Title: Integrative effect of NPK fertilization and weed management practices on growth indices and yield of wheat under agro-climatic condition of Quetta-Pakistan Muhammad Ayub Babar
Abstract: The inhibitory effect of weeds on crop can be minimized by changing nutrient supply and weed management practices.For this purpose, a field experiments was carried out during 2014-15 at the experimental field of ARI, Quetta based on complete randomized block design in factorial arrangement and were replicated thrice.In the experiment, five fertilizer rates (0-0-0, 100-80-50, 135-90-50, 170-100-50, 205-110-50 NPK kg ha -1 ) were tested across different weed management practices (no weeding, herbicide application, hand hoeing and allelopathic weed control) in an integrated manner.The results showed that the medium fertilizer rate (135-90-50 kg NPK ha -1 ) produced maximum tillers m -2 (437.50),spike length (12.12 cm), spikelets spike -1 (29.08), grain spike -1 (78.33), seed index (42.05g), harvest index (37.7%),grain yield ( 4.51 t ha -1 ), leaf N (3.91%),P (0.94%) and K (4.05) concentration and uptake.The increasing fertilizer rates particularly N increased vegetative growth over reproductive growth as evidenced from higher LA (316.92 cm -2 plant -1 ) and LAI (1.96).In case of weeds management, the herbicide application or hand hoeing effectively controlled weeds by 85.47 and 78.73% that resulted in increased all wheat traits.According to linear regression analysis, grain yield was positively and significantly associated with LAI (r = 0.93), tillers m -2 (r = 0.94), harvest index (r = 0.96), LAD (r = 0.97) and NAR (r = 0.88) respectively.Consequently, weed crop competition was minimized and wheat yield was enhanced when fertilizer rate of 135-90-50 NPK kg ha -1 was used and weeds were controlled either by herbicide application/hand hoeing.