Contrasting impacts of two types of El Nino on the yields of early rice in Southern China
Sun, R.; Li, J.; Feng, J.; Hou, Z.; Zhang, Y.
Agronomy Journal 112(2): 1084-1100
ISSN/ISBN: 0002-1962 DOI: 10.1002/agj2.20014
Rice (Oryza sativa L.) production in southern China (SC) is important to Chinese food security and sensitive to climate change. This study investigates the contrasting effects of eastern Pacific (EP) El Nino and central Pacific (CP) El Nino on early rice yields in SC during boreal early summer (May-June-July, or MJJ) for the first time. During EP El Nino events, early rice yields usually exhibit a moderate increase across the entire SC region, whereas during CP El Nino events the yields decrease in about two-thirds of the region. The increase and decrease of yields correspond to .86 and 1.54% of the mean total yield during the study period, respectively. The effects of EP and CP El Nino events on early rice yields are significantly different over nearly half of the harvested areas in SC. Their difference mainly derives from the variability in rainfall associated with the two types. During MJJ, EP events are accompanied by reduced rainfall across SC, which increases early rice yields. In contrast, CP events are accompanied by increased rainfall in northeastern SC, resulting in unfavorable growing conditions. Although temperature affects early rice yields in SC, it is not the major contributor to the yield differences. Our findings highlight the importance of investigating the impacts of both types of El Nino on crop yields separately; and provide a possible climatological mechanism, linking the different locations of sea surface temperature anomalies (SSTAs) with SC early rice yields differences, through atmospheric teleconnection effects on local climatic factors.