Comparative effects of calcium carbonate on growth, nodulation, and chemical composition of four Leucaena leucocephala lines, Macroptilium lathyroides and Lotononis bainesii

Abstract

The comparative effects of CaCO3 on growth, nodulation and chemical composition were determined in four Leucaena leucocephala lines (three bred), Macroptilium lathyroides and Lotononis bainesii grown in pots of an acid soil. Calcium carbonate treatments were equivalent to nil, 250, 750, 1250 and 2500 kg ha-1 (Ca0 to Ca4). L. leucocephala is a tree, well adapted to calcareous soils. M. lathyroides and L. bainesii are herbaceous species tolerant of acid soil conditions. Total dry matter production (tops+roots) of the four Leucaena lines exceeded that of M. lathyroides and L. bainesii. However, the top DM yield of the latter two species exceeded that of Leucaena due to a low top/root weight ratio in Leucaena. The Leucaena lines gave successive total DM increases up to the Ca3 treatment, the overall increase being relatively large, especially in line 3 ;at Ca4 mean DM yieldswere below those at Ca,. Both M. lathyroides and L. bainesii had significant responses particularly at the Ca1 treatment, but at the Ca4 treatment their total DM yields were reduced below those obtained with no CaCO3 addition. In all Leucaena lines there was a significant increase in nodule DM pot-1 between the Ca0 and Ca4 treatments. However, there was a decrease in nodule DM of lines 5 and 27A from the Ca3 to Ca4 treatment. Nodule DM of M. lathyroides and L. bainesii was only affected to a limited extent over the range of treatments Ca0 to Ca3, but at Ca4 a significant reduction occurred in both species. In all species CaCO3 additions progressively increased the concentration of Ca in the plant tops. The positive DM responses were considered to be primarily due to Ca, although Al may have had a confounding effect, especially in L. leucocephala. Line 3 of L. leucocephala had the highest Ca concentration as well as the greatest reduction in Al concentration.