Rainfall characteristics of growth duration of early and late rice in South China

Objective  Rainfall characteristics during each growth period of early and late rice in South China region were studied to provide a decision-making basis and have an active meaning for double cropping rice production and disaster prevention and reduction in South China.

Method  Using daily precipitation data of 47 meteorology observational stations from 1960 to 2008 in South China, regional average cumulative precipitation and daily average percentage of rainstorm in each growth period of early and late rice were calculated, and annual average value and spatial distribution characteristic of rainfall were analyzed.

Result  There was almost the same accumulated rainfall with above 600 mm in early rice (673.5 mm) and late rice (611.5 mm)periods. The maximum accumulated rainfall occurred in seedling stage of late rice (256.6 mm), and the minimum value occurred in heading stage of late rice (26.9 mm). The maximum daily average precipitation in growth periods of early and late rice occurred in filling stage (8.2 mm) and seedling stage (8.3 mm) respectively, and the minimum value occurred in seedling stage (4.1 mm) and filling stage respectively. The daily average rainstorm and precipitation gradually increased with the growth stage for early rice, but decreased for late rice. The results of spatial distribution showed that the accumulated rainfall and frequency of heavy rainfall were closely related with the precipitation system in South China during the flood season. Early rice was mainly affected by the monsoon system, and late rice was mainly affected by the typhoon system. The high values of precipitation and rainstorm were mainly located in coastal areas.

Conclusion  Rainfall characteristics in the growth periods of early and late rice are different. The most important stage for preventing flood is filling stage for early rice, but tillering stage for late rice.