Efficiency of Azolla and Biochar Application on Rice (Oryza sativa L.) Productivity in Salt-Affected Soil

A field experiment was conducted during two successive summer seasons of 2018 and 2019 to investigate the effect of biochar application rate and Azolla application time on rice (Oryza sativa L.) plant productivity under salt affected soils. The obtained data show significant increases of straw and grains yield as well as biological yield (Mg fed-1) as a result of Azolla and biochar application. The treatment of 10 Mg biochar fed-1 and Azolla at rate of 180 kg fed-1 in two equal doses at 0 and 35 days of transplanting was associated with high yields of straw and grains. Nutrients content (%) and uptake (kg fed-1) as well as the relative changes of their uptake by either straw or grains were increased as a result of individual and combined applications of biochar and Azolla. With the same treatment of biochar and Azolla N, P and K content (%) and uptake (kg fed-1) in grains were higher than those found in straw. There is a wide variation in straw and grains content of N, P and K, in response to the studied treatments. Also, in both straw and grains under different fertilization treatments, the content of the determined nutrients takes the order K> N> P. These findings concluded that, reducing of salt stress and increasing productivity of salt affected soils may be achieved through biochar and Azolla application.