Abstract
To produce sufficient food with limited arable lands has been a challenging issue. Thus, identification of
the main factors influencing crop productivity has attracted the attention of many researchers. Fengqiu
County of Henan Province, located in North China was chosen as study area; soil property and
agronomic practice data of 111 sites were collected during the 2009 growing season. Measurement on
soil parameters were made on top-soil (0 to 20 cm) and sub-surface soil (20 to 40 cm) of sampling sites,
while agronomic practices data were obtained through survey using questioner. The relative importance
of soil parameters and agronomic practices in influencing yield variability was analyzed with step-wise
linear regression analysis and classification and regression tree (CART) model. The results showed that
the level of soil nutrient content in the study area was relatively low. Soil electrical conductivity (EC)
was the most important parameter in determining wheat yield variability. Agronomic practices had great
impact on wheat yield. Among the variables of agronomic practices, nitrogen fertilizer rates was the
most crucial for wheat production. In order to increase local wheat yields in region scale, some
management practices, such as scientific irrigation, manure application for improving soil fertility,
should be implemented. The recommended quantity of nitrogen fertilizer ranged between 1.34 and 2.60
q/ha with higher wheat yields.
Key words: Wheat yield, soil properties, agronomic practices, nitrogen fertilizer, classification and regression
tree (CART).
