Insufficient and excessive N fertilizer input reduces maize root mass across soil types

Quantifying maize root response to nitrogen (N) fertilizer, soil texture, and weather is crucial understand complex soil-root-plant processes. We performed a 2-year x 4 locations (sand content range: 5–95%) N treatments (range: 0 336 kg ha?1) field experiment in Iowa, U.S. (1) determine the of traits (2) develop generalized functions aid understanding prediction mass shoot (R:S) ratio. Deep samples (0?210 cm, increments 30 cm) were collected using core approach at early middle grain fill period quantified mass, length, C concentrations. In addition, yield biomass was measured. Root had different responses fertilizer input. maximized 168 ha?1; zero excessive fertilization decreased by 33 17 %, respectively. Nitrogen significantly affected only top cm layer. Soil texture dry year (root positively associated with silt clay), but not wet year, suggesting that moisture overwhelms effect texture. The combined data (N rates years) revealed negative relationship between R:S ratio yield. This resulted new set equations (e.g., upper bound = e(–1.5 – 0.04*yield)) can replace constant used literature. Yield, which commonly measured, integrates effects environment, management, genetic variation; hence proposed be widely applied. study provides evidence plant are levels mineral nutrition. Results enhance biophysical models