Effect of fertiliser and water supply on the growth, nutrient status and photochemical efficiency of Eucalyptus pilularis seedlings in a phosphorus-deficient soil

Abstract

SummaryA factorial pot trial, using a clay loam P-deficient soil, was conducted with two fertiliser rates (a) unfertilised and (b) fertilised with N, P, K and Mg, and with water supply within the range of 20% to 95% field-capacity (FC). Within the growth period of 180 days, plants of Eucalyptus pilularis Smith were exposed to increasing drought. Growth and photochemical efficiency were measured under these conditions and leaves and stems were analysed for biomass and nutrients.As judged by photochemical efficiency, fertilised plants were more stressed than unfertilised plants, where exposed to severe drought. As pre-conditioned plants displayed greater tolerance to drought than non-conditioned plants, it is recommended that where seedlings are to be planted in drought-prone areas, fertiliser application should be reduced and drought periods imposed during the nursery stage.Both stem and leaf nutrient concentrations increased with fertiliser application. On the other hand, leaf nutrient concentration decreased with increasing water supply, but stem concentration did not. It follows that the stem nutrient concentration may be the better indicator of the nutrient status of E. pilularis seedlings and this should be subject to further investigation.