Effect of soil temperature on nodulation and developement of perennial soybeans (Glycine javanica L.)

Abstract

A greenhouse experiment was carried out to study the influence of soil temperature and nitrogen source on the establishment of the legume-Rhizobium symbiosis and plant growth of five varieties of perennial soybeans (Glycine javanica). The interacion temperature x nitrogen source was highly significant for plant dry weight, total plant nitrogen and nodule weight and number, demonstrating specific temperature effects on the plants depending on symbiotic nitrogen fixation. The plant growth in the treatments with mineral nitrogen was stimulated with increased temperature (up to 40ºC daily maxima), whereas nodulation, nitrogen percentage and total nitrogen in the plants dependent on symbiotic fixation decreased at these temperatures. Maximal nitrogen fixation was obtained at the intermediate temperature treatment where the daily maxima varied between 30 and 36° C, during the first month. The five varieties of perennial soybeans reacted in the same way.