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Nodulation, N 2 Fixation, and Seed Yield of Navy Beans as Influenced by Inoculant Rate and Inoculant Carrier 1
Author(s) -
Sparrow S. D.,
Ham G. E.
Publication year - 1983
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1983.00021962007500010006x
Subject(s) - microbial inoculant , rhizobia , loam , agronomy , biology , inoculation , rhizobium , sowing , arachis hypogaea , population , horticulture , nitrogen fixation , soil water , bacteria , genetics , ecology , demography , sociology
Peat is the most commonly used carrier of Rhizobium sp. (rhizobia) in inoculants. The lack of suitable local peat in many areas of the world leads to interest in other materials as carriers of rhizobia. The purposes of these studies were 1) to compare potential carriers of Rhizobium phaseoli for their ability, under field conditions, to supply viable rhizobia to promote nodulation, N 2 fixation, and increased seed yield of navy beans ( Phaseolus vulgaris L.), and 2) to determine the optimum rate of inoculation with Rhizobium phaseoli to promote nodulation, N 2 fixation, and increased seed yield of navy beans in two soils in Minnesota, a loamy sand (sandy, mixed, Udorthentic Haploborall) and a silt loam (fine‐silty over sandy, mixed, mesic Typic Hapludoll). In 1978, five inoculation rates (ranging from 1 to 10 8 cells/ cm of row) of liquid suspensions of R. phaseoli inoculants were applied at planting. In 1979, R. phaseoli in six inoculant carriers, peat, charcoal, vermiculite, corn ( Zea mays L.) cobs, peanut ( Arachis hypogaea L.) hulls, and liquid medium, was used to inoculate navy beans at rates of 2.5 ✕ 10 4 and 5 ✕ 10 6 cells/cm of row. Nodule numbers and weight, acetylene reduction rates, seed yield, and seed N percentage were determined. In 1978, in most parameters measured, inoculation rates of 10 5 —10 6 cells/ cm were required for a statistically significant increase over the lowest inoculation rate. In 1979 there was no effect of inoculation on a soil with a relatively high population of soil R. phaseoli (10 4 cells/g soil) and relatively high mineral N content (30 ppm). On a soil with an indigenous population of <10 cells/g soil and mineral N content of 8 ppm, peat and charcoal inoculants resulted in the highest seed yield, nodule numbers and weight, and acetylene reduction rates. Peanut hulls and corn cobs gave the poorest responses. These results indicate that peat, charcoal, and vermiculite can be successfully used as carriers of R. phaseoli but peanut hulls and corn cobs are unsatisfactory.