Abstract:Straw mulching is one of the core techniques of conservation tillage, which can reduce soil erosion and improve soil water use efficiency. Some researchers believe that straw mulching is conducive to wheat growth, while some researchers repute that straw mulching could hinder winter wheat growth. In order to investigate the effect of maize straw mulching on winter wheat growth in North China region under double cropping area, a three-year (2014 to 2016) field experiment was carried out in Zhuozhou City, Hebei Province conservation tillage experiment land. The experiment was performed using randomized complete block design with three replications. A series of straw mulching were arranged in field experiment, including 5t/hm2（OM）, 4t/hm2（EM）, 3t/hm2（SM）, 2t/hm2（FM）, 1t/hm2（TM）and 0t/hm2 (NM), which was controlled trials. The effect of maize straw mulching on soil volume water content, wheat emergence rate, wheat leaf area index, maize root dry weight and yield were evaluated. The results indicated that there was a linear relationship between maize straw mulching quantity and soil water content, the soil water content was increased with the increase of straw mulching amount. The emergence rate of wheat was increased with the increase of straw mulching amount, and FM treatment got the maximum emergence rate. The wheat emergence under FM treatment was significantly higher than those under TM, NM, SM, EM and OM treatments, and the average emergence rate under FM treatment was increased by 6.9%, 10.0%, 11.9%, 23.8% and 33.7%, respectively, compared with those under TM, NM, SM, EM and OM treatments during the period from 2014 to 2016. The mean wheat LAI under FM, TM, NM, SM, EM and OM treatments was 5.3, 4.5, 3.6, 4.0, 3.3 and 3.0, respectively, in the whole wheat growing season during the period from 2014 to 2016. The maximum mean wheat root density of wheat under FM, TM, NM, SM, EM and OM treatments was 0.98cm/cm3, 0.95cm/cm3, 0.93cm/cm3, 0.93cm/cm3, 0.86cm/cm3 and 0.67cm/cm3, respectively, during the period from 2014 to 2016. The mean yield of winter wheat under FM treatment was increased by 2.94%, 7.56%, 7.91%, 11.50% and 13.53%, respectively, compared with TM, NM, SM, EM and OM treatments during the period from 2014 to 2016. Finally, it was concluded that appropriate amount of straw mulching (2t/hm2) could promote wheat growth and increase yield. The seeding rate should be increased and the qualities of notillage seeders should be improved, especially in anti-blocking device and sowing depth consistency. The research result can be helpful to the promotion of the technology of straw return in annual maize-wheat rotation cropping region of North China.
