The excessive application of synthetic fertilizers can result in severe environmental risks, while composting green and fresh feedstocks can provide slow-release nutrients. Therefore, the aim of the current investigation was to study the effects of eight individual and combination treatments of azolla compost and NPK synthetic fertilizers (control = no fertilizer and compost; 100% NPK = full recommended dose of synthetic fertilizers as follows: 165 kg N ha⁻¹, 37 kg P₂O₅ ha⁻¹ and 50 kg K₂O ha⁻¹; 70% NPK; 40% NPK; 100% azolla compost (5 t DM ha⁻¹); 50% NPK + 50% azolla compost; 70% NPK + 30% azolla compost and 40% NPK + 60% azolla compost) on rice growth, productivity and nutrient uptake in semi-arid agro-ecosystems. The results indicated that the combination of 40% NPK + 60% azolla compost or 50% NPK + 50% azolla compost resulted in the most optimal growth and the highest yield components. In addition, the application of 40% NPK + 60% azolla compost exhibited similar rice grain yields (10.76 t ha⁻¹) as well as N, P, and K content and uptake compared with the full recommended dose of NPK fertilizer (100% NPK). This study declared that the utilization of azolla compost as an individual or combination application can reduce usage of synthetic fertilizers by up to 60% without significant reduction in the growth and grain productivity of rice.

Stability analysis for some Egyptian rice cultivars was studied in this paper to identify high-yielding stable rice varieties and to determine their suitable areas as well as their adaptability to different climatic and topographic conditions. A field experiments for ten rice varieties were evaluated by designing randomized complete block with three replications in five successive years (2016-2020) at three Agricultural Research Stations (Sakha, Gemmiza and Zarzoura) in Egypt. Result of ANOVA analysis showed high significance in the studied cultivars, environment and genotype-environment interaction indicated that there is genetic diversity among the cultivars yield. Based on the performance of the rice cultivars across the locations, highly promising for grain yield among cultivars studied, the cultivars Giza 178, Sakha 103, Sakha 104, Sakha 101 and Sakha 106 were considered stable and adapted under different environments. Furthermore, the results indicated that studied cultivars slightly differ in their response to the various environmental conditions, which suggested the importance of cultivars assessment under many environments due to identification the best genetic make up for a particular environment.