1Central Potato Research Station, Jalandhar-144 003, (Punjab).
2Central Potato Research Institute, Shimla-171 001, (Himachal Pradesh).
Long term experiment was conducted on alluvial soil of Jalandhar from 1970 to 1987 with five cropping systems: i) potato-wheat-maize; ii) potato-potato-maize, iii) potato-wheat-paddy; iv) potato-potato-maize-wheat-GM and v) wheat-GM-potato-potato-maize and ten manuring schedules. Soil analysis after 17 years showed that growing of paddy in place of maize in kharif in potato-wheat-paddy/maize systems maintained higher pH, bulk density up to 40 cm soil depth and higher availability of Fe but decreased the availability of K and Mn in soil. Cultivation of autumn potato-spring potato-maize system increased pH, and exchangeable and non-exchangeable K in the soil but lowered the availability of Fe over potato wheat-paddy system. The cereals including wheat, paddy and maize exhausted non-exchangeable reserves of soil K more than the potato did. The green manuring (GM) improved availability of N, P, K, Zn, Fe and Mn in the soil but not of Cu. Farmyard manure (30 t/ha) maintained higher status of macro as well as micro-nutrients in the soil than the combined use of phosphate and potash each at 100 kg/ha and consequently showed higher residual effect on the potato crop raised in 18th year of experiment. The residual effect was in line with organic carbon and available P and K status of soil as maintained by different treatments and was in accord with the nutrients applied in the past.
