Influence of Weed Control and Fertility Levels on the Productivity of Seed Potato Under Lahaul Valley Conditions of Himachal Pradesh

A field experiment comprising 12 treatment combinations of four weed control methods (atrazine at 1.0 kg ha−1, isoproturon at 1.25 kg ha−1, pendimethalin at 1.2 kg ha−1 and farmer's practice) and three fertility levels (N50P50K25. N75P75K375 and N100P100K50) was conducted at Kukumseri during four consecutive summers of 2000, 2001, 2002 and 2003. Pendimethalin at 1.2 kg ha−1 was very effective against Digitaria sanguinalis. While atrazine at 1.0 kg ha−1 gave lowest count of Amaranth sp. Atrazine recorded lowest total weed dry matter and significantly higher tubers plant−1, tuber yield (32.5 t ha−1), net return (Rs. 93232 ha−1) and B: C ratio (2.53). Pendimethalin and isoproturon were equally good in influencing seed potato yield. Increase in fertility level increased number of tubers, tuber weight plant−1 and tuber yield significantly. 100 kg N, 100 kg P2O5 and 50 kg K2O resulted in 18.6% higher yield and thereby tended to fetch Rs. 18564 more net returns ha-1 as compared to 50 kg N, 50 kg P2O5 and 25 kg K2O ha-1.