Abstract:

To improve the soil fertility and reduce the pests and diseases by green manuring, a study on different soil layer water storage at different wheat growth stages, red spider occurrence quantity, basal stalk rot incidence and the correlation was conducted in wheat field under green manuring in summer fallow period by large area contrast method at different altitudes in 2018. The results showed that the different layer soil water storage at high altitude was higher than that at low altitude in different green manure stubble before winter and at jointing stage, and the red spider occurrence was opposite; the red spider occurrence was significantly different in different green manure stubble at same altitude (P<0.01), and the later the green manuring time, the larger the red spider occurrence quantity with same crop green manure stubble. The linear relationship between the 0-100, 100-200 and 0-200 cm soil layer water storage and the red spider occurrence was a significantly negative correlation (P<0.05) at wheat jointing stage at low altitude, but no difference at high altitude; before wheat overwintering, the linear relationship between the water storage of 100-200 cm soil layer and the red spider occurrence was a significantly negative correlation (P<0.05) at high altitude, and that of the water storage of 0-100 and 0-200 cm soil layer and the red spider occurrence was the same at low altitude. The basal stalk rot incidence of green manure stubble at low altitude and high altitude was 0.56%-1.59% and 0.00%-0.00% respectively, among them, there was a significantly negative correlation between 0-100 cm soil layer water storage before winter, 0-100, 100-200 and 0-200 cm soil layer water storage at jointing stage and basal stalk rot incidence (P<0.05) at low altitude; the mean correlation coefficient between different soil layer water storage and basal stalk rot incidence was larger at jointing stage than that before overwintering at low altitude. This study can provide a theoretical basis for the application of green manure to reduce pests and diseases, and to select suitable green manure stubble for different areas.

Key words: green manuring, rotation stubble, water storage in wheat field, red spider, basal stalk rot incidence