A multivariate approach to the response of lucerne plants to varying soil conditions in pots

Abstract

Five levels of lime, five levels of P and a constant level of K were applied to soil in pots to create a range of soil conditions. Factor analysis was used to relate a number of soil test variables to a few factors. Seventeen of the eighteen recorded soil variables were closely correlated with six factors. The six factors described gradients of (1) lime, (2) P, (3) effective cation exchange capacity and Mn saturation, (4) Fe and Mn, (5) Zn, and (6) K. Lucerne plants were established in pots with similar soil conditions and their production was related to the soil gradients. Leaf production responded linearly to the lime gradient and root production to the ECEC/Mn saturation gradient. Stem production responded non‐linearly to the phosphate gradient, a peak observed around 27 mg kg⁻¹ P in the soil. The production of nodules was not related to any of the soil gradients.