Journal of Geographical Sciences ›› 2012, Vol. 22 ›› Issue (1): 29-45 .doi: 10.1007/s11442-012-0909-2

• Climate and Environmental Change • Previous Articles     Next Articles

Spatio-temporal responses of cropland phenophases to climate change in Northeast China

LI Zhengguo1,2, TANG Huajun1,2, YANG Peng1,2, WU Wenbin1,2, CHEN Zhongxin1,2, ZHOU Qingbo1,2, ZHANG Li1,2, ZOU Jinqiu1,2   

  1. 1. Key Laboratory of Resources Remote Sensing &|Digital Agriculture, Ministry of Agriculture, Beijing 100081, China;
    2. Institute of Agricultural Resources &|Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China
  • Received:2011-06-06 Revised:2011-06-27 Online:2012-02-15 Published:2011-12-26
  • Supported by:

    National Basic Program of China (973 Program), No.2010CB951502; National Natural Science Foundation of China, No. 40930101, No. 41001381 and No. 41001246; Ministry of Finance of China through Non-profit National Research Institute, No. IARRP-2011-015

Abstract:

We investigated the responses of cropland phenophases to changes of agricultural thermal conditions in Northeast China using the SPOT-VGT Normalized Difference Vegetation Index (NDVI) ten-day-composed time-series data, observed crop phenophases and the climate data collected from 1990 to 2010. First, the phenological parameters, such as the dates of onset-of-growth, peak-of-growth and end-of-growth as well as the length of the growing season, were extracted from the smoothed NVDI time-series dataset and showed an obvious correlation with the observed crop phenophases, including the stages of seedling, heading, maturity and the length of the growth period. Secondly, the spatio-temporal trends of the major thermal conditions (the first date of ≥10℃, the first frost date, the length of the temperature-allowing growth period and the accumulated temperature (AT) of ≥10℃) in Northeast China were illustrated and analyzed over the past 20 years. Thirdly, we focused on the responses of cropland phenophases to the thermal conditions changes. The results showed that the onset-of-growth date had an obvious positive correlation with the first date of ≥10℃ (P < 0.01), especially in the northern part of the Songnen Plain, the eastern part of the Sanjiang Plain and the middle and eastern parts of Jilin Province. For the extracted length of growing season and the observed growth period, notable correlations were found in almost same regions (P < 0.05). However, there was no obvious correlation between the end-of-growth date and the first frost date in the study area. Opposite correlations were observed between the length of the growing season and the AT of ≥10℃. In the northern part of the Songnen Plain, the eastern part of the Sanjiang Plain and the middle part of Jilin and Liaoning Provinces, the positive correlation coefficients were higher than the critical value of 0.05, whereas the negative correlation coefficients reached a level of 0.55 (P < 0.05) in the middle and southern parts of Heilongjiang Province and some parts of the Sanjiang Plain. This finding indicated that the crop growth periods were shortened because of the elevated temperature; in contrast, the extended growth period usually meant a crop transformation from early- or middle-maturing varieties into middle or late ones.

Key words: cropland phenophase, SPOT/VGT, NDVI time series, climate change, Northeast China