Effect of nitrogen, phosphorus and potassium application on grain yield and qualities of high-oil and high-starch corn

Effects of nitrogen, phosphorus and potassium application on grain yield and qualities of high-oil corn Nongda 115 and high-starch corn Baiyu 109 were studied. The results showed that corn grain yields of combined application of N 195 (kg/hm~2), P_2O_5 60 (kg/hm~2), and K_2O 105 (kg/hm~2) (NPK) were significantly higher compared to PK, NK, and NP treatments, respectively. Yield of applied N, P, and K increased by 15.9%, 6.9%, and 12.1% for high-oil corn, respectively, by 20.3%, 8.6%, and 12.7% for high-starch corn, respectively. Grain total protein content, and prolamine and albumin content increased by N application for high-oil corn and high-starch corn, and also increased by P and by K application for high-oil corn. While the effect of P or K application on high-starch corn grain protein and its components was not observed. Grain total amino acid content and essential amino acid content increased by N application by 0.83 and 0.41 percentage point for high-oil corn, and by 1.18 and 0.36 percentage point for high-starch corn, respectively, and increased by P or by K application for high-oil corn. While the effect of P and K application on high-starch corn grain amino acid and its components was not found. Insignificant increase of grain total starch and amylopection content by N, P, K application for high-oil corn and high- starch corn was observed. While obvious decrease of grain amylose content by N, P, K application was found, respectively. Grain fatty acid content, and sub-oleic acid and oleic acid content increased by N application by 0.83, 0.41 and 0.30 percentage point for high-oil corn, and by 0.34, 0.18, and 0.13 percentage point for high-starch corn, respectively. While the effect of P and K application on high-oil corn and high-starch corn grain fatty acid content and its components was not observed.