Dr.Tarafdar,as I understand the enzyme activity  depends on continuous availability of requisite amount of substrate and optimal growth conditions. Many times substrate availability and moisture   may be limitations. Sometimes temperature extremes  may also influence the enzyme activity.

Looking at the extreme sensitivity of soil enzymes to any management practices  and other agro-pedological conditions , maintaining enzymatic activity within a time frame , though , looks apparently difficult , but with a desired substrate   , this could be made possible, otherwise , how do we get the  elevated response of added substrates , unless soil enzymes are activated over a period of time to translate  that condition into an overall plant response,  evaluated at whole plant level...

Hi J.C, what is the enzyme that you want to maintain?

It is phosphatases, Phytase and Aryl-sulphatases