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  • Crop production variability...
    Anderson, Weston; Seager, Richard; Baethgen, Walter; Cane, Mark

    Agricultural and forest meteorology, 05/2017, Letnik: 239
    Journal Article

    •ENSO poses a risk to agriculture that is correlated across hemispheres.•ENSO life-cycles force production anomalies that follow a multi-year evolution.•ENSO accounts for ∼72, 30 and 57% of maize, soy and wheat production variability.•ENSO-induced yield anomalies are not static in time, and have changed in Brazil.•Increases in the frequency of crop harvesting have increased ENSO-induced anomalies. In this analysis we show how globally coherent teleconnections from life-cycles of the El Niño Southern Oscillation (ENSO) lead to correlated crop production anomalies in North and South America. We estimate the magnitude of ENSO-induced Pan-American production anomalies and discuss how increasing crop harvesting frequency may affect Pan-American production variability. We find that ENSO accounts for ∼72%, 30% and 57% of Pan-American maize, soybean and wheat production variability, respectively. ENSO-induced production anomalies are greatest for maize, with median anomalies of ∼5% of Pan-American production. ENSO-induced yield anomalies for maize and soybeans tend to be of the same sign in North America and southeast South America but of an opposite sign in northeast Brazil. Teleconnections for wheat are more complicated because ENSO affects wheat yields via lagged soil moisture teleconnections in the US and an increased probability of disease in South America, but anomalies tend to be of the same sign in North America and southeast South America. After broadly characterizing ENSO-induced production anomalies, we demonstrate that they are not static in time. Increasing crop harvesting frequency has affected the correlated risks posed by ENSO. We use a soil water balance to show that in Brazil changing to a safrinha cropping cycle increases both the mean water stress and the ENSO-induced soil water content anomalies during flowering in both the maize and soybean seasons, which is a result of increasing evaporative demand during times of lower precipitation and moving the flowering seasons into months with strong ENSO teleconnections. Increasing crop harvesting frequency in Brazil has therefore increased ENSO-induced production variability of soybeans and maize.