Greenhouse evaluation of growth parameters related to birdsfoot trefoil and red and white clover production on an and IC mission silt loam

Abstract

Birdsfoot trefoil (Lotus tenius), red clover (Trifolium pratense) and white clover (Trifolium repens) were evaluated as potential forage legumes on andic soils. A greenhouse study was used to evaluate the influence of soil pH on: (1) the establishment and growth of these forage legumes, (2) N and P quantity and concentration, and (3) Rhizobium lupini and Rhizobium trifolii survival. Aluminum sulfate and finely‐ground calcium carbonate were used to adjust soil pH. Soil pH's were 4.8, 5.1, 5.6, 6.2, 6.4, 6.9, 7.0 and 7.4. Birdsfoot trefoil, red clover and white clover were grown in 15 cm pots in the greenhouse and harvested five times at approximately 20‐day intervals. Yield was measured and plant material was analyzed for total N and P. Populations of R. lupini and R. trifolii were monitored using the MPN technique. Manipulation of pH in the Mission soil was found to have a significant effect on the growth of the three forage legumes, tissue N and P concentration and uptake, and on the survival of R. lupini and R. trifolii in the soil. In general, tested parameters increased with increasing soil pH. Greatest forage yield occurred in the 6.9–7.0 pH range. The andic nature of the Mission soil requires a pH adjustment above pH 6.2 for acceptable establishment and yields of the three forage legumes studied. This is in sharp contrast to non‐andic northern Idaho soils where forage legume yields are usually not adversely affectea above pH 5.5. All three legumes appeared to have good potential ana should be evaluated under field conditions.