Nitrogen Use Efficiency (NUE) in tomato (Solanum lycopersicum) seedlings in response to treatment with extract of Cymbopogon citratus and mineralization of Tithonia diversifolia leaves and cow dung

The aim of this work was to study the effect of Cymbopogon citratus extract on nitrogen metabolism in relation to the increase of Nitrogen Use efficiency (NUE) in tomato plants. The culture substrates (δ) were prepared with fertilizations of 15g N and 5g N following the formula: δ + tomato plants + treatments (2%). Treatments included, Hydro Ethanol Extract (HEE) of C. citratus (2%), 2% Ridomil (R) and Control (C). The tomato seedlings were transplanted 32 days after sowing and (δ) sampled 12th, 24th, 36th and 48th days after transplanting and the following parameters determined: Total nitrogen, Electrical Conductivity (EC (dS/m)), Total Mineral content (TM (ppm)), pH water, nitrate (NO3- (ppm)), ammonium (NH4+ (ppm)) and NUE (kg-1 DM), using these techniques: Kjedahl, Electrochemistry, Spectrophotometry. The results from the dosage of N revealed that Tithonia diversifolia (Ti), Cow dung (Cd), soil/sand (2:1) mixture and NPK contained 3.32%, 2.13%, 0.23 %, and 23.00% of N respectively. The kinetics of mineralization in the δTi, δCd showed a primary mineralization while that in the δNPK and δC showed a secondary mineralization. The values of NUENPKHEE, NUENPKR, NUETiHEE, NUETiR, NUECdHEE, and NUECdR increased by 38.49%; 37.45%; 27.74%; 52.07%; 93.93%; 70.52%, respectively. The combination of plant spray with HEE of C. citratus and soil amendment with T. diversifolia or cow dung improved significantly the NUE of tomato plants confirming that T. diversifolia and cow dung are slow mineralization nitrogenous biofertilisers.