Optimizing nitrogen use efficiency in maize with novel microencapsulated inhibitors: A 15N isotope tracer study
摘要
Urease inhibitors (UI) and nitrification inhibitors (NI) enhance nitrogen fertilizer utilization efficiency (NUE). Microencapsulated materials using melamine–formaldehyde resin as wall material can slow the degradation rate of inhibitors and improve their efficacy. However, the ultimate fate of fertilizer N under microencapsulated inhibitor treatment remains to be quantified.
MethodsThis study systematically quantified the fate distribution of fertilizer N, between gas emissions, soil material uptake, and crop absorption, after application to soil under microencapsulated inhibitor treatment using 15N isotope tracing technology.
ResultsResults indicate that microencapsulation technology, via the melamine-formaldehyde resin wall material that retards inhibitor degradation in soil, extended the detectable shelf life of N-(n-butyl)thiophosphorotriamide (NBPT) and 3,4-dimethylpyrazole phosphate (DMPP) from 35 days to 63-72 days. At the seedling stage, fertilizer-derived soil ammonium N (NH₄⁺-N) was 23.6% higher in the micro-encapsulated NBPT (MN) treatment than in the conventional NBPT treatment. At the jointing stage, microencapsulation treatments elevated NH₄⁺-N levels by 13.3%-16.7% over conventional treatments. Furthermore, the delayed-release properties boosted maize grain N uptake by 24.1%-30.4% and improved NUE by 4.9%-6.2%. Regarding soil residual N, MN retained 15.6% of applied N in the soil, while the micro-encapsulated DMPP (MD) treatment reduced residual fertilizer N by 16.3% compared to DMPP.
ConclusionsMicroencapsulation technology effectively addresses the limitation of short efficacy periods in traditional inhibitors by delaying the degradation process, thereby increasing corn yields while reducing N loss.