Major nutrient fluxes and water use efficiency of winter vegetables under peri-urban farming of north-western Punjab, Pakistan

摘要

Major nutrient fluxes in urban and peri-urban agriculture (UPA) under semi-arid conditions in north-west of Pakistan are not fully known. To envisage it, a field study was carried out in Faisalabad, Pakistan. Three fertilizers treatments (an unfertilized Control, F0; farm yard manure, FYM (F1) at 14.2 t dry matter (DM) ha -1 containing 108 kg Nitrogen (N), 27kg Phosphorus (P) and a mineral fertilizer treatment (F2) containing the same amount of N and P as in F1 were established during 2011-12. Fertilizer treatments were factorally combined with two irrigation levels i.e. RI; recommended irrigation when irrigation was applied weekly and HRI; half than recommended irrigation where irrigation was applied fortnightly. Subplots randomized within each main plot were assigned to either of the two vegetable species pea ( Pisum sativum L.), cauliflower ( Brassica oleracea L.). Highest crop dry matter yields ( p 0.05) were recorded for pea (12 t ha -1 ) under F2 and lowest for cauliflower in RI (6.2 t ha -1 ) under F1 treatment, respectively. Dry matter yields of both crops were reduced to 11-18% by reducing applying half of the HRI presumably due to water stress. Contrarily, water use efficiencies of both crops were significantly (32-36%) higher under HRI treatment than under RI. Apparent nutrient use efficiencies for C, N, P and K varied widely ranged from 27- 34%. However partial nutrient balances of major nutrients specially for K, remained negative. These results indicate large K mining in the soil which required proper balancing.