Research On Crops Pattern For Adapting To Climate Change

Hydrothermal resources are determined by global climate change,which causes farmland ecosystems to deviate from their inherent natural processes and form a compound crops pattern.Along with climate change,new opportunities and challenges are aroused for agricultural activities.Therefore,it’s necessary to conduct a research on the spatio-temporal pattern of crops and agroclimatic resources,and to propose some effective regulating strategies for agricultural production adapting climate change to avoid negative effects and to improve crop climatic suitability.Three main crops(Maize,Soybean and Rice)in northeastern China were selected to analyze by using crop distribution data,growth and development data and climate data and trend analysis method,spatial analysis method in this study.Based on maximum entropy model,the spatio-temporal characteristics of crops pattern and agroclimatic resource pattern were systematically analyzed.The influence of dominant climatic factors on crop suitability was quantified,and then the climate suitability of crops in study area was zoned.Finally,according to the distribution and growth status of the planting area,the corresponding strategies of climate adaptability were addressed.The main conclusions of this study are as follows:(1)Both the beginning date of frost-free period and potential growth period showed clearly tendency of ahead,while the ending date postponed and consequently the duration of growing season prolonged.The daily mean temperature and accumulated temperature of potential growth period increased,while daily mean solar radiation decreased.Total precipitation,daily mean evapotranspiration,total evapotranspiration and total solar radiation showed a fluctuatual tendency.The spatial distribution of agroclimatic resources were extremely uneven,more in the south and plain area,and less in the north and mountainous area.The spatial heterogeneity of agroclimatic resources changes are strong,and the variability increased from the south to the north.(2)The crop climatic suitability models based on Max Ent performed good.There areX4,3 and 5 dominant factors affecting the suitability of maize,soybean and rice,respectively.For maize,the accumulated temperature,daily mean temperature,total precipitation and total evapotranspiration are dominant factors.For soybean,total precipitation,daily mean temperature and daily mean evapotranspiration are dominant factors.And for rice,duration of potential growth period,the beginning date of potential growth period,total precipitation,total evapotranspiration and daily mean solar radiation are dominant factors.The climate suitable area and the most suitable area of ?the main crop showed obvious northeastward expansion,and the area of?unsuitable area decreased gradually.(3)From 1990 to 2013,the total area of ?crops in Northeast China was 39.4 ×104km2—41.7 × 104km2,accounting for 31.72%-33.53% of the total area of ??the study area,and showed a gradual expanding trend.The area of ??dryland increased firstly and then decreased,and the area of ??paddy field was expanded rapidly.The area ratio of dryland and paddy field decreased from 10: 1 to 6.27: 1.The number of dryland patches was increased,indicated an obviously fragmentation process.There were significant differences in the spatial position and the transfer direction between dryland,paddy field and non-agricultural land.The change of the central position of the two kinds of transfer modes(from dryland and non-agricultural land to paddy field)are close to 200 km,and both of the transfer modes are from southwest to northeast.Based on the above results,the crops pattern in 2013 was taken as an example for putting forward the strategy of adapting to climate change.Regulating strategy of planting area: to reduce the planting in unsuitable planting areas,and to expand acreage in the potential planting areas.Regulating strategy of planting time: the region which the beginning of actual growth period was much earlier than those of potential growth period should be sowing or transplanting earlier,and the proportion higher than the average could be the regulating intensity.Regulating strategy of planting varieties: region with low utilization of heat resources should be changed to planting varieties with longer growth period.Based on the analysis of the spatio-temporal characteristics of farmland vegetation and agroclimatic resources,the quantitative relationship between cropclimate suitability and climatic factors was explored,which not only can deepen the understanding of the inherent law of adaptation to climate change for farmland vegetation,but also can provides an important practical guidance for agricultural production activities to avoid the disadvantages and improve crop climate adaptability in Northeast China.