EFFECTS OF SEED INOCULATION METHODS WITH PEAT-BASED RHIZOBIUM MELILOTI ON ALFALFA

Abstract

Saranac alfalfa (Medicago sativa L.) was grown on Charlottetown fine sandy loam (CHFSL) and Culloden sandy loam (CSL) in the greenhouse and field. Uninoculated, inoculated with peat-based rhizobia (I), inoculated and molybdenum-treated (IMo), inoculated and lime-coated (ILC), and inoculated, lime-coated and Mo-treated (ILCMo) seeds were included. At soil pH 5.0 and 5.3 in the greenhouse, the dry weights of alfalfa ranged from 214 to 727 mg/plant in the four cuttings from the ILC and ILCMo seed. The dry weights of alfalfa from the I and IMo seed were 1.3 to 99.7% of those from the ILCMo seed. Alfalfa from the ILC and ILCMo seed was well nodulated, whereas I and IMo seed resulted in poor nodulation. The 1973 field experiment showed that ILC and ILCMo seed at soil pH 5.5 and 5.6 resulted in alfalfa dry matter (DM) yields of 4,050 and 4,830 kg/ha which were equal to DM yields from plots with a pH of 6.0 and 6.1 seeded with inoculated seed. In plots with pH 5.5 and 5.6, total DM yields from I and IMo seed were 26.0–49.7% lower than those from ILCMo seed. In 1972, seed treatments on CHFSL at pH 5.6 did not influence the DM yields of alfalfa, whereas on CSL at pH 5.2 the crop failed to establish except from ILC and ILCMo seed and in limed plots at pH 5.9. In the first cutting, high N concentrations of alfalfa tissue coincided with good growth and good nodulation. The Mo concentrations of alfalfa tissue were not influenced in a uniform manner by seed treatments and varied from 0.11 to 0.49 ppm in the first cut tissue.