A long-term experiment to study the effects of different rates of nitrogen (N), phosphorus (P) and potassium (K) in intensive rice monoculture commenced at the farmers fields of central Punjab, during growing seasons of 2006–07 and 2007–08. Five fine rice cultivars, B-Super, B-2002, B-kernal, B-2000 and B-385 were used as test crop on normal characteristics bearing loam soils with RCBD plot arrangements. Different levels of NPK with control were assigned in randomized complete block design with 4 dispersed replications. Paddy yields, increase in yield, gross return (GR), net return (NR), value cost ratio (VCR) and grain nutrient ratio (GNR) were recorded. Average of two years study reveals that a considerable response of rice to N, P and K was observed. Compiled results indicated that fertilizer nutrient dose that maximized paddy yield (4.550 t/ha) with increase in yield of 2.863 t/ha was 135-135-60 kg ha-1 NPK, respectively. However, NPK level 135-90-0 kg ha-1 appeared economical with NR (Rs.22095 per ha), VCR 2.7 and GNR 10.4. Quantum of response was found greater for N and P. On the other hand comparison of mean paddy yields of cultivars showed that B- super, gave significantly higher yield followed by, B-385, B-kernel, B-2000 and B-2002.
NPK levels, Paddy yield, Punjab zone, Rice cultivars, Grains per panicle
