The results showed that the wheat aphid population density was lower than the economic threshold for the whole growing period and the duration for efficiently preventing wheat aphids from damage was more than 7 months only by dressing seeds with 1.

To unveil the mechanism of effect of elevated CO_2 concentration and temperature increasing on growth,development and yield formation of rice,many physiological characteristics of rice were measured from the half-open CO_2-temprature gradient system,which treated whole growth duration of rice by different CO_2 concentrations and temperature levels.

Wheat with bunch plating covered over with plastic film in whole growing period is a new developed cultivation technique in recent years.

Characteristics of precipitation anomaly during whole growth period of spring wheat in the east of Yellow River in Gansu;