The experiment consisted of six treatments: (i) control (no residues), (ii) NPK (at recommended rate, 38 kg N ha1), (iii) groundnut residues 5 Mg ha1 (120 kg N ha1), (iv) rice straw 5 Mg ha1 (25 kg N ha1), (v) 1:0.5 mixed (groundnut residues 5 Mg: rice straw 2.5 Mg ha1), and (vi) 1:1 mixed (groundnut residues 5 Mg: rice straw 5 Mg ha1). After rice transplanting, samples of the lowland rice cultivar KDML 105 were periodically collected to determine growth and nutrient uptake. At final harvest, dry weight, nutrient contents and 15N recovery of labeled groundnut residues were evaluated