title: Maize yield gaps caused by non-controllable, agronomic, and socioeconomic factors in a changing climate of Northeast China.
abstract: Closing the gap between current and potential yields is one means of increasing agricultural production to feed the globally increasing population. Therefore, investigation of the geographic patterns, trends and causes of crop yield gaps is essential to identifying where yields might be increased and quantifying the contributions of yield-limiting factors that may provide us potentials to enhance crop productivity. In this study, the changes in potential yields, attainable yields, potential farmers' yields, and actual farmers' yields during the past five decades in Northeast China (NEC) were investigated. Additionally the yield gaps caused by non-controllable, agronomic, and socioeconomic factors were determined. Over the period 1961 to 2010 the estimated regional area-weighted mean maize potential yield, attainable yield, and potential farmers' yield were approximately 12.3 t ha(-1), 11.5 t ha(-1), and 6.4 t ha(-1) which showed a decreasing tendency. The actual farmers' yield over NEC was 4.5 t ha(-1), and showed a tendency to increase (p<0.01) by 1.27 t ha(-1) per decade. The regional mean total yield gap (YGt), weighted by the area in each county dedicated to maize crop, was 64% of potential yield. Moreover, 8, 40, and 16% reductions in potential yields were due to non-controllable factors (YGI), agronomic factors (YGII), and socioeconomic factors (YGIII), respectively. Therefore, the exploitable yield gap, considered here as the difference between the potential yield and what one can expect considering non-controllable factors (i.e. YGt-YGI), of maize in NEC was about 56%. The regional area-weighted averages of YGt, and YGIII were found to have significant decreases of 11.0, and 10.7% per decade. At the time horizon 2010, the exploitable yield gaps were estimated to equal 36% of potential yield. This led to the conclusion that the yield gap could be deeply reduced by improving local agronomic management and controlling socioeconomic factors.
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Rd., Haidian District, Beijing 100193, China.
authors.forename: Zhijuan
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Rd., Haidian District, Beijing 100193, China. Electronic address: yangxg@cau.edu.cn.
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Agronomy, Kansas State University, 2108 Throckmorton Hall, Plant Sciences Center, Manhattan, KS 66506, USA.
authors.forename: Xiaomao
authors.initials: X
authors.lastname: Lin
authors.affiliation: School of Natural Resources, University of Nebraska-Lincoln, 3310 Holdrege Street, Lincoln, NE 68583, USA.
authors.forename: Kenneth G
authors.initials: KG
authors.lastname: Hubbard
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Rd., Haidian District, Beijing 100193, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Lv
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan West Rd., Haidian District, Beijing 100193, China; Ningxia Institute of Meteorological Sciences, Yinchuan 750002, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
keywords: Climate zone; Maize; Northeast China; Up-scaling; Yield constraints; Yield gaps