Effects of humus on growth and nutrient uptake of maize under saline and calcareous soil conditions

Abstract

Greenhouse research was conducted to determine the effects of soil application of humus, on dry matter and N, P, K, Ca, Mg, Fe, Cu, Zn, Mn and Na uptake of maize grown under calcareous and saline soil conditions. Stress conditions were obtained by adding 40% CaCO3 and 60 mM NaCl to the soil. Humus was applied to the soils at 0, 1 and 2 g kg(-1) doses at the beginning of the treatment. Solid humus and CaCO3 were mixed according to the application doses, and the total weight of the soil was adjusted to 5 kg. The mixture was homogenised and put into polyethylene-covered plastic pots (20 x 18 cm). A 60 mM NaCl solution was added to the salt-treated pots.

CaCO3 and NaCl both negatively affected the plants' growth, lowering the dry weights of the plants due to the stress, and decreasing the mineral nutrient amounts, except for sodium. Although the application of humus had no apparent affects on the control pots, which received no lime or salt applications, the humus applications had significant effects under the calcareous and saline conditions. The lower application dose of humus elevated the dry matter yield and some nutrient element uptakes under the stress conditions. The increases at the higher dose were found to be smaller than those at the lower dose of humus except for potassium and calcium uptake.

Soil application of humus could minimise the negative effects of saline and calcareous soil conditions on nutrient uptake and plant development but further studies are required to determine economical application levels.