Optimizing phosphorus requirement of seed potato through organic and inorganic sources in north-west India.

Phosphorus optimization is essential to maximize seed-size potato productivity and reduce the occurrence of over-sized and under-sized tubers. A field experiment was conducted for two years at the two locations in Punjab, India to investigate the effects of organic and inorganic phosphorus management on seed potato productivity. The experiment was conducted in a split-plot design with three organic (farmyard manure, biofertilizer, and control) treatments in main plots and five fertilizer phosphorus (0, 46.9, 62.5, 93.8, and 125 kg/ha P2O5) treatments in subplots. The application of farmyard manure (50 t/ha) resulted in a significant increase in growth and yield attributes, tuber yield, seed size (3.5–4.5 cm) tuber number, and economic returns. The percentage increase in seed size tuber number and tuber yield with farmyard manure over the control was 36.6% and 29.3%, respectively. Among the fertilizer phosphorus levels, the highest growth attributes, tuber yield, seed size tuber number and economic returns were obtained with a 125 kg/ha. The application of 125 kg/ha fertilizer phosphorus resulted in a 36.3% and 23.0% (mean) increase in seed size tuber number and tuber yield compared to the unfertilized phosphorus (0 kg/ha). No significant organic sources x fertilizer phosphorus levels interaction effects were found on any of the traits evaluated at both locations. The result of this study indicates that P management can play an important role in increasing seed size and productivity. [ABSTRACT FROM AUTHOR]