Influence of nitrogen fertilization on lettuce yields (Lactuca sativa L.) using the 15N isotope label
¹National High School, Department of Rural Engineering, El–Harrach, DZ16004 Algiers, Algeria
²University of Saad Dahlab, Faculty of Nature and life sciences, Department of biotechnology, Ouled Yaïch, DZ09000 Blida, Algeria
³Division of Bioclimatology and Agricultural Hydraulic, National Institute for Agricultural Research, El–Harrach, DZ16004 Algiers, Algeria
Nitrogen fertilization plays an important role in the growth of market gardening and the improvement of yields. Its efficiency of use is imperative for the preservation of the agricultural environment. An experiment is carried out over three consecutive years (2014/2015), (2015/2016) and (2016/2017), in a sub humid climate. The methodology adopted focuses on the variation of optimal nitrogen doses and their effects on the evolution of lettuce cultivation (Lactuca sativa L.), which has a socio-economic impact. The approach takes into account the isotopic marking technique, 15N. The experimental device adopted is of the complete random block type, with four (04) levels: 0 (control), 60, 120 and 180 kg N ha-1 with four (04) repetitions. These levels are used to diagnose the effect of different doses on biomass (dry matter) and yield. It has been shown those doses between 0 and 120 kg N ha-1 increase significantly (p < 0.05), yields and dry matter with values of 18.32, 45.49 to 57.93 t ha-1 and 4.32, 5.52 to 9.77 t ha-1, respectively. The rate of 120 kg N ha-1, is shown statistically, as the efficient rate to cover the nitrogen needs of lettuce. This efficiency reaches 74.48%. Beyond that, nitrogen is not valorized by the crop. These results contribute to the realization of a technical reference system for lettuce cultivation, for an efficient use of nitrogen.