Climate Suitability And Cost-benefit Analysis Of Northward Winter Wheat Under Climate Change Background In Ningxia

Climate change offers a favorable condition for northward winter wheat, the planting area of winter wheat has expanded year by year in Ningxia, so it has a great significance on cropping systems and crop distribution. However, the evaluation of climate suitability and economic feasibility of winter wheat of Ningxia is still very little. In this paper, based on meteorological data, scenario data, crop model, field and household surveys, we will analyze the characteristics of climate change and costs and benefits of winter wheat in Yellow River Irrigation Region of Ningxia in 1961-2009, compare the characteristics of climate change and costs and benefits of winter wheat in 2011-2030 with baseline, and by setting the discount rate, calculate and analyze the NPV of winter wheat in future to reveal the principle of northward winter wheat in Ningxia and propose adaptation strategies and measures, then provide the basis for promoting northward winter wheat and enhance the adaptation results to climate change. The main conclusions are as follows:1. After planting winter wheat in the north, the≥0℃accumulated temperature before wintering period, the≥0℃accumulated temperature in growth period, the mean and minimum temperatures in January of winter, the mean temperature of mid-March wheat was gradually increased, it's useful for fostering strong vaccine, offering a meteorological indemnification for passing winter safely, avoiding frost of winter wheat and reducing the chance of late spring coldness; The mean temperature of jointing stage-heading Stage was increased, it's not benefit for prolonging the process of differentiation of spike, the maximum temperatures of filling stage were increasd year by year which will lead to the early maturity of winter wheat, especially the days that the maximum temperature of filling stage is higher than 32℃were increased, which lead to the possibility of dry hot wind. But winter wheat mature earlier than spring wheat, the risk of meeting dry hot wind is lower.2. The production, costs and benefits of winter wheat were higher than spring wheat; the production, costs and benefits of interplanting of winter wheat and maize were higher than interplanting of spring wheat and maize; the production, costs and benefits of multiple cropping of winter wheat vegetable were higher than interplanting of winter wheat and maize or interplanting of spring wheat and maize; the production, costs and benefits of rice were higher than winter wheat, but were lower than interplanting of winter wheat and maize or multiple cropping of winter wheat vegetable, therefore, interplanting of winter wheat and maize or multiple cropping of winter wheat vegetable have big advantage than other cropping pattern.3. Under A2 and B2 scenrios, the mean temperature of every growth period is mainly increased, but the fluctuation of temperature is very big, and there are many years that the temperature is lower than baseline. The≥0℃accumulated temperature before wintering period, the≥0℃accumulated temperature in growth period, the mean and minimum temperatures in January, the mean temperature of mid-March, the mean temperature of heading and flowering stages will increase than baseline, the absolute value of negative accumulated temperature, the days that the extreme minimum temperature was lower than -18℃, days that the temperature is lower than -2℃between mid-March and mid-April will decrease in the same time, all of these are useful for winter wheat, but the days that the maximum temperature of filling stage is higher than 32℃will increased, the maximum temperature turn higher, the minimum temperature turn lower, which will pose a threat to the stability of production of winter wheat.4. In addition to the yield of winter wheat would increase under A2 scenario, the other cases would decrease. The yield of spring wheat would dereased more than winter wheat, and the yield of winter wheat and spring wheat would decrease more under the B2 scenario.5. The icrement of NPV of wheat wheat– spring wheat is the biggest in the future, the second one is the NPV of interplanting of winter wheat and maize-rice, the NPV of interplanting of winter wheat and maize - interplanting of spring wheat and maize is as high as multiple cropping of winter wheat vegetable - interplanting of spring wheat and maize, so it's better to interplanting of winter wheat and maize than rice or spring wheat.6. It is emphased that improving the quality is as one of the most important targets im adjusting the breeding targets of the winter wheat. The adjustments of the irrigation systems, cropping systems are all the relavant adaptative options in Ningxia, in the same time, strengthen guidance and support for winter wheat from government, in order to protect food security and increase the income of farmers.