Influence of Climate Change and Mechanized Harvesting on the Maize (Zea mays L.) Planting and Northern Limits in Northeast China

Background Northeast China is one of the most important maize producing area in China. Due to temperature limitations on crop growth, whether this area can realize mechanical kernel harvesting maize (MKHM) variety will directly affect the stable development of maize in the region. The northern limits of early-maturing MKHM variety was analyzed under climate change in the study. Results The mean temperature during maize growth period increased at a rate of 0.22 °C/10a from 1960 to 2018. The average growth period for early-, middle- and late-maturing common harvest maize (CHM) variety was 123, 135 and 140 days, respectively, and the accumulated temperature above 10 °C (AAT10) was 2400 °C, 2800 °C, and 3100 °C. The early-maturing MKHM variety growth period was about 20 days longer than that of early-maturing CHM variety, and thus the AAT10 of MKHM variety was 2700 °C. During 2000-2018, the northern limits for the early-maturing CHM variety planting were located from south of Nenjiang and Wudalianchi (47°98' N-49°74' N), while the northern limits for the early-maturing MKHM variety was located in south Keshan, Nehe and Hailun (46°32' N-48°70' N), which was about 148 km southward compared to the northern limits of early-maturing CHM variety. Conclusion This study not only confirmed the northern limits of early-maturing MKHM variety, but also indicated that the development of MKHM variety offsets the influences of climate change on the northern limits of maize planting, which is very important for provide the sustainable development of maize in the region. This article is protected by copyright. All rights reserved.