Experiments on the reproductibility of results from EUF soil extracts with possible improvements resulting from these experiments

Summary The reproducibility of EUF-Ca, K, Na, P, B, NO₃–N and EUF extractable N for fraction 1 (200 V, 20° C, 30 minutes) was within a CV range of 4.54–12.28%.The summation of results for fraction 1 (200 V, 20°C, 30 minutes) and fraction 2 (400 V, 80°C, 5 minutes) gave an improved CV range of 4.23–8.81%.EUF-Mg obtained from fraction 1 (200 V, 20°C, 30 minutes), fraction 2 (400 V, 80°C, 5 minutes) and the acid fraction gave a CV of 6.81%.Results from the acid fraction gave poor reproducibility for Zn, (CV=45.1%). The CV of 12.5% for Mn is low compared to the CV of 30–40% usually obtained.The recovery of Zn, Mn and Mg from the acid fraction was improved. The reproducibility of Zn and Mg was also improved by (a) reducing the sources of contamination; (b) introducing a second filter at the cathode; (c) steeping the filters for 48 hours.