Influence of integrated nutrient management on selected enzyme activities in relation to selected soil chemical properties in rice field at Badeggi Niger state, Nigeria.

Abstract

Soil enzyme activities provide an easy, relatively rapid and low cost production to monitor soil health. Integrated soil management effect on urease and acid phosphatase activities was determined by collecting soil samples from four (4) rice farmers field in Badeggi, Niger State. Where; Control, Farmers’ practice (NPK); 150 kg ha-1 NPK (15:15:15), OCP special blend; (NPK 15:15:15 fertilizer fortified with Zn and Ca.), 600 kg ha-1, cow dung; (5-ton ha- 1), ½ cow dung + ½ NPK and ½ cow dung + ½ OCP special blend fertilizer were applied accordingly. The experiment was laid out in a Randomized Complete Block Design (RCBD) replicated four times. Data were collected according to standard and subjected to Analysis of Variance using GenStat (11th Edition). Significant means were separated using Least Significant Difference (LSD) (p ≤ 0.05). Results showed that Cow dung application consistently resulted in the highest urease activity throughout the growth stages of rice production, indicating its significant role in promoting ammonium volatilization. This was evident with urease activities of 665 µg NH4+ N g-1 soil h-1, 511 µg NH4+ N g-1 soil h-1 and 427 µg NH4+ N g-1 soil h-1 at planting, flowering and at harvest respectively, surpassing all other treatments. Similarly, cow dung application and its combination with NPK and OCP showed notable effect on acid phosphatase activities all through the different growth stages. There was positive relationship between urease activity and pH while it negatively correlated with the other observed nutrients. Whereas, acid phosphatase activity had positive relationship with pH, Organic carbon, Total nitrogen and Available Phosphorus. The observed significant response variation among treatments at different growth stages of rice, highlights the dynamic nature of soil as it influenced the existing microbes (enzyme activity) in the rhizosphere in response to the various soil management practices adopted by farmers. Hence altering soil health and its productivity. Therefore, the use of OCP special blend for improvement of soil available phosphorus should be encouraged while the sole use of cow dung should be discouraged on rice field.