Some extractable iron contents as influenced by some organic manures application in the soils of Lake Geriyo, Adamawa state, Nigeria
Saddiq Abdullahi Muhammad1*, Solomon Rejoice Ibrahim1, Singh Lillan1 and Musa Aishatu Mala1
Organic manures are safer sources of plant nutrients and a good source of micronutrients therefore; pot experiments were carried out to estimate some extractable iron contents as influenced by organic manure application in the soils of Lake Geriyo, Adamawa state, Nigeria. Two types of organic manures; poultry droppings, cow dung and control were used for the experiment. Three levels of organic manures; 5, 10 and15 tons per hectare (ton ha-1)and three sampling time (30, 60 and 90 DAS were laid down in a completely randomized (CRD) design replicated three times. Results obtained revealed that rate, type of organic manures and time of submergence significantly (P ≤ 0.05) changed Fe content in the soil. Mean extractable iron concentrations of 42.01, 56.13 and 24.63 mgkg-1 were recorded for ammonium oxalate extractable iron, Citrate Bicarbonate Dithionite extractable iron and sodium pyrophosphate extractable iron in the first experiment while 45.81, 59.29 and 28.89 mgkg-1 were recorded for the second experiment respectively. However, CBD which extracts both amorphous and crystalline Fe recorded the highest Fe contents throughout the treatments with poultry droppings applied pots recording superior values than that of cowdung manure. similarly, higher values of oxa-Fe and Pyro-Fe were recorded in both manures compared to the control. In conclusion poultry droppings may result in iron accumulation and toxicity hence should be used with caution in the soil of Lake Geriyo and similar soils to avoid serious soil reduction leading to iron toxicity and soil phosphorus antagonism.
Keywords: Ammonium Oxalate, Citrate Bicarbonate Dithionite, Lake Geriyo, Sodium Pyrophosphate Extractable iron