Evaluation of potato (Solanum tuberosum) cultivars for productivity, nitrogen requirement and eco-friendly indices under different nitrogen levels

A field experiment was conducted during the winter ( rabi) seasons of 201112 and 201213 at Adisaptagram Block Seed Farm, Hooghly, West Bengal, to optimize the potato ( Solanum tuberosum L ) cultivars and nitrogen lev- . els for growth attributes, tuber yield, nitrogen-use efficiency, sustainability, eco-friendliness and economics in new . alluvial zone of West Bengal. Fifteen treatment combinations, viz 3 potato cultivars (Kufri Himalini, Kufri Shailja and Kufri Jyoti) and 5 N doses (0, 75, 150, 225 and 300 kg N/ha) were laid out in a factorial randomized block de- sign with 4 replications. Kufri Himalini recorded the maximum tuber yield (31.3 t/ha), which was significantly higher than Kufri Shailja (26.6 t/ha) and Kufri Jyoti (24.1 t/ha). Correlation between tuber yield and plant height (R2=0.73), tuber yield and dry matter accumulation (R2=0.84), tuber yield and tuber bulking rate (R2=0.75) and tu- ber yield and total N uptake (R2=0.62) were significant. The correlation study between nitrogen and tuber yield showed high degree of correlation (R2=0.984) and N was derived as 202.6 kg N/ha for optimum economic yield. opt. Agronomic efficiency (AE ) and physiological efficiency (PE ) was more in Kufri Himalini at all N levels. There was N N a positive balance of nitrogen in all the treatments except one treatment (Kufri Jyoti with 300 kg N/ha). Kufri Himalini fertilized with 300 kg N/ha gave the highest net returns ( 1,45,156/ha) and benefit: cost ratio (2.58) with least difference from 225 kg N/ha, while the negative response was recorded in the control. Kufri Shailja potato was more eco-friendly, as its index was 18.4% higher than Kufri Jyoti. Kufri Shailja required 18.4% less applica- tion of fertilizer N to give the highest yield obtained by Kufri Jyoti (30.94 t/ha). So, for obtaining a given yield, less amount of fertilizer is being put to soil and hence comparatively less amount of N is being lost to the environment.