Impact of Azolla caroliniana and A. pinnata as soil amendments on Rotylenchulus reniformis and plant growth of cowpea in Egypt

Two Azolla species, Azolla caroliniana and A. pinnata were evaluated throughout twosuccessive seasons (2015 & 2016) as green manures on Rotylenchulus reniformis andplant growth of cowpea cv. Baladi under greenhouse conditions (25±5°C). Thesubstrates were applied at the rates of 25 and 50 gm of dry material of each species /pot. The use of A. caroliniana and A. pinnata significantly (P = 0.05, 0.01 levels)succeeded in reducing the number of swollen females and number of egg-layingfemales and also significantly (P = 0.05, 0.01 levels) improved cowpea growth whencompared with those of the check. The use of A. pinnata significantly (P = 0.05, 0.01levels) reduced the number of swollen females and number of egg-laying females perplant, at both rates, when compared to A. caroliniana. Also, the growth of cowpeaplants was affected due to the application of Azolla. Addition of Azolla to the plantcaused a remarkable increase in the cowpea growth. The higher dose of each Azollaspecies was significantly (P = 0.05, 0.01 levels) more effective than the lower one. Ingeneral, the use of dry materials of A. pinnata resulted in increase in the plant growth,more than A. caroliniana.

Keywords:

Azolla , Nematode , Soil amendments , Rotylenchulus reniformis , Cowpea