Nitrogen and phosphorus nutrition and stoichiometry in the response of maize to various N rates under different rotation systems

Better understanding of plant nutrition and nutrient interactions is of critical importance for developing best management practices in crop production. A three-year study was conducted to examine N and P nutrition and their association in maize as affected by rotation system, N application rate and hybrid maize. Rotation by N treatments were composed of maize–alfalfa (MA), maize–soybean (MS) and continuous maize (MM), fertilized in maize year at 0, 50, 100 and 150 kg N ha⁻¹, respectively. The two maize varieties were glyphosate-resistant (RR) non-Bt (non-Bt) and stacked RR + Bt near-isoline (Bt) hybrids. Our data showed that grain yield, stover, and total aboveground (or shoot) dry matter, N and P uptake (except for stover P) in amounts followed the order MA > MS > MM and were well responsive to N rates. Grain and shoot N and P contents of Bt maize was greater (P