Shaping wave-like maize canopy via interval DHEAP spraying to optimize light distribution and yield under high plant density

Poor light interception constrains maize (Zea mays L.) yield potential under high planting densities. This study evaluated an "interval spraying" strategy using N,N-diethyl-2-hexanoyl-oxygen radical ethylamine (2-ethyl chloride) phosphonic acid salt (DHEAP) to construct a wave-like canopy. Unlike traditional regulators (e.g., ethephon) DHEAP features a neutral pH and optimized stability, allowing for "inhibition compensation" regulation of internode elongation and plant height. In a two-year field experiment with maize hybrid Xianyu 335 at four densities (7.5, 9.0, 10.5, 12.0 × 10 4 plants ha -1 ), DHEAP was applied to alternating four-row strips at the V8 stage. Results showed DHEAP significantly reduced sprayed plant (Tr) height while unsprayed plants (T0) maintained height, establishing a stable wave-like architecture. This structure significantly ( p