不同耕作措施旱地小麦生产应对气候变化的效应分析

为探索气候变化对小麦产量影响的机制和规律,在田间试验的基础上通过调试APSIM模型参数,并对模型进行检验,然后用APSIM模型模拟温度和CO₂浓度两因素七水平小麦产量,分析了3种耕作措施下小麦产量对温度和CO₂浓度的响应及敏感性强度。结果表明,不同耕作措施条件下,小麦产量随CO₂浓度升高呈二次抛物线上升型变化,但会出现报酬递减,且免耕覆盖的增产效应大于传统耕作和免耕2种耕作措施;小麦产量随温度升高呈二次抛物线型变化,其中传统耕作和免耕呈二次抛物线递减型变化,并呈叠加递减效应,而免耕覆盖呈二次抛物线拐点型变化,拐点值为0.94℃时,小麦产量可达到2 818.3 kg/hm²。温度和CO₂浓度互作对小麦产量的敏感性分不敏感、正敏感和负敏感区域,且免耕覆盖的敏感性变化较小。在3种耕作措施中,免耕覆盖CO₂浓度升高小麦的增产效应可以补偿高温所导致的减产,并且温度和CO₂浓度具有更好的协同促进作用。免耕覆盖小麦生产具有较好应对温度和CO₂浓度变化的能力,可以缓减气候变化带来的负效应。

The effects of climate change on dryland wheat production under different tillage systems

In order to explore the influence mechanism and regulation of climate change on wheat yields, the parameters of APSIM model were firstly modified and then verified according to the data collected from field experiment. APSIM model was used to survey the effect and sensitivity of elevated CO₂ concentration and temperature on wheat yield under 3 tillage systems. The results show the relationships between wheat yield and the CO₂ concentration were quadratic parabola that shows an increased change and the yield will coincide with the diminishing return when CO₂ concentration increase. Meanwhile, the increasing effect of wheat yield of no tillage with stubble mulching (NTS) is greater than that of conventional tillage (T) and no tillage (NT). The relationships between wheat yield and temperature were quadratic parabola. Wheat yield and temperature of T and NT show a decreased change of quadratic parabola, and the contribution of temperature to the yield will coincide with the superimposed decreasing effect. Wheat yield and temperature under NTS show inflection point type change of quadratic parabola, temperature threshold is 0.94℃. Sensitivity of wheat yield to interaction of temperature and CO₂ concentration is divided to insensitivity, positive sensitivity and negative sensitivity. Sensitivity under NTS treatment changes little. In 3 tillage systems, the increasing effect of wheat yield caused by elevated CO₂ concentration can compensate for the yield reduction due to high temperature under NTS treatment, and there exists better interaction effect between CO₂ concentration and temperature. Preferably NTS can deal with the change of temperature and CO₂ concentration better, and it can reduce the negative effect of climate change.