| As the important driving force of social development,energy plays a huge role in promoting the rapid development of modern economic society.The energy was consumed hugely with the rapid economic and social development,and caused a series of problems,such as fossil energy crisis,environmental pollution,and further aroused people's thinking on the energy development strategy,so that's given a boost to the renewable energy,and the energy plants were the most development in the raw material of renewable energy,and the non-food energy plants were massively cultivated on the marginal land for the massive raw material of renewable energy might be the most applicable under ensuring the national food security.The Jerusalem artichoke was the good candidate for these.In addition to it's energy properties and high stress resistance,Jerusalem artichoke was also widely used in food,forage,medicine,ecological remediation and other fields,however as the lack of elite variety and high yield cultivation measures seriously limited the development of Jerusalem artichoke industry.So this research was based on the previous study on sowing,plant density,water and fertilization regulation and other cultivation measures,and through analysed the variation of growth and photosynthetic characteristics of 15 varieties with different yield performance and the effect of plastic film mulching on the Jerusalem artichoke yield,and comprehensively discussed the physiological and ecological mechanism of high yield formation of Jerusalem artichoke and the mechanism of the plastic film mulching influence on the Jerusalem artichoke yield,and provided the theoretical basis and technical support for the optimization of high yield cultivation measures of Jerusalem artichoke in semi-arid rain-fed agricultural areas.The results as follows:1.The high yield cultivars exhibited significant improved in leaf area index,plant height and stem diameter,the shoot biomass was reached 8.28 t ha-1 and was2.43 times that of the low yield cultivars.The photosynthetic capacity was also improved in the high yield cultivars,and the dark respiration rate,light compensation point and light saturation point was only 49.19%,43.28%and 81.2%compared with the low yield cultivars and reduced the photosynthetic consumption and improved the utilization of week light.The sexual reproduction capacity was reduced of high yield cultivars,and the natural seed set of high yield cultivars was only 3.74%,while the low yield cultivars was 16.19%.The traits associated strongly with high yield included a high plant height,stem diameter,leaf area index;a low dark respiration rate,light compensation point,and light saturation point;and a long vegetative growth period.In Jerusalem artichoke tuber yield component,compared with average weight per tuber,the increasing of tuber number per plant was more beneficial to increase of tuber yield of high yield cultivars,and the inulin content and total sugar content were also an increasing trend.2.The plastic film mulching could significantly improved the top soil temperature in the early growing season,and the full plastic film mulching was better than the half plastic film mulching,the highest monthly average increase 6.75?,and seedlings appeared 1-2 weeks in advance,however,there was no effect on the germination rate and mature stage,it's also significantly enhanced the plant height,stem diameter,leaf area index compared with no plastic film mulching and the highest increase of 17.65%,39.07%,52.88%and improved the tuber number per plant and tuber yield of Jerusalem artichoke especially in the full plastic film mulching and the dry year was better than the wet year,such as the highest tuber yield of full plastic film mulching was 48.66 t ha-1,and the highest tuber yield of half plastic film mulching was 38.1 t ha-1 of dry year in 2016,while the highest tuber yield of full plastic film mulching was 44.15 t ha-1,and the highest tuber yield of half plastic film mulching was 35.64 t ha-1 of wet year in 2018.Although the full plastic film mulching could effectively improved the tuber yield,the high yield was obtained at the expense of the large consumption of soil water,and yet could alleviate the overconsumption of soil water in the wet year.3.The full plastic film mulching was significantly improved tuber yield,and the growth of Jerusalem artichoke at various stage was better than the no plastic film mulching from seedlings.The warming effect was mainly appeared in the first two month and then disappeared almost in the Jerusalem artichoke cultivation,while the warming effect was throughout the growing season in no cultivation,in general the plastic film mulching improved the surface soil temperature.The average soil temperature of growing season was 16.22?in full plastic film mulching with Jerusalem artichoke cultivation,while the average soil temperature of growing season was only 14.14?in no plastic film mulching with Jerusalem artichoke cultivation,and the average soil temperature of growing season was 18.93?in full plastic film mulching with no Jerusalem artichoke cultivation,while the average soil temperature of growing season was 15.34?in no plastic film mulching with no Jerusalem artichoke cultivation,and the relative variation trend of soil temperature was almost consistent with the atmospheric temperature in no Jerusalem artichoke cultivation.The rainfall was effectively captured and maintained in the soil,and there was even a deeper leakage under full plastic film mulching,while the soil moisture balance was almost achieved in the first three months without mulching,and the soil water content increased due to the heavy rainfall in August,and the soil water storage of 200 cm soil profiles in the whole growing season increased 66.9 mm.However the variation was closely related to grow in the Jerusalem artichoke cultivation,and the soil water storage of 200 cm soil profiles in the whole growing season almost achieved the balance in the no plastic film mulching as more rains during the growing season,but it's decreased 56.7 mm in the full plastic film mulching.This was fully reflected the huge need of soil water in the Jerusalem artichoke high yield.On the whole,this study illuminated the physiological and ecological mechanism of high yield formation of Jerusalem artichoke,and the importance of plastic film mulching,espically the full plastic film mulching in high yield cultivation in semi-arid rain-fed agricultural areas,furthermore revealed the mechanism of full plastic film mulching improved Jerusalem artichoke yield from the change of soil hydrothermal status.These results provided some theoretical and technical support to the high yield cultivation and breeding of Jerusalem artichoke in semi-arid area. |
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