Effects of precipitation and nitrogen on spring corn yield in black soil regions

The objective of this study was to distinguish effects of main growing factors on the corn yield under dry-farming conditions. A corn field experiment with three factors and four levels for each factor was conducted using the same corn cultivar and the same design in three consecutive years on a black soil classified as typic udolls of which the available nitrogen is middle but both available phosphorus and potassium are high. The results showed that, the most limiting factors to corn yield were respectively precipitation in growing season (PGS), rate of nitrogen fertilizer and available nitrogen contents of soil. Only when the PGS was greater than 280 mm, was nitrogen fertilizer effect statistically noticeable. The appropriate combination of nitrogen, phosphorus and potassium fertilizers increased the water use efficiency by 24.3% compared to no fertilizer treatment. Corn yield was positively correlated with the available nitrogen contents of soil too, meaning that higher soil available nitrogen contents are favorable to the increase in corn yield.