Climatic Causes of Maize Production Loss under Global Warming in Northeast China

Yanling Song,Hans W Linderholm,Guangsheng Zhou,Yi Luo,Jinxia Xu

doi:10.3390/su12187829

Abstract

Maize (Zea mays L.) is one of the most important staple crops in Northeast China, and yield losses are mainly induced by climate anomalies, plant diseases and pests. To understand how maize yield loss is affected by global warming, daily precipitation and temperatures, together with provincial agricultural data sets, were analyzed. The results showed that the accumulated temperature, an important factor in agricultural productivity, increased by 5% in 1991–2017, compared to 1961–1990, and that the frequency of low temperatures decreased by 14.8% over the same time period. An increase in drought by 21.6% was observed from 1961–1990 to 1991–2017, caused by decreased growing-season precipitation by −4 mm/decade. In addition, days with heavy rain in August and September increased slightly in Northeast China. In general, maize growth responded positively to the increased thermal conditions; in 1961–1990, 22.7% of observed maize yield-loss cases were due to low temperatures, but only 10% in 1991–2017. However, during the same time, the number of drought-induced yield loss cases increased from 27.3% to 46.7%. Moreover, yield loss cases caused by heavy rainstorms increased from 4.5% to 13.3%, indicating that heavy rainstorms have become an increasing threat to agriculture in Northeast China over the last three decades. In total, at least 70% of cases of provincial yield losses in Northeast China over the last three decades could be attributed to climatic factors. The frequency of climate hazards has changed under global warming, resulting in new challenges for agriculture. While drought and low temperatures were the primary causes for climate-induced yield losses before the 1990s, negative impacts from extreme events, mainly drought but also heavy precipitation, have increased in the last three decades, associated with global change. Farmers, agricultural scientists, and government policy makers could use these results when planning for adaptation to climate change.

Highlights

Climate change has already had an observable impact on the global food production [1]
A serious drought in 2000, lasting from May to July in most parts of Northeast China (NC), had a profound impact on the maize production, which was reduced by 0.5 million tons in the Liaoning province, where the crop failed to mature at about 1 million hectares [10]
TT◦Chwe·day,se12a38r24w◦5Ci°t·Chdtlhdowe, 1ce3or2ltdh°eCasntdtghrlaootwwineinrtghthesaepnarsetohvnaiottuiensmttphheererpeartyueevraeiorasu.fstetrhr1e9e91yewarass. 2003, when the accumulated temperature (AT) was Determining a drought index threshold is important when characterizing the impact of drought on maize production

Summary

Introduction

Climate change has already had an observable impact on the global food production [1]. Unusually low temperatures during the summer of 1969 resulted in accumulated growing season temperatures that were 200–300 ◦C·d below normal This resulted in crops being unable to mature before the first frost, reducing the maize production by 6.55 × 103 million kg over the entire region—e.g., decreasing the yield in Heilongjiang by 32% [10]. Another example relates to drought, which is one of the major climatological hazards that frequently influences crop growth in China.

Study Area and Data

Low Temperature

Droughts and Rainstorms

Yield Loss Rate

Results

Climatic Reasons for Maize Production Loss