ASSESSMENT OF EXTRACTANTS FOR AVAILABLE FE AND SOIL FACTORS AFFECTING IRON CHLOROSIS IN UPLAND RICE IN SOUTHWESTERN NIGERIA.

Authors

  • O. A. OSlNAME
  • V. A. BANJOKO
  • R. A. SOBULO

Keywords:

Fe, Fe uptake, DTPA extractant, 1N NH4OAc, organic carbon, pot trials

Abstract

Available Fe in 23 surface soils from southwestern Nigeria was determined with five ectractants, namely: 1N NH4OAc, 0.01 M EDTA, pH 7.0; (2)1N NH4OAc, pH 4.8 (3) 0.01M EDTA; (4) 1N NaOAc, pH 4.8 and (5) 0.005M DTPA and correlated with Fe uptake by rice plants (CV, ART8) grown under upland conditions in pot trials in the glasshouse. 0.005 M DTPA showed the highest correlation (r = 0.54**) and 1N NH4OAc pH 4.8 showed the least correlation (r = 0.35), with plant Fe uptake. The range of available Fe extracted by 0.005 M DTPA and 1N NH4OAc + 0.01 EDTA was 1.8 6.7 ppm and 3.3 10.5 ppm respectively.

Regression analysis indicated that soil pH is a strong factor controlling both Fe availability and Fe uptake by upland rice in the moderately acid tropical soils. Organic carbon accounted for 17.4% and 15.0% of available Fe extracted in 1N NH4OAc + 0.01 M EDTA, pH 7.0 and 0.005 M DTPA respectively. 0.005 M DTPA extractant appeared the best of the five extractants for assessing the availability of Fe in the moderately acid tropical soils. Incorporation of organic manures - poultry and brewers grain wastes. improved Fe uptake by the upland rice plants in a pot trial.

Published

2020-10-05