Soil nitrogen transformation rates in 0–20 cm layer under soil film mulching

The experiment was conducted at the Shouyang Dryland Farming Experimental Station, Shanxi Province, China, based on a three-year field trial. Two modified cellulose materials—carboxymethyl cellulose ammonium (CMC-NH₄, with nitrogen supply and adsorption functions) and carboxymethyl cellulose sodium (CMC-Na, with adsorption function only)—were applied via spraying (S, forming a continuous film with warming effect) and row application (R, without film formation and no warming effect), with water spray as the control (CK).

Measured parameters include net nitrogen mineralization rate, net nitrification rate, net ammonification rate, denitrification potential, and nitrogenase activity (acetylene reduction assay, ARA). This dataset can be used to assess the effects of soil film mulching on soil nitrogen cycling and to disentangle the independent and interactive effects of warming, adsorption, and nitrogen supply functions.