Risk Assessment And Low Carbon Strategies Of Winter Wheat And Summer Maize Production In North China Plain Under Climate Change

Long-term response strategies of crop production to climate change included not only adaptation strategies of reducing the impacts of climate change on crop production, but also mitigation strategies of reducing greenhouse gas emissions to slow climate change rate and amplitude. This study used statistical data, survey data, and field experiment data to make clear the spatiotemporal changes of heat, rainfall, and phenology of winter wheat and summer maize season under climate change in the North China Plain, estimate the risk of winter wheat and summer maize production in the future, analysis the carbon footprint of crop production in the North Chin Plain, and estimate the low-carbon technologies of winter wheat and summer maize, in order to put forward adaptation and mitigation strategies for winter wheat and summer maize production under the background of climate change. Main conclusions are listed as follows:(1) Significant climate resources change have occurred across the North China Plain in the past few decades, corresponding to global climate change. Base on historical meteorological data and phenology data, this study analyzed temporal and spatial variation of climate resources. The results showed that the GDD in various growth period of winter wheat were increased; the HDD in vegetative growth stage of winter wheat was increased, the HDD in reproductive stage and whole growth period of winter wheat were increased in southwest and northeast part, while the HDD were decreased in middle part of the North China Plain; the rainfall in various growth period of winter wheat were increased. The GDD in vegetative growth stage of summer maize was increased in south part, while decreased in north part of the North China Plain; The GDD in reproductive stage and whole growth period of summer maize were decreased in south part, while were increased in north part of the North China Plain; the rainfall in various growth period of summer maize were decreased in northeast part, while were increased in southwest of the North China Plain.(2) Climate warming accelerate crop growth, while cultivars shift delay crop growth. Base on historical meteorological data, phenology data, and field experiment data, this study assessed impacts of climate change and cultivars shift on phenology. The results showed that sowing date of winter wheat was delay in north part, while was advanced in south part in the North China Plain; green stage, heading stage and maturity of winter wheat were set in advance in the North China Plain. The length of vegetative growth stage, vegetative and reproductive stage, and the whole growth period length of winter wheat were shorten, but length of reproductive stage was prolong in the North China Plain. The flowering stage of summer maize was advanced, while mature stage was delayed in the North China Plain; the length of vegetative growth stage of winter wheat was shorten, but length of reproductive stage and whole growth period length were prolonged in the North China Plain. In addition, rainfall and average temperature were related to the length of the growth stage, and cultivars shift may prolonged crop growing duration.(3) The risk of winter wheat and summer maize production in the north part of North China plain were higher under background of climate change. Based on maximum entropy principle, this study assessed the risk of winter wheat and summer maize production in the North China Plain. The results showed that the heat risk of winter wheat production of north central part was higher than south part, the risk of reduced of rainfall in winter wheat season was higher in north part of the North China Plain; the risk of summer maize production of north part was higher than south part in the North China Plain, the spatial difference of risk of reduced of rainfall in summer maize season was not obvious.(4) Lowering crop production carbon emissions by improving production pattern. This study applied life cycle assessment carbon footprint method, carbon footprint of crop production in the North China Plain and the impact of different N fertilizer rate, irrigation rate, and tillage treatment on grain yield, greenhouse gas, and carbon footprint of winter wheat and summer maize. The results showed that the main components of carbon footprint were electricity for irrigation (30.25%), N fertilizer (23.07%), and direct emissions of N2O (19.83%). In addition, the results showed that reducing N fertilizer rate by25%for winter wheat lowered the greenhouse gas by49%compared with that under farmers’practice, with the yield was not significantly. Reducing irrigation rate by33%for winter wheat lowered the greenhouse gas by17.3%compared with that under farmers’practice, with the yield was not significantly. The treatments of N180kg ha-1, irrigation of150mm, and conventional tillage for winter wheat, the treatment of N225kg ha-1for summer maize was the best management practices that produced a lower carbon footprint with a favorable grain yield.(5) High yield and low carbon strategies of winter wheat and summer maize production in North China Plain under Climate Change. Base on the survey data, this study analyzed the carbon footprint of winter wheat and summer corn. Results showed that the main components of carbon footprint were electricity for irrigation, nitrogen fertilizer, and direct nitrous oxide emissions. Therefore, reducing electricity for irrigation, decreasing nitrogen fertilizer application rates, and lowering direct nitrous oxide emissions are the priority measures that will result in low-carbon agriculture, which were the strategies of high yield and low carbon for winter wheat and summer maize production in the North China Plain.