| With increasing population and shrinking agricultural land,greater agricultural production is needed in the future.Agricultural production is important for society development and shows high sensitivity to climate change.Crop yield shows differential responses to climate change in diverse regions of the world.Climate change can increase the spatial and temporal variability of agricultural production,and thus affect food security.Global mean air temperature will increase 1-3.7 oC in the end of this century,and the rising rate of minimum temperature at nighttime is higher than maximum temperature at daytime.With global warming,precipitation patterns will change in the future.North China Plain is one of major agricultural production regions in China,while the responses of crop growth to climate change in this region remains unclear.Assessing the responses of crop yield in this region to nighttime warming and increased precipitation are important to accurately predict the changes of crop growth under climate change scenarios in the future.The manipulative experiment including four treatments(control,passive nighttime warming,increased 30% precipitation,and passive nighttime warming plus increased 30% precipitation)was conducted in North China Plain.This experiment explores the responses of crop production to climate change by assessing the effects of nighttime warming and increased precipitation on photosynthetic and respiration rate,sugar and starch consumption,biomass,as well as yield.The analysis of precipitation distribution found that the precipitation during middle growing period accounted for 64.66% and 45.42% in 2016 and 2017,respectively.However,the precipitation proportion during late growing period was 57.94% in 2018.Nighttime warming increased nighttime soil temperature by 0.61 oC,and increased precipitation enhanced soil moisture by 2.30 V/V%.Nighttime warming increased soil pH by 0.05(absolute change),but had no effects on inorganic-N concentration,soil total carbon(STC),or total nitrogen(STN).No effects of increased precipitation on soil pH,inorganic-N concentration,STC,or STN were found.Increased precipitation improved soil pH by 0.10 in 2018,but had no effects in 2016 and 2017.Neither nighttime warming nor increased precipitation affected leaf respiration rate,the consumption of sugar and starch at nighttime,or leaf photosynthesis of peanut.Nighttime warming had no effect on peanut biomass,but increased precipitation improved it by 5.65%.Total biomass of peanut linearly increased with soil pH and soil moisture,respectively.Stepwise multiple regression analyses showed that soil pH,soil moisture and tiller number together accounted for 58% of variations in total biomass.Across the three years,nighttime warming decreased pod number by 6.65%,but had no effects on single pod weight or pod yield.Increased precipitation improved tiller number,pod number,and pod yield by 4.93%,8.44%,and 7.08%,respectively.However,increased precipitation decreased pod weight by 5.09%.Pod number was negatively dependent on nighttime soil temperature,but positively dependent on soil moisture and tiller number.Pod weight was positively correlated with total biomass and harvest index.Stepwise multiple regression analyses found that harvest index,total biomass and soil moisture together accounted for 67% of variations in pod weight.Nighttime warming and increased precipitation had different effects on peanut in North China Plain.Nighttime warming reduced grain number,but did not affect pod yield.The enhancement of pod number rather than the decrease of pod weight under increased precipitation,leading to stimulations of grain yield.These observations showed the positive effects of increased precipitation on peanut in North China Plain and improved the mechanism understandings of the response of crop growth and yield to climate change.These findings can provide basic data and theoretical support for policy developments under climate change scenarios in the future. |
