (15.8 Mg C ha−1), soil microbial biomass carbon (SMBC) (376.4 μg g−1 soil), and CO2 evolution (180 μg g−1 soil hr−1) were significantly higher using FYM @ 25 t ha−1 + MC, followed by FYM @ 10 t ha−1 + CM @ 2.5 t ha−1 + VC @ 2.5 t ha−1 + MC over rest of the treatments. Interestingly, sole application of organics in this exhaustive crop is not enough in realizing sufficient marketable tuber yield even on long–term basis in temperate Himalayan soils where mineralization rate is quite slow and inappropriate to meet the nutrient needs of the crop. Thus, application of FYM @ 10 t ha−1 + chemical fertilizers to meet remaining RDF + microbial consortia is the better combination under such agro–ecologies for enhancing nutrient supplying capacity and soil health for sustaining long–term potato productivity and profitability with better tuber quality in diverse NW Himalayan potato production systems and similar socio–agro–economic conditions in temperate world.