Remediation effect of the combination of ditching drainage and agronomic managements on gleyed paddy field in Poyang Lake Region, China

【Objective】 Gleyed paddy field has the characteristics of frequently waterlogging, low soil temperature, poor soil structure, bad ventilated and high content of total reducing substances, which limit the advance of rice yield. Ditching drainage is regarded as an effective method in improving gleyed paddy field. Ridge culture, wet irrigation and winter plough could also regulate soil water condition, improve soil structure and reduce soil total reducing substances, then to improve gleyed paddy field. The combined effects of ditching drainage and agronomic managements on improving gleyed paddy field were studied. 【Methods】 A field experiment was conducted on a double rice gleyed paddy field to study soil total reducing substances, soil physical and chemical properties in Poyang Lake Region from 2012 to 2013. The main treatment included ditching drainage(D-D) and the auxiliary treatment with continuously flooded(CF), ridge culture(RC), wet irrigation(WI) and winter plough(WP). The rice yield and total soil reducing substances, and the rice straw and seed nutrient content after harvest in typical rice growing season were measured from 2012 to 2013. The remediation potential of ditching drainage and rice cultivation managements on gleyed paddy field were estimated. 【Results】 Ditching drainage, ridge culture(RC), wet irrigation(WI) and winter plough(WP) all could increase rice yield in gleyed paddy field. Compared to non-ditching drainage, the rice yield of continuously flooded, ridge culture, wet irrigation and winter plough under ditching drainage condition was increased by 12.8%, 10.1%, 13.3% and 13.3%, respectively. The combination practice of ditching drainage and water control management could increase rice yield obviously. The rice yield of the combination of ditching drainage and ridge culture was the highest in all the treatments, which reached 1.11-1.89 t/hm2. The ditching drainage had noticeable effects on reducing the soil total reducing substances, and the combination practice of ditching drainage and water control management could reduce soil total reducing substances significantly, the soil total reducing substances of the combination of D-D and RC were the lowest in all treatments, which reduced the soil total reducing substances by 1.11-1.87 cmol/kg. The soil total reducing substances increased with the increase of soil depth. Compared to non-ditching drainage, the ditching drainage increased the content of humus carbon and fulvic acid carbon of RC, WI and WP with no significant effect on the content of soil HM acid carbon. The ditching drainage could increase the soil cation exchange capacity and the content of soil organic carbon and available P considerably, with no significant effect on the pH, the content of available K and total N. The nutrient content and nutrient supplication condition of RC were much better than other water control management practices in this study. 【Conclusions】 The ditching drainage had steadily effects on increasing rice yield, reducing soil total reducing substances and improving soil physical and chemical properties in gleyed paddy field in Poyang Lake Region. The combination of ditching drainage and agronomic practices could improve the benefit of ditching drainage, and ridge culture shows the best combination effects among the treated practices. Therefore, the combination of ditching drainage and ridge culture is recommended in gleyed paddy field in Poyang Lake Region.