Impacts Of Climate Change On Potato Production In The Northwest Semi-arid Region

Potato,with the characteristics of strong adaptability, short growth period, rich nutritions, strong disaster relief capability,one of the main food crops in semi-arid regions of northwest China. For its high yield and big yield potential, potato becomes the fourth largest staple crops after rice, wheat and corn. Promote the potato industry vigorously is an important strategy to ensure food security in China.Global climate warming is causing adverse effects on potato production in semi-arid regions of northwest China, potato production of main producing areas showed a downward trend overall in recent decades. It is of great importance to study the impact mechanism and influence degreeof climate change on potato growth, the impact of future climate conditions on the growth and yield of potato and how to adjust productioncropping system to cope with the adverse effects of climate change for potato production in semiarid areas of northwest China.This study was based on the daily meteorological data of 40 meteorological stations from 1961 to 2010 and the 0.5°×0.5°rid data from 1961 to 2060 simulated by RegCM4 under RCP4.5 scenario given by National Climate Center, in combination with the WOFOST model,quantitative analyzed the effect direction and degree of future climate change on agricultural climate resources, temperature suitability, water suitability and light suitability of potato, planting regionalization of potato, potato growth period and yield of study areas.Also analyzed and demonstrated the feasibility of the measure to adjust sowing date in response to climate warming by combination of potato sowing experiments in Dingxi city and WOFOST simulation results, analyzed the temporal and spatial variation characteristics of the best seeding time under the background of future climate change in study areas, in order toprovide a reliable reference and basis for potato production in this area. In this paper, the main conclusions are as follows:1.From 1961-2010, climate in the study areas tended to be warming-drying in general, under the RCP4.5 scenario, this trend will continue, the climate still showed a warming-drying trend. Against this background, heat resources among the main reproductive period of potato (April-September),including average temperature, the≥10℃ accumulated temperature, the average temperature of the hottest month, the number of days of the daily maximum temperature>30℃ all showed a trend of increase. The first date when stably passing 10℃,which can reflect potato optimum sowing date was advanced. As for water resources,including precipitation and amount of moisture loss among the main reproductive period of potato both showed a trend of fluctuated falling.Potato prefers cool climate, a series of heat and water resources change due to "warming and drying"climate had a negative effect on potato growth and yield formation.2.Temperature suitability, water suitability and light suitability of potato among the main reproductive period all showed a trend of decrease in the study areas.Chose the environmental factor (altitude, slope, vegetation coverage) which plays the leading role for the growth of potato and key climate factors(precipitation of June-July,;≥10℃ accumulated temperature of April to September, average temperature in July, dryness index of April to September), and determine the weight of each factor by the method of analytic hierarchy process(AHP),consequently obtained potato planting zoning map of lkm resolution by calculation.Anaiysis obtained that suitable planting region of potato are mainly distributed in the midwest of the study areas,The region from middle of Wuwei, middle of Ningxia to west of yulin is the north boundary,while from Longnan in Gansu province to the northern of Guanzhong, Shaanxi is the south boundary. most suitable areas decreased and south boundary moved north with climate change in the future.3.The output simulated by WOFOST model showed that, potato production will present a downward trend in most of the study areas under the background of climate change in the future. In the next 50 years(2011～2060), potato production can be substantially increased in northwest region of the study area,including south of Wuwei, Lanzhou, Baiyin, and northwest of Ningxia by improving irrigation condition, compensate the negative impact of climate change on potato production to a certain extent.The impact of climate warming on potato growth period mainly displays in three aspects:optimum sowing date advanced, each development period advanced, the whole stages shorten.4. The experiment of potato sown on different sowing dates in Dingxi indicated that, the best seeding time of potatoin Dingxi should be the end of may or early June, about 30 days delay than traditional seeding time. The best sowing date of Dingxi in 2010 is June 9 through the simulation of WOFOST model,which is consistent with the experimental conclusion.On this basis,simulated the optimum sowing time of 40 stations in the whole study area during 1961-2060, and interpolated to grids of 1 km resolution.Resuits indicate that, the best sowing date of potato in the study areas shows the tendency of postpone, delay days between 0-40 days.This shows that,delaying sowing date was effective measures in response to the impact of climate warming on potatoes.The potato best seeding time of each site in the future obtained on the basin of regional climate model and WOFOST crop model, not only provides a new train of thought for the similar research,but also provides a reference and basis for the local potato production and planning.