增温对西北半干旱区马铃薯产量和品质的影响

Influence of increased temperature on the potato yield and quality in a semiarid district of Northwest China

过去50年,西北半干旱区干旱化趋势明显加强,对作物生产产生了明显影响。未来50年全球气候继续变暖,直接影响农业生产,必将对粮食安全提出新的挑战。采用红外线辐射器田间增温模拟实验研究表明,随着温度升高马铃薯播种—出苗—现蕾—开花—成熟各生长阶段天数都发生变化。增温0.5—2.5℃,马铃薯播种—出苗、出苗—现蕾阶段分别缩短1—4 d、1—2d,现蕾—开花、开花—熟阶段分别延长1—2 d、1—10 d,马铃薯播种—成熟全生育期延长1—5 d。伴随温度升高,马铃薯全生长期有所延长,特别是盛花期至茎叶枯萎阶段延长明显,这将有利于防止茎叶早衰和淀粉的积累。增温显著减少了每株薯块量、提高了每块薯重,马铃薯产量总体呈现递增趋势,但差异不显著。增温1.5—2.5℃,马铃薯增产1.0%—3.5%。增温0.5—2.0℃,马铃薯干物质含量从22.4%增加到24.5%,淀粉含量从72.1%增加到74.4%,粗蛋白含量从1.82%减少到1.52%,还原糖含量从0.24%减少到0.22%,表明增温有利于马铃薯干物质和淀粉的积累,不利于粗蛋白和还原糖的形成。

Climate change is predicted to increase both drought frequency and duration. Arid and semiarid regions, which account for 45% of the global land area, support 38% of the global population, but are regions that have very fragile ecological and water resource systems. Over the past 100 years, the global mean temperature increase for arid regions was 0.94℃/100a, which is higher than the average global mean temperature increase of 0.74℃/100a. Over this period, global arid and semiarid regions have become drier and drier. About 10%-20% of the global arid and semiarid land has become seriously degraded, the area of extremely arid land has doubled and the total area of land classed as arid is nearly 30%. Large scale droughts have recently occurred in North America, Africa, Europe, South America and Australia, resulting in major changes to terrestrial ecosystems, the carbon balance and food security. The continuous aridification over 30 years of the semiarid region of North China has led to serious environmental degradation and a lack of water resources, which has seriously restricted sustainable regional development. The semiarid area in Northwest China is also sensitive to climate change. Over the past 50 years, the air temperature has risen and rainfall has fallen, which have caused the climate to become warmer and drier. A series of changes, including higher temperatures, increased drought and warmer winters, have significantly influenced crop production. Over the next 50 years, the global climate will continue to warm, which will directly affect agriculture and may have an impact on grain safety. The global annual potato yield is 320 million tons, next only to wheat, corn and rice, which makes potato the fourth largest crop in the world. The annual potato yield in China is 80 million tons. The climatic, biological and soil environment in the semiarid area of loess plateau in Northwest China is very suitable for potato growing and is the main potato production area in China. Potato can grow over a range of temperatures. Some studies have shown that a low temperatures increase the formation and accumulation of dry matter in potato stems and tubers. High temperatures, over the longer term, increase the number of small tubers, decrease the tuber specific weight, reduce the amount of dry matter transferred to the tuber and influence potato quality. This study investigated whether climate change will negatively influence the yield and quality of potatoes grown in semiarid areas of Northwest China. An experimental study based on simulated farm warming using infrared radiators showed that potato growth stage lengths, such as： sowing-seedling, emergence-bud and emergence-blooming-maturity, changed as the temperature increased. If the temperature increased by 0.5-2.5 ℃, then the sowing-seedling emergence and the seedling emergence-bud emergence growth stages were shortened by 1-4 d and 1-2 d, respectively, the bud emergence-blooming and the blooming-maturity growth stages were prolonged by 1-2 d and 1-10 d, respectively, and the whole growing period from sowing to maturity was prolonged by 1-5 d. The whole growing period, especially the fully blooming to stem and leaf senescence stage, was prolonged as the temperature increased and this was advantageous as it prevented the early senescence of stems and leaves and increased the accumulation of starch. Warming significantly decreased the number of potatoes produced by each plant, but increased the weight of each potato. Thus overall potato yield increased, but not significantly. If the temperature increased by 1.5-2.5 ℃, then potato yield improved by 1.0%-3.5%. The dry matter, starch and vitamin C contents increased as the temperature rose, but the protein and reducing sugar contents significantly decreased. The results suggested that warming may not have an effect on potato yield, but may have a significant influence on potato quality. When the temperature was increased by 1.5-2.5℃, the potato yield improved by 1.0%-3.5% and when the temperature was increased by 0.5-2.0℃, the potato dry matter content increased to 24.5% from 22.4%, the starch content was reduced to 1.52% from 1.82% and the reducing sugar content fell to 0.22% from 0.24%. This means that increasing temperatures improve potato dry matter accumulation and starch content but reduce the formation of crude protein and reducing sugar.