Effects of waterlogging treatment on growth and nitrogen fixation of tropical forage legumes, genus Aeschynomene and Macroptilium

The aim of this work was to clarify the effects of waterlogging treatment on growth and nitrogen fixation of Aeschynomene (A. americana L. cv. Glenn, A. americana L. CPI93574, A. americana L. CPIlO6906, A. villosa L. CPI91209 and A. villosa L. CPI93621) and Macroptilium (M. lathyroides (L.) Urb. cv. Murray.. phasey bean and M. atropurpureum (DC.) Urb. cv. Siratro., siratro). Plants were established in pots containing sandy soil. Experiment was conducted from the seven days after germination till 37 days and these 30 days of period was divided into 3 periods of 10 days. Five waterlogging treatments, 0-10th day (I period), 10-20th day (II period), 20-30th day (III period), 0-30th day (long period) and 0 day (no waterlogging as control), were provided. Dry matter yield and nitrogen fixation activity of plants were measured on the 0, 10, 20 and 30th day after the start of waterlogging treatment. Nitrogen contents in the plant of long period waterlogging treatment were determined on the 30th day. In both I and II periods of waterlogging, plant growth of all species were higher than those of control. In the III period waterlogging, plant growth of all species were similar to those of control. In the long period waterlogging, plant growth of phasey bean, Glenn, 93574 and 106906 were significantly higher (P0.05) than those of control during the experimental period. But, plant growth of siratro showed decreases with long period waterlogging treatment, when compared with control. Results of growth analysis revealed that net assimilation rate (NAR) and/or leaf area ratio (LAR) in all waterlogging treatments of Aeschynomene and phasey bean were higher than those of respective control. Nitrogen fixation activity and nodule dry matter weight in all the waterlogging treatments of Aeschynomene and phasey bean were higher than those of control