Using a single base addition for lime requirement of Acrisols: a case study in Southeastern Vietnam

ABSTRACT Developing lime requirement (LR) methods for routine use is one of the key tasks for agronomists because such methods would provide accurate lime recommendations while saving time, labour, and cost. This paper examined the effects of testing conditions to LR and tested if a single base addition can be routinely used for LR estimates. With Acrisols from Southeastern Vietnam (0–30 cm), results showed that lime rates, equilibrium times, and shaking had great effects on LR. A lime rate [as saturated Ca(OH)2] of 0.10 × 10−3 kg CaCO3 kg soil−1 in 1:1 soil:0.01 M CaCl2, a 90-min equilibrium, and continuous shaking are the optimum conditions for LR estimates. Titration with a single base addition using the optimum conditions estimated 85.8% of LR by the reference method. The estimation rate can be as high as 97% if more prediction errors were ignored in low LR soils. Although prediction errors are likely, titration with a single base addition can be suitable for routine use on Acrisols in Southeastern Vietnam, with further testing, adjustment, and validation.