Sustainable agriculture is a prerequisite for food and environmental security. Chemical fertilization, especially nitrogenous fertilization, is considered the most consumed for field crops. In rice crops, plants consume much less than half of the applied N-fertilizer. In the current investigation, multiple N environments were generated by applying different N doses of urea fertilizer to a permanent transplanted field for two successive summer growing seasons at a rice research and training center, Kafrelsheikh, Egypt. A set of 55 genotypes consisting of 25 Jabonica, 4 Tropical Japonica, 20 Indica, and 6 Indica/Japonica were transplanted under no N (0N), Low N (LN), medium N (MN), and High N (HN) (i.e., 0, 48, 96, and 165 Kg N ha−1, respectively). Highly significant differences were detected among the tested genotypes. AMMI analysis of variance revealed the existence of the genotype via nitrogen interaction (GNI) on yield performance. The GNI principal components (IPCA) IPCA1 and IPCA2 scores were significant and contributed values of 71.1 and 21.7, respectively. The highest-ranked genotypes were MTU1010, IR22, SK2046, SK2058, IR66, and Yabani LuLu based on their grain yield means (30.7, 29.9, 29.5, 29.3, 28.8, and 28.5 g plant−1). These genotypes were grouped into the same SCL according to the stability analysis ranking matrix. Based on AMMI analysis and biplots, MTU1010 and Yabani LuLu showed yield stability across environments. Meanwhile, the which-won-where biplot showed that IR22 was superior under unfavorable N-levels and MTU1010 was stable across the different environments. These findings are considered to be of great importance to breeders for initiating low-nitrogen-input breeding programs for sustainable agriculture.

Anhydrous ammonia is a cheaper source of nitrogen (N) fertiliser than granular urea for rice production, but it is not widely used in developing countries. It can only be applied pre-crop with any in-crop applications being applied in the form of urea. This 2-year study conducted in the Nile delta region of Egypt compared pre-crop anhydrous ammonia injected to a depth of 20 cm with broadcast urea as N sources for rice, along with 4 combinations of pre-crop ammonia and in-crop urea. Each treatment supplied a total of 165 kg N/ha. The rice crop was direct seeded rather than transplanted. The highest yields were achieved in the full anhydrous ammonia treatment, which yielded 53% more grain than the nil-N control, while the full urea treatment yielded 22% more than the control; most combination treatments were intermediate. The higher grain yield of the anhydrous ammonia treatment was through a higher panicle density per unit area and more filled grains per panicle. An economic analysis found that the anhydrous ammonia treatment had a net return 70–94% higher than supplying the same quantity of N as urea. Counts of bacteria, fungi and actinomycetes showed a decline by day 2 after injection of anhydrous ammonia, followed by an increase to numbers similar to or above pre-injection levels by day 5. The findings indicated that pre-crop anhydrous ammonia in rice is both economically promising and not deleterious to soil microbes.