Response of Physiological Growth Characteristics of Rice to Different Biodegradable Mulching and Irrigation Methods in Cold Region of Northeast China

Highlights The tested biodegradable mulch film can be rapidly degraded in rice fields in cold regions and has good applicability. The degradation rate of white mulch film is faster than that of black film before the induction period, and the degradation law after the induction period is opposite. The combination of mulching film and water-saving irrigation can effectively enhance the photosynthetic capacity and dry matter transport of rice in cold regions. Through comprehensive evaluation, we found that the combination of ridge irrigation and mulching FC plastic film has the best effect on environmental protection and rice growth. Abstract. To reveal the mechanism of influence of different types of biodegradable plastic film mulching and irrigation combinations on the physiological growth characteristics of rice in cold regions, eight types of film mulching irrigation methods were designed, which combined four types of plastic film mulching and two types of irrigation methods for a total of nine treatments. The study analyzed the degradation law of degradable plastic film in rice fields in cold regions, and the effects of film-mulching irrigation methods on rice photosynthetic characteristics, dry matter transport, and rice yield. The results showed that the three biodegradable plastic films were suitable for the rice fields in the northeast cold region. Except for the jointing stage, mulching irrigation treatments could increase the chlorophyll content and net photosynthetic rate of rice, and the improvement degree showed a downward trend with the growth of rice. The film mulching irrigation treatments improved rice stems and leaves dry matter transport and grain contribution. The comprehensive evaluation based on the comprehensive index method showed that the combination of ridge irrigation and thin black biodegradable mulch is the best combination of biodegradable plastic film mulching and irrigation in the study area. Keywords: Biodegradable mulching, Comprehensive index method, Dry matter transportation, Irrigation method, Photosynthetic character.