to determine if drip irrigation increases fertilizer requirements and/or the efficiency of utilization compared to furrow irrigation, growth and nitrogen uptake were measured in a four-year experiment comparing surface (sd) and buried (bd) methods of drip irrigation with furrow irrigation (f) of cotton. the soil was a slowly-permeable cracking grey clay (vertisol) at narrabri, n.s.w drip-irrigated treatments were maintained at a deficit of 45 mm below the fully-irrigated soil water content, while f was irrigated when the deficit reached about 90 mm. nitrogen (n) fertilizer was applied weekly with drip irrigation to bd and sd over the first half of the season, and as a conventional single application to f before sowing leaf area index (lai), dry matter and n uptake were influenced more by season than by method of irrigation. the efficiency of conversion of solar radiation into dry matter averaged 0.55 g mj** $minus$ **1; lint yield as a fraction of dry matter averaged 0.18; neither parameter was consistently influenced by the method of irrigation total n uptake ranged from 97 to 170 kg ha** $minus$ **1 and was influenced by irrigation method in one season only, when it was less in f than in sd and bd. additional study results are discussed (edited author abstract) 32 refs