Effect of Increasing Doses of NPK on Groundnut Development and Productivity in the Marginal Zone of Southern Chad

The aim of the study was to determine the optimum level of NPK fertilizer on groundnut productivity. The plant material was the Fleur 11 groundnut variety, and the fertilizer used was NPK (12-24-12). The trial was conducted in a Fisher block design with five treatments repeated four times. The treatments applied were T0 (0 kg NPK/ha), T1 (50 kg NPK/ha), T2 (75 kg NPK/ha), T3 (100 kg NPK/ha), T4 (125 kg NPK/ha). Treatment T2 (54.35±2.475) recorded the highest number of leaves per plant at 30 DAS, followed by T4 (54.3±2.1). The lowest number of leaves per plant was observed on T0 (41.6±2.5). Treatment T4 (307±8.5) recorded the highest number of leaves per plant at 60 days, followed by T1 (306.25±10.75). The lowest number of leaves per plant was obtained on T0 (218.5±18). The highest haulm yield was recorded on T3 (0.681 t/ha±0.029) followed by T1 (0.651 t/ha±0.029). The lowest yield was recorded on T0 (0.472 t/ha±0.025). The highest shell yield was obtained on T1 (2.10 t/ha±0.108) followed by T3 (1.96 t/ha±0.573). The lowest yield was recorded on T0 (1.118 t/ha±0.688). The highest weight was recorded on T1 (382.5 g±12.583) followed by T3 (350 g±17.795). The highest weight was recorded on T1 (382.5 g±12.583), followed by T3 (350 g± 17.795). The lowest weight was obtained on T0 (0.204 kg±4.112). The required dose of 50 kg NPK ha-1 (T1) could be recommended to growers to make peanut cultivation more profitable. However, further studies are needed to assess soil organic matter levels prior to fertilizer application, and to optimize cropping techniques likely to further improve groundnut productivity under the experimental conditions.