Rational Nitrogen Strategies Can Improve Peanut Source Supply Capacity and Pod Yield

Core Ideas N4 treatment gained the highest yield and nitrogen use efficiency. N4 treatment delayed the senescence of leaf blades in the late developmental stage. N4 treatment improved photosynthetic function in the late development stage. N4 treatment enhanced source supply capacity for peanut seed filling. Peanuts in the northern peanut production area of China should be fertigated with N4. Peanut ( Arachis hypogaea L.) is an important oil crop in China. Its cultivated area is about 4850 kha and production is about 17,700 kt in 2016, they both account for the first in the world. During peanut production in China, N fertilizer is applied one time as basal fertilizer, this causes overproduction during vegetative growth and early leaf senescence in the reproductive stage, resulting in decreased pod yield. Therefore, this study was conducted to evaluate peanut pod yield under different N fertilizer strategies. Five N fertilizer treatments with three replications were applied: N1: 180 kg ha −1 as basal fertilizer; N2: 90 kg ha −1 as basal fertilizer and 90 kg ha −1 top dressing at R3 stage (beginning of active pegging and fruit development stage); N3: 90 kg ha −1 as basal fertilizer and 90 kg ha −1 at R6 (the beginning of the seed filling stage); N4: 90 kg ha −1 at R3 and 90 kg ha −1 at R6 and Control: no N fertilizer applied. Results indicated that rational fertilization strategies caused peanut population growth to be more coordinated, senescence of the leaf blade was delayed at the later development stages, which enhanced source supply capacity for peanut yield and provided ample photosynthate for enrichment of seeds, increasing yield. As a result, N4 treatment produced the highest yield and nitrogen use efficiency (NUE), while these were lowest in response to N1 treatment. These results indicate that peanut should be fertilized as for N4 in higher soil N condition.